@> } while (cur_xref->num >=cite_flag) cur_xref=cur_xref->xlink; if (cur_xref==xmem && !an_output) { printf("%s","\n! Never used: <"); print_section_name(p); putchar('>'); mark_harmless(); @.Never used:

@> } section_check(p->rlink); } } @ @=@+static void section_check(name_pointer); @ @=section_check(root); @* Low-level output routines. The \TEX/ output is supposed to appear in lines at most |line_length| characters long, so we place it into an output buffer. During the output process, |out_line| will hold the current line number of the line about to be output. @d line_length 80 /* lines of \TEX/ output have at most this many characters; should be less than 256 */ @= static char out_buf[line_length+1]; /* assembled characters */ static char *out_buf_end = out_buf+line_length; /* end of |out_buf| */ static char *out_ptr; /* last character in |out_buf| */ static int out_line; /* number of next line to be output */ @ The |flush_buffer| routine empties the buffer up to a given breakpoint, and moves any remaining characters to the beginning of the next line. If the |per_cent| parameter is |true|, a |'%'| is appended to the line that is being output; in this case the breakpoint |b| should be strictly less than |out_buf_end|. If the |per_cent| parameter is |false|, trailing blanks are suppressed. The characters emptied from the buffer form a new line of output; if the |carryover| parameter is |true|, a |"%"| in that line will be carried over to the next line (so that \TEX/ will ignore the completion of commented-out text). @d c_line_write(c) fflush(active_file),fwrite(out_buf+1,sizeof(char),c,active_file) @d tex_printf(c) fprintf(active_file,"%s",c) @d tex_putc(c) fputc(c,active_file) @d tex_puts(c) fputs(c,active_file) @= static void flush_buffer(char *,boolean,boolean);@/ static void finish_line(void); @ @c static void flush_buffer( char *b, /* outputs from |out_buf+1| to |b|, where |b<=out_ptr| */ boolean per_cent,boolean carryover) { char *j=b; /* pointer into |out_buf| */ if (! per_cent) /* remove trailing blanks */ while (j>out_buf && *j==' ') j--; c_line_write(j-out_buf); if (per_cent) tex_putc('%'); tex_putc('\n'); out_line++; if (carryover) while (j>out_buf) if (*j--=='%' && (j==out_buf || *j!='\\')) { *b--='%'; break; } if (bout_buf) flush_buffer(out_ptr,false,false); else { for (k=buffer; k<=limit; k++) if (!(xisspace(*k))) return; flush_buffer(out_buf,false,false); } } @ In particular, the |finish_line| procedure is called near the very beginning of phase two. We initialize the output variables in a slightly tricky way so that the first line of the output file will be `\.{\\input cwebmac}'. @= out_ptr=out_buf+1; out_line=1; active_file=tex_file; tex_printf("\\input cwebma"); *out_ptr='c'; @ When we wish to append one character |c| to the output buffer, we write `|out(c)|'; this will cause the buffer to be emptied if it was already full. If we want to append more than one character at once, we say |out_str(s)|, where |s| is a string containing the characters. A line break will occur at a space or after a single-nonletter \TEX/ control sequence. @d out(c) {if (out_ptr>=out_buf_end) break_out(); *(++out_ptr)=c;} @= static void out_str(const char *);@/ static void break_out(void); @ @c static void out_str( /* output characters from |s| to end of string */ const char*s) { while (*s) out(*s++); } @ The |break_out| routine is called just before the output buffer is about to overflow. To make this routine a little faster, we initialize position 0 of the output buffer to `\.\\'; this character isn't really output. @= out_buf[0]='\\'; @ A long line is broken at a blank space or just before a backslash that isn't preceded by another backslash or a \TeX\ comment marker. In the latter case, a |'%'| is output at the break. @c static void break_out(void) /* finds a way to break the output line */ { char *k=out_ptr; /* pointer into |out_buf| */ while (true) { if (k==out_buf) @@; if (*k==' ') { flush_buffer(k,false,true); return; } if (*(k--)=='\\' && *k!='\\' && *k!='%') { /* we've decreased |k| */ flush_buffer(k,true,true); return; } } } @ We get to this section only in the unusual case that the entire output line consists of a string of backslashes followed by a string of nonblank non-backslashes. In such cases it is almost always safe to break the line by putting a |'%'| just before the last character. @= { printf("\n! Line had to be broken (output l. %d):\n",out_line); @.Line had to be broken@> term_write(out_buf+1, out_ptr-out_buf-1); new_line(); mark_harmless(); flush_buffer(out_ptr-1,true,true); return; } @ Here is a macro that outputs a section number in decimal notation. The number to be converted by |out_section| is known to be less than |def_flag|, so it cannot have more than five decimal digits. If the section is changed, we output `\.{\\*}' just after the number. @= static void out_section(sixteen_bits);@/ static void out_name(name_pointer,boolean); @ @c static void out_section( sixteen_bits n) { char s[6]; snprintf(s,6,"%d",(int)n); out_str(s); if (changed_section[n]) out_str("\\*"); @.\\*@> } @ The |out_name| procedure is used to output an identifier or index entry, enclosing it in braces. @c static void out_name( name_pointer p, boolean quote_xalpha) { char *k; /* pointer into |byte_mem| */ out('{'); for (k=p->byte_start; k<(p+1)->byte_start; k++) { if (isxalpha(*k) && quote_xalpha) out('\\'); @.\\\$@> @.\\\_@> out(*k); } out('}'); } @* Routines that copy \TEX/ material. During phase two, we use the subroutines |copy_limbo| and |copy_TeX| (and |copy_comment|) in place of the analogous |skip_limbo| and |skip_TeX| that were used in phase one. The |copy_limbo| routine, for example, takes \TEX/ material that is not part of any section and transcribes it almost verbatim to the output file. The use of `\.{@@}' signs is severely restricted in such material: `\.{@@@@}' pairs are replaced by singletons; `\.{@@l}' and `\.{@@q}' and `\.{@@s}' are interpreted. @= static void copy_limbo(void);@/ static eight_bits copy_TeX(void);@/ static int copy_comment(boolean,int); @ @c static void copy_limbo(void) { while (true) { if (loc>limit && (finish_line(), get_line()==false)) return; *(limit+1)='@@'; while (*loc!='@@') out(*(loc++)); if (loc++<=limit) { switch (ccode[(eight_bits)*loc++]) { case new_section: return; case translit_code: out_str("\\ATL"); break; @.\\ATL@> case '@@': out('@@'); break; case noop: skip_restricted(); break; case format_code: if (get_next()==identifier) get_next(); if (loc>=limit) get_line(); /* avoid blank lines in output */ break; /* the operands of \.{@@s} are ignored on this pass */ default: err_print("! Double @@ should be used in limbo"); @.Double @@ should be used...@> out('@@'); } } } } @ The |copy_TeX| routine processes the \TEX/ code at the beginning of a section; for example, the words you are now reading were copied in this way. It returns the next control code or `\.{\v}' found in the input. We don't copy spaces or tab marks into the beginning of a line. This makes the test for empty lines in |finish_line| work. @f copy_TeX TeX @c static eight_bits copy_TeX(void) { char c; /* current character being copied */ while (true) { if (loc>limit && (finish_line(), get_line()==false)) return new_section; *(limit+1)='@@'; while ((c=*(loc++))!='|' && c!='@@') { out(c); if (out_ptr==out_buf+1 && (xisspace(c))) out_ptr--; } if (c=='|') return '|'; if (loc<=limit) return ccode[(eight_bits)*(loc++)]; } } @ The |copy_comment| function issues a warning if more braces are opened than closed, and in the case of a more serious error it supplies enough braces to keep \TEX/ from complaining about unbalanced braces. Instead of copying the \TEX/ material into the output buffer, this function copies it into the token memory (in phase two only). The abbreviation |app_tok(t)| is used to append token |t| to the current token list, and it also makes sure that it is possible to append at least one further token without overflow. @d app_tok(c) {if (tok_ptr+2>tok_mem_end) overflow("token"); *(tok_ptr++)=c;} @c static int copy_comment( /* copies \TeX\ code in comments */ boolean is_long_comment, /* is this a traditional \CEE/ comment? */ int bal) /* brace balance */ { char c; /* current character being copied */ while (true) { if (loc>limit) { if (is_long_comment) { if (get_line()==false) { err_print("! Input ended in mid-comment"); @.Input ended in mid-comment@> loc=buffer+1; goto done; } } else { if (bal>1) err_print("! Missing } in comment"); @.Missing \} in comment@> goto done; } } c=*(loc++); if (c=='|') return bal; if (is_long_comment) @@; if (phase==2) { if (ishigh(c)) app_tok(quoted_char); app_tok(c); } @@; if (c=='{') bal++; else if (c=='}') { if(bal>1) bal--; else {err_print("! Extra } in comment"); @.Extra \} in comment@> if (phase==2) tok_ptr--; } } } done: @@; } @ @= if (c=='*' && *loc=='/') { loc++; if (bal>1) err_print("! Missing } in comment"); @.Missing \} in comment@> goto done; } @ @= if (c=='@@') { if (*(loc++)!='@@') { err_print("! Illegal use of @@ in comment"); @.Illegal use of @@...@> loc-=2; if (phase==2) *(tok_ptr-1)=' '; goto done; } } else { if (c=='\\' && *loc!='@@') { if (phase==2) app_tok(*(loc++))@t;@>@; else loc++; } } @ We output enough right braces to keep \TEX/ happy. @= if (phase==2) while (bal-- >0) app_tok('}'); return 0; @** Parsing. The most intricate part of \.{CWEAVE} is its mechanism for converting \CEE/-like code into \TEX/ code, and we might as well plunge into this aspect of the program now. A ``bottom up'' approach is used to parse the \CEE/-like material, since \.{CWEAVE} must deal with fragmentary constructions whose overall ``part of speech'' is not known. At the lowest level, the input is represented as a sequence of entities that we shall call {\it scraps}, where each scrap of information consists of two parts, its {\it category} and its {\it translation}. The category is essentially a syntactic class, and the translation is a token list that represents \TEX/ code. Rules of syntax and semantics tell us how to combine adjacent scraps into larger ones, and if we are lucky an entire \CEE/ text that starts out as hundreds of small scraps will join together into one gigantic scrap whose translation is the desired \TEX/ code. If we are unlucky, we will be left with several scraps that don't combine; their translations will simply be output, one by one. The combination rules are given as context-sensitive productions that are applied from left to right. Suppose that we are currently working on the sequence of scraps $s_1\,s_2\ldots s_n$. We try first to find the longest production that applies to an initial substring $s_1\,s_2\ldots\,$; but if no such productions exist, we try to find the longest production applicable to the next substring $s_2\,s_3\ldots\,$; and if that fails, we try to match $s_3\,s_4\ldots\,$, etc. A production applies if the category codes have a given pattern. For example, one of the productions (see rule~3) is $$\hbox{|exp| }\left\{\matrix{\hbox{|binop|}\cr\hbox{|ubinop|}}\right\} \hbox{ |exp| }\RA\hbox{ |exp|}$$ and it means that three consecutive scraps whose respective categories are |exp|, |binop| (or |ubinop|), and |exp| are converted to one scrap whose category is |exp|. The translations of the original scraps are simply concatenated. The case of $$\hbox{|exp| |comma| |exp| $\RA$ |exp|} \hskip4emE_1C\,\\{opt}9\,E_2$$ (rule 4) is only slightly more complicated: Here the resulting |exp| translation consists not only of the three original translations, but also of the tokens |opt| and 9 between the translations of the |comma| and the following |exp|. In the \TEX/ file, this will specify an optional line break after the comma, with penalty 90. At each opportunity the longest possible production is applied. For example, if the current sequence of scraps is |if_clause| |stmt| |else_like| |if_like|, rule 63 is applied; but if the sequence is |if_clause| |stmt| |else_like| followed by anything other than |if_like|, rule 64 takes effect; and if the sequence is |if_clause| |stmt| followed by anything other than |else_like|, rule 65 takes effect. Translation rules such as `$E_1C\,\\{opt}9\,E_2$' above use subscripts to distinguish between translations of scraps whose categories have the same initial letter; these subscripts are assigned from left to right. @ Here is a list of the category codes that scraps can have. (A few others, like |int_like|, have already been defined; the |cat_name| array contains a complete list.) @d exp 1 /* denotes an expression, including perhaps a single identifier */ @d unop 2 /* denotes a unary operator */ @d binop 3 /* denotes a binary operator */ @d ubinop 4 /* denotes an operator that can be unary or binary, depending on context */ @d cast 5 /* denotes a cast */ @d question 6 /* denotes a question mark and possibly the expressions flanking it */ @d lbrace 7 /* denotes a left brace */ @d rbrace 8 /* denotes a right brace */ @d decl_head 9 /* denotes an incomplete declaration */ @d comma 10 /* denotes a comma */ @d lpar 11 /* denotes a left parenthesis */ @d rpar 12 /* denotes a right parenthesis */ @d prelangle 13 /* denotes `$<$' before we know what it is */ @d prerangle 14 /* denotes `$>$' before we know what it is */ @d langle 15 /* denotes `$<$' when it's used as angle bracket in a template */ @d colcol 18 /* denotes `::' */ @d base 19 /* denotes a colon that introduces a base specifier */ @d decl 20 /* denotes a complete declaration */ @d struct_head 21 /* denotes the beginning of a structure specifier */ @d stmt 23 /* denotes a complete statement */ @d function 24 /* denotes a complete function */ @d fn_decl 25 /* denotes a function declarator */ @d semi 27 /* denotes a semicolon */ @d colon 28 /* denotes a colon */ @d tag 29 /* denotes a statement label */ @d if_head 30 /* denotes the beginning of a compound conditional */ @d else_head 31 /* denotes a prefix for a compound statement */ @d if_clause 32 /* pending \.{if} together with a condition */ @d lproc 35 /* begins a preprocessor command */ @d rproc 36 /* ends a preprocessor command */ @d insert 37 /* a scrap that gets combined with its neighbor */ @d section_scrap 38 /* section name */ @d dead 39 /* scrap that won't combine */ @d ftemplate 63 /* \\{make\_pair} */ @d new_exp 64 /* \&{new} and a following type identifier */ @d begin_arg 65 /* \.{@@[} */ @d end_arg 66 /* \.{@@]} */ @d lbrack 67 /* denotes a left bracket */ @d rbrack 68 /* denotes a right bracket */ @d attr_head 69 /* denotes beginning of attribute */ @= static char cat_name[256][12]; /* |12==strlen("struct_head")+1| */ @ @= {int c; for (c=0;c<256;c++) strcpy(cat_name[c],"UNKNOWN");} @.UNKNOWN@> strcpy(cat_name[exp],"exp"); strcpy(cat_name[unop],"unop"); strcpy(cat_name[binop],"binop"); strcpy(cat_name[ubinop],"ubinop"); strcpy(cat_name[cast],"cast"); strcpy(cat_name[question],"?"); strcpy(cat_name[lbrace],"{"@q}@>); strcpy(cat_name[rbrace],@q{@>"}"); strcpy(cat_name[decl_head],"decl_head"); strcpy(cat_name[comma],","); strcpy(cat_name[lpar],"("); strcpy(cat_name[rpar],")"); strcpy(cat_name[prelangle],"<"); strcpy(cat_name[prerangle],">"); strcpy(cat_name[langle],"\\<"); strcpy(cat_name[colcol],"::"); strcpy(cat_name[base],"\\:"); strcpy(cat_name[decl],"decl"); strcpy(cat_name[struct_head],"struct_head"); strcpy(cat_name[alfop],"alfop"); strcpy(cat_name[stmt],"stmt"); strcpy(cat_name[function],"function"); strcpy(cat_name[fn_decl],"fn_decl"); strcpy(cat_name[else_like],"else_like"); strcpy(cat_name[semi],";"); strcpy(cat_name[colon],":"); strcpy(cat_name[tag],"tag"); strcpy(cat_name[if_head],"if_head"); strcpy(cat_name[else_head],"else_head"); strcpy(cat_name[if_clause],"if()"); strcpy(cat_name[lproc],"#{"@q}@>); strcpy(cat_name[rproc],@q{@>"#}"); strcpy(cat_name[insert],"insert"); strcpy(cat_name[section_scrap],"section"); strcpy(cat_name[dead],"@@d"); strcpy(cat_name[public_like],"public"); strcpy(cat_name[operator_like],"operator"); strcpy(cat_name[new_like],"new"); strcpy(cat_name[catch_like],"catch"); strcpy(cat_name[for_like],"for"); strcpy(cat_name[do_like],"do"); strcpy(cat_name[if_like],"if"); strcpy(cat_name[delete_like],"delete"); strcpy(cat_name[raw_ubin],"ubinop?"); strcpy(cat_name[const_like],"const"); strcpy(cat_name[raw_int],"raw"); strcpy(cat_name[int_like],"int"); strcpy(cat_name[case_like],"case"); strcpy(cat_name[sizeof_like],"sizeof"); strcpy(cat_name[struct_like],"struct"); strcpy(cat_name[typedef_like],"typedef"); strcpy(cat_name[define_like],"define"); strcpy(cat_name[template_like],"template"); strcpy(cat_name[ftemplate],"ftemplate"); strcpy(cat_name[new_exp],"new_exp"); strcpy(cat_name[begin_arg],"@@["@q]@>); strcpy(cat_name[end_arg],@q[@>"@@]"); strcpy(cat_name[lbrack],"["); strcpy(cat_name[rbrack],"]"); strcpy(cat_name[attr_head],"attr_head"); strcpy(cat_name[attr],"attr"); strcpy(cat_name[alignas_like],"alignas"); strcpy(cat_name[using_like],"using"); strcpy(cat_name[default_like],"default"); strcpy(cat_name[0],"zero"); @ This code allows \.{CWEAVE} to display its parsing steps. @d print_cat(c) fputs(cat_name[c],stdout) /* symbolic printout of a category */ @ The token lists for translated \TEX/ output contain some special control symbols as well as ordinary characters. These control symbols are interpreted by \.{CWEAVE} before they are written to the output file. \yskip\hang |break_space| denotes an optional line break or an en space; \yskip\hang |force| denotes a line break; \yskip\hang |big_force| denotes a line break with additional vertical space; \yskip\hang |preproc_line| denotes that the line will be printed flush left; \yskip\hang |opt| denotes an optional line break (with the continuation line indented two ems with respect to the normal starting position)---this code is followed by an integer |n|, and the break will occur with penalty $10n$; \yskip\hang |backup| denotes a backspace of one em; \yskip\hang |cancel| obliterates any |break_space|, |opt|, |force|, or |big_force| tokens that immediately precede or follow it and also cancels any |backup| tokens that follow it; \yskip\hang |indent| causes future lines to be indented one more em; \yskip\hang |outdent| causes future lines to be indented one less em; \yskip\hang |dindent| causes future lines to be indented two more ems. \yskip\noindent All of these tokens are removed from the \TEX/ output that comes from \CEE/ text between \pb\ signs; |break_space| and |force| and |big_force| become single spaces in this mode. The translation of other \CEE/ texts results in \TEX/ control sequences \.{\\1}, \.{\\2}, \.{\\3}, \.{\\4}, \.{\\5}, \.{\\6}, \.{\\7}, \.{\\8} corresponding respectively to |indent|, |outdent|, |opt|, |backup|, |break_space|, |force|, |big_force| and |preproc_line|. However, a sequence of consecutive `\.\ ', |break_space|, |force|, and/or |big_force| tokens is first replaced by a single token (the maximum of the given ones). A |dindent| token becomes \.{\\1\\1}. It is equivalent to a pair of |indent| tokens. However, if |dindent| immediately precedes |big_force|, the two tokens are swapped, so that the indentation happens after the line break. The token |math_rel| will be translated into \.{\\MRL\{}, and it will get a matching \.\} later. Other control sequences in the \TEX/ output will be `\.{\\\\\{}$\,\ldots\,$\.\}' surrounding identifiers, `\.{\\\&\{}$\,\ldots\,$\.\}' surrounding reserved words, `\.{\\.\{}$\,\ldots\,$\.\}' surrounding strings, `\.{\\C\{}$\,\ldots\,$\.\}$\,$|force|' surrounding comments, and `\.{\\X$n$:}$\,\ldots\,$\.{\\X}' surrounding section names, where |n| is the section number. @d math_rel 0206 @d big_cancel 0210 /* like |cancel|, also overrides spaces */ @d cancel 0211 /* overrides |backup|, |break_space|, |force|, |big_force| */ @d indent 0212 /* one more tab (\.{\\1}) */ @d outdent 0213 /* one less tab (\.{\\2}) */ @d opt 0214 /* optional break in mid-statement (\.{\\3}) */ @d backup 0215 /* stick out one unit to the left (\.{\\4}) */ @d break_space 0216 /* optional break between statements (\.{\\5}) */ @d force 0217 /* forced break between statements (\.{\\6}) */ @d big_force 0220 /* forced break with additional space (\.{\\7}) */ @d preproc_line 0221 /* begin line without indentation (\.{\\8}) */ @^high-bit character handling@> @d quoted_char 0222 /* introduces a character token in the range |0200|--|0377| */ @d end_translation 0223 /* special sentinel token at end of list */ @d inserted 0224 /* sentinel to mark translations of inserts */ @d qualifier 0225 /* introduces an explicit namespace qualifier */ @d dindent 0226 /* two more tabs (\.{\\1\\1}) */ @ The raw input is converted into scraps according to the following table, which gives category codes followed by the translations. \def\stars {\.{**}}% The symbol `\stars' stands for `\.{\\\&\{{\rm identifier}\}}', i.e., the identifier itself treated as a reserved word. The right-hand column is the so-called |mathness|, which is explained further below. An identifier |c| of length 1 is translated as \.{\\\v c} instead of as \.{\\\\\{c\}}. An identifier \.{CAPS} in all caps is translated as \.{\\.\{CAPS\}} instead of as \.{\\\\\{CAPS\}}. An identifier that has become a reserved word via |typedef| is translated with \.{\\\&} replacing \.{\\\\} and |raw_int| replacing |exp|. A string of length greater than 20 is broken into pieces of size at most~20 with discretionary breaks in between. \yskip\halign{\quad#\hfil&\quad#\hfil&\quad\hfil#\hfil\cr \.{!=}&|binop|: \.{\\I}&yes\cr \.{<=}&|binop|: \.{\\Z}&yes\cr \.{>=}&|binop|: \.{\\G}&yes\cr \.{==}&|binop|: \.{\\E}&yes\cr \.{\&\&}&|binop|: \.{\\W}&yes\cr \.{\v\v}&|binop|: \.{\\V}&yes\cr \.{++}&|unop|: \.{\\PP}&yes\cr \.{--}&|unop|: \.{\\MM}&yes\cr \.{->}&|binop|: \.{\\MG}&yes\cr \.{>>}&|binop|: \.{\\GG}&yes\cr \.{<<}&|binop|: \.{\\LL}&yes\cr \.{::}&|colcol|: \.{\\DC}&maybe\cr \.{.*}&|binop|: \.{\\PA}&yes\cr \.{->*}&|binop|: \.{\\MGA}&yes\cr \.{...}&|raw_int|: \.{\\,\\ldots\\,}&yes\cr \."string\."&|exp|: \.{\\.\{}string with special characters quoted\.\}&maybe\cr \.{@@=}string\.{@@>}&|exp|: \.{\\vb\{}string with special characters quoted\.\}&maybe\cr \.{@@'7'}&|exp|: \.{\\.\{@@'7'\}}&maybe\cr \.{077} or \.{\\77}&|exp|: \.{\\T\{\\\~77\}}&maybe\cr \.{0x7f}&|exp|: \.{\\T\{\\\^7f\}}&maybe\cr \.{0b10111}&|exp|: \.{\\T\{\\\\10111\}}&maybe\cr \.{77}&|exp|: \.{\\T\{77\}}&maybe\cr \.{77L}&|exp|: \.{\\T\{77\\\$L\}}&maybe\cr \.{0.1E5}&|exp|: \.{\\T\{0.1\\\_5\}}&maybe\cr \.{0x10p3}&|exp|: \.{\\T\{\\\^10\}\\p\{3\}}&maybe\cr \.{1'000'000}&|exp|: \.{\\T\{1\\\ 000\\\ 000\}}&maybe\cr \.+&|ubinop|: \.+&yes\cr \.-&|ubinop|: \.-&yes\cr \.*&|raw_ubin|: \.*&yes\cr \./&|binop|: \./&yes\cr \.<&|prelangle|: \.{\\langle}&yes\cr \.=&|binop|: \.{\\K}&yes\cr \.>&|prerangle|: \.{\\rangle}&yes\cr \..&|binop|: \..&yes\cr \.{\v}&|binop|: \.{\\OR}&yes\cr \.\^&|binop|: \.{\\XOR}&yes\cr \.\%&|binop|: \.{\\MOD}&yes\cr \.?&|question|: \.{\\?}&yes\cr \.!&|unop|: \.{\\R}&yes\cr \.\~&|unop|: \.{\\CM}&yes\cr \.\&&|raw_ubin|: \.{\\AND}&yes\cr \.(&|lpar|: \.(&maybe\cr \.)&|rpar|: \.)&maybe\cr \.[&|lbrack|: \.[&maybe\cr \.]&|rbrack|: \.]&maybe\cr \.\{&|lbrace|: \.\{&yes\cr \.\}&|lbrace|: \.\}&yes\cr \.,&|comma|: \.,&yes\cr \.;&|semi|: \.;&maybe\cr \.:&|colon|: \.:&no\cr \.\# (within line)&|ubinop|: \.{\\\#}&yes\cr \.\# (at beginning)&|lproc|: |force| |preproc_line| \.{\\\#}&no\cr end of \.\# line&|rproc|: |force|&no\cr identifier&|exp|: \.{\\\\\{}identifier with underlines and dollar signs quoted\.\}&maybe\cr \.{alignas}&|alignas_like|: \stars&maybe\cr \.{alignof}&|sizeof_like|: \stars&maybe\cr \.{and}&|alfop|: \stars&yes\cr \.{and\_eq}&|alfop|: \stars&yes\cr \.{asm}&|sizeof_like|: \stars&maybe\cr \.{auto}&|int_like|: \stars&maybe\cr \.{bitand}&|alfop|: \stars&yes\cr \.{bitor}&|alfop|: \stars&yes\cr \.{bool}&|raw_int|: \stars&maybe\cr \.{break}&|case_like|: \stars&maybe\cr \.{case}&|case_like|: \stars&maybe\cr \.{catch}&|catch_like|: \stars&maybe\cr \.{char}&|raw_int|: \stars&maybe\cr \.{char8\_t}&|raw_int|: \stars&maybe\cr \.{char16\_t}&|raw_int|: \stars&maybe\cr \.{char32\_t}&|raw_int|: \stars&maybe\cr \.{class}&|struct_like|: \stars&maybe\cr \.{clock\_t}&|raw_int|: \stars&maybe\cr \.{compl}&|alfop|: \stars&yes\cr \.{complex}&|int_like|: \stars&yes\cr \.{concept}&|int_like|: \stars&maybe\cr 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\.{xor\_eq}&|alfop|: \stars&yes\cr \.{@@,}&|insert|: \.{\\,}&maybe\cr \.{@@\v}&|insert|: |opt| \.0&maybe\cr \.{@@/}&|insert|: |force|&no\cr \.{@@\#}&|insert|: |big_force|&no\cr \.{@@+}&|insert|: |big_cancel| \.{\{\}} |break_space| \.{\{\}} |big_cancel|&no\cr \.{@@;}&|semi|: &maybe\cr \.{@@[@q]@>}&|begin_arg|: &maybe\cr \.{@q[@>@@]}&|end_arg|: &maybe\cr \.{@@\&}&|insert|: \.{\\J}&maybe\cr \.{@@h}&|insert|: |force| \.{\\ATH} |force|&no\cr \.{@@<}\thinspace section name\thinspace\.{@@>}&|section_scrap|: \.{\\X}$n$\.:translated section name\.{\\X}&maybe\cr \.{@@(@q)@>}\thinspace section name\thinspace\.{@@>}&|section_scrap|: \.{\\X}$n$\.{:\\.\{}section name with special characters quoted\.{\\,\}\\X}\footnote*{The \.{\\,} (thin space) is omitted in ``|inner| \TeX\ mode.''}&maybe\cr \.{/*}\thinspace comment\thinspace\.{*/}&|insert|: |cancel| \.{\\C\{}translated comment\.\} |force|&no\cr \.{//}\thinspace comment&|insert|: |cancel| \.{\\SHC\{}translated comment\.\} |force|&no\cr } \smallskip The construction \.{@@t}\thinspace stuff\/\thinspace\.{@@>} contributes \.{\\hbox\{}\thinspace stuff\/\thinspace\.\} to the following scrap. @i prod.w @* Implementing the productions. More specifically, a scrap is a structure consisting of a category |cat| and a |text_pointer| |trans|, which points to the translation in |tok_start|. When \CEE/ text is to be processed with the grammar above, we form an array |scrap_info| containing the initial scraps. Our production rules have the nice property that the right-hand side is never longer than the left-hand side. Therefore it is convenient to use sequential allocation for the current sequence of scraps. Five pointers are used to manage the parsing: \yskip\hang |pp| is a pointer into |scrap_info|. We will try to match the category codes |pp->cat,@,@,(pp+1)->cat|$,\,\,\ldots\,$ to the left-hand sides of productions. \yskip\hang |scrap_base|, |lo_ptr|, |hi_ptr|, and |scrap_ptr| are such that the current sequence of scraps appears in positions |scrap_base| through |lo_ptr| and |hi_ptr| through |scrap_ptr|, inclusive, in the |cat| and |trans| arrays. Scraps located between |scrap_base| and |lo_ptr| have been examined, while those in positions |>=hi_ptr| have not yet been looked at by the parsing process. \yskip\noindent Initially |scrap_ptr| is set to the position of the final scrap to be parsed, and it doesn't change its value. The parsing process makes sure that |lo_ptr>=pp+3|, since productions have as many as four terms, by moving scraps from |hi_ptr| to |lo_ptr|. If there are fewer than |pp+3| scraps left, the positions up to |pp+3| are filled with blanks that will not match in any productions. Parsing stops when |pp==lo_ptr+1| and |hi_ptr==scrap_ptr+1|. Since the |scrap| structure will later be used for other purposes, we declare its second element as a union. @d trans trans_plus.Trans /* translation texts of scraps */ @= typedef struct { eight_bits cat; eight_bits mathness; union { text_pointer Trans;@+@t}\6{@> @@; } trans_plus; } scrap; typedef scrap *scrap_pointer; @ @d max_scraps 5000 /* number of tokens in \CEE/ texts being parsed */ @= static scrap scrap_info[max_scraps]; /* memory array for scraps */ static scrap_pointer scrap_info_end=scrap_info+max_scraps-1; /* end of |scrap_info| */ static scrap_pointer scrap_base; /* beginning of the current scrap sequence */ static scrap_pointer scrap_ptr; /* ending of the current scrap sequence */ static scrap_pointer max_scr_ptr; /* largest value assumed by |scrap_ptr| */ static scrap_pointer pp; /* current position for reducing productions */ static scrap_pointer lo_ptr; /* last scrap that has been examined */ static scrap_pointer hi_ptr; /* first scrap that has not been examined */ @ @= scrap_base=scrap_info+1; max_scr_ptr=scrap_ptr=scrap_info; @ Token lists in |@!tok_mem| are composed of the following kinds of items for \TEX/ output. \yskip\item{$\bullet$}Character codes and special codes like |force| and |math_rel| represent themselves; \item{$\bullet$}|id_flag+p| represents \.{\\\\\{{\rm identifier $p$}\}}; \item{$\bullet$}|res_flag+p| represents \.{\\\&\{{\rm identifier $p$}\}}; \item{$\bullet$}|section_flag+p| represents section name |p|; \item{$\bullet$}|tok_flag+p| represents token list number |p|; \item{$\bullet$}|inner_tok_flag+p| represents token list number |p|, to be translated without line-break controls. @d id_flag 10240 /* signifies an identifier */ @d res_flag (2*id_flag) /* signifies a reserved word */ @d section_flag (3*id_flag) /* signifies a section name */ @d tok_flag (4*id_flag) /* signifies a token list */ @d inner_tok_flag (5*id_flag) /* signifies a token list in `\pb' */ @= #ifdef DEBUG static void print_text(text_pointer p); #endif @ This function prints a token list for debugging; it is not used in |main| at this time. @c #ifdef DEBUG static void print_text( text_pointer p) { token_pointer j; /* index into |tok_mem| */ sixteen_bits r; /* remainder of token after the flag has been stripped off */ if (p>=text_ptr) printf("BAD"); else for (j=*p; j<*(p+1); j++) { r=*j%id_flag; switch (*j) { case id_flag: printf("\\\\{"@q}@>); print_id((name_dir+r)); putchar(@q{@>'}'); break; case res_flag: printf("\\&{"@q}@>); print_id((name_dir+r)); putchar(@q{@>'}'); break; case section_flag: putchar('<'); print_section_name((name_dir+r)); putchar('>'); break; case tok_flag: printf("[[%d]]",(int)r); break; case inner_tok_flag: printf("|[[%d]]|",(int)r); break; default: @@; } } update_terminal(); } #endif /* |DEBUG| */ @ @= switch (r) { case math_rel: printf("\\mathrel{"@q}@>); break; case big_cancel: printf("[ccancel]"); break; case cancel: printf("[cancel]"); break; case indent: printf("[indent]"); break; case outdent: printf("[outdent]"); break; case dindent: printf("[dindent]"); break; case backup: printf("[backup]"); break; case opt: printf("[opt]"); break; case break_space: printf("[break]"); break; case force: printf("[force]"); break; case big_force: printf("[fforce]"); break; case preproc_line: printf("[preproc]"); break; case quoted_char: j++; printf("[%o]",(unsigned int)*j); break; case end_translation: printf("[quit]"); break; case inserted: printf("[inserted]"); break; default: putchar((int)r); } @ The production rules listed above are embedded directly into \.{CWEAVE}, since it is easier to do this than to write an interpretive system that would handle production systems in general. Several macros are defined here so that the program for each production is fairly short. All of our productions conform to the general notion that some |k| consecutive scraps starting at some position |j| are to be replaced by a single scrap of some category |c| whose translation is composed from the translations of the disappearing scraps. After this production has been applied, the production pointer |pp| should change by an amount |d|. Such a production can be represented by the quadruple |(j,k,c,d)|. For example, the production `|exp@,comma@,exp| $\RA$ |exp|' would be represented by `|(pp,3,exp,-2)|'; in this case the pointer |pp| should decrease by 2 after the production has been applied, because some productions with |exp| in their second or third positions might now match, but no productions have |exp| in the fourth position of their left-hand sides. Note that the value of |d| is determined by the whole collection of productions, not by an individual one. The determination of |d| has been done by hand in each case, based on the full set of productions but not on the grammar of \CEE/ or on the rules for constructing the initial scraps. We also attach a serial number to each production, so that additional information is available when debugging. For example, the program below contains the statement `|reduce(pp,3,exp,-2,4)|' when it implements the production just mentioned. Before calling |reduce|, the program should have appended the tokens of the new translation to the |tok_mem| array. We commonly want to append copies of several existing translations, and macros are defined to simplify these common cases. For example, |big_app2(pp)| will append the translations of two consecutive scraps, |pp->trans| and |(pp+1)->trans|, to the current token list. If the entire new translation is formed in this way, we write `|squash(j,k,c,d,n)|' instead of `|reduce(j,k,c,d,n)|'. For example, `|squash(pp,3,exp,-2,3)|' is an abbreviation for `|big_app3(pp); reduce(pp,3,exp,-2,3)|'. A couple more words of explanation: Both |big_app| and |app| append a token (while |big_app1| to |big_app4| append the specified number of scrap translations) to the current token list. The difference between |big_app| and |app| is simply that |big_app| checks whether there can be a conflict between math and non-math tokens, and intercalates a `\.{\$}' token if necessary. When in doubt what to use, use |big_app|. @d app(a) *(tok_ptr++)=(token)(a) @# @d big_app2(a) big_app1(a);@+big_app1(a+1) @d big_app3(a) big_app2(a);@+big_app1(a+2) @d big_app4(a) big_app3(a);@+big_app1(a+3) @# @d big_app1_insert(p,c) big_app1(p);@+big_app(c);@+big_app1(p+1) @d big_app1_insert_str(p,s) big_app1(p);@+app_str(s);@+big_app1(p+1) @d big_app2_insert(p,c) big_app2(p);@+big_app(c);@+big_app2(p+2) @= static void app_str(const char *);@/ static void big_app(token);@/ static void big_app1(scrap_pointer); @ The |mathness| is an attribute of scraps that says whether they are to be printed in a math mode context or not. It is separate from the ``part of speech'' (the |cat|) because to make each |cat| have a fixed |mathness| (as in the original \.{WEAVE}) would multiply the number of necessary production rules. The low two bits (i.e., |mathness % 4|) control the left boundary. (We need two bits because we allow cases |yes_math|, |no_math| and |maybe_math|, which can go either way.) The next two bits (i.e., |mathness / 4|) control the right boundary. If we combine two scraps and the right boundary of the first has a different mathness from the left boundary of the second, we insert a \.{\$} in between. Similarly, if at printing time some irreducible scrap has a |yes_math| boundary the scrap gets preceded or followed by a~\.{\$}. The left boundary is |maybe_math| if and only if the right boundary is. @d no_math 2 /* should be in horizontal mode */ @d yes_math 1 /* should be in math mode */ @d maybe_math 0 /* works in either horizontal or math mode */ @= static int cur_mathness, init_mathness; @ The code below is an exact translation of the production rules into \CEE/, using such macros, and the reader should have no difficulty understanding the format by comparing the code with the symbolic productions as they were listed earlier. @d begin_math() if (cur_mathness==maybe_math) init_mathness=yes_math; else if (cur_mathness==no_math) app_str("${}") @d end_math() if (cur_mathness==maybe_math) init_mathness=no_math; else if (cur_mathness==yes_math) app_str("{}$") @c static void app_str( const char *s) { while (*s) app_tok(*s++); } static void big_app( token a) { if (a==' ' || (a>=big_cancel && a<=big_force) || a==dindent) /* non-math token */ { end_math(); cur_mathness=no_math; } else { begin_math(); cur_mathness=yes_math; } app(a); } static void big_app1( scrap_pointer a) { switch (a->mathness % 4) { /* left boundary */ case (no_math): end_math(); cur_mathness=a->mathness / 4; /* right boundary */ break; case (yes_math): begin_math(); cur_mathness=a->mathness / 4; /* right boundary */ break; case (maybe_math): /* no changes */ break; } app(tok_flag+(int)((a)->trans-tok_start)); } @ Let us consider the big switch for productions now, before looking at its context. We want to design the program so that this switch works, so we might as well not keep ourselves in suspense about exactly what code needs to be provided with a proper environment. @d cat1 (pp+1)->cat @d cat2 (pp+2)->cat @d cat3 (pp+3)->cat @d lhs_not_simple (pp->cat!=public_like && pp->cat!=semi && pp->cat!=prelangle && pp->cat!=prerangle @| && pp->cat!=template_like && pp->cat!=new_like && pp->cat!=new_exp && pp->cat!=ftemplate @| && pp->cat!=raw_ubin && pp->cat!=const_like && pp->cat!=raw_int && pp->cat!=operator_like) /* not a production with left side length 1 */ @= if (cat1==end_arg && lhs_not_simple) if (pp->cat==begin_arg) squash(pp,2,exp,-2,124); else squash(pp,2,end_arg,-1,125); else if (pp->cat==rbrack) reduce(pp,0,rpar,-3,130); else if (pp->cat==using_like) reduce(pp,0,int_like,-3,140); else if (cat1==insert) squash(pp,2,pp->cat,-2,0); else if (cat2==insert) squash(pp+1,2,(pp+1)->cat,-1,0); else if (cat3==insert) squash(pp+2,2,(pp+2)->cat,0,0); else switch (pp->cat) { case exp: @@; @+break; case lpar: @@; @+break; case unop: @@; @+break; case ubinop: @@; @+break; case binop: @@; @+break; case cast: @@; @+break; case sizeof_like: @@; @+break; case int_like: @@; @+break; case public_like: @@; @+break; case colcol: @@; @+break; case decl_head: @@; @+break; case decl: @@; @+break; case base: @@; @+break; case struct_like: @@; @+break; case struct_head: @@; @+break; case fn_decl: @@; @+break; case function: @@; @+break; case lbrace: @@; @+break; case if_like: @@; @+break; case else_like: @@; @+break; case else_head: @@; @+break; case if_clause: @@; @+break; case if_head: @@; @+break; case do_like: @@; @+break; case case_like: @@; @+break; case catch_like: @@; @+break; case tag: @@; @+break; case stmt: @@; @+break; case semi: @@; @+break; case lproc: @@; @+break; case section_scrap: @@; @+break; case insert: @@; @+break; case prelangle: @@; @+break; case prerangle: @@; @+break; case langle: @@; @+break; case template_like: @@; @+break; case new_like: @@; @+break; case new_exp: @@; @+break; case ftemplate: @@; @+break; case for_like: @@; @+break; case raw_ubin: @@; @+break; case const_like: @@; @+break; case raw_int: @@; @+break; case operator_like: @@; @+break; case typedef_like: @@; @+break; case delete_like: @@; @+break; case question: @@; @+break; case alignas_like: @@; @+break; case lbrack: @@; @+break; case attr_head: @@; @+break; case attr: @@; @+break; case default_like: @@; @+break; } pp++; /* if no match was found, we move to the right */ @ In \CEE/, new specifier names can be defined via |typedef|, and we want to make the parser recognize future occurrences of the identifier thus defined as specifiers. This is done by the procedure |make_reserved|, which changes the |ilk| of the relevant identifier. We first need a procedure to recursively seek the first identifier in a token list, because the identifier might be enclosed in parentheses, as when one defines a function returning a pointer. If the first identifier found is a keyword like `\&{case}', we return the special value |case_found|; this prevents underlining of identifiers in case labels. If the first identifier is the keyword `\&{operator}', we give up; users who want to index definitions of overloaded \CPLUSPLUS/ operators should say, for example, `\.{@@!@@\^\\\&\{operator\} \$+\{=\}\$@@>}' (or, more properly alpha\-betized, `\.{@@!@@:operator+=\}\{\\\&\{operator\} \$+\{=\}\$@@>}'). @d no_ident_found (token_pointer)0 /* distinct from any identifier token */ @d case_found (token_pointer)1 /* likewise */ @d operator_found (token_pointer)2 /* likewise */ @= static token_pointer find_first_ident(text_pointer);@/ static void make_reserved(scrap_pointer);@/ static void make_underlined(scrap_pointer);@/ static void underline_xref(name_pointer); @ @c static token_pointer find_first_ident( text_pointer p) { token_pointer q; /* token to be returned */ token_pointer j; /* token being looked at */ sixteen_bits r; /* remainder of token after the flag has been stripped off */ if (p>=text_ptr) confusion("find_first_ident"); for (j=*p; j<*(p+1); j++) { r=*j%id_flag; switch (*j/id_flag) { case 2: /* |res_flag| */ if (name_dir[r].ilk==case_like) return case_found; if (name_dir[r].ilk==operator_like) return operator_found; if (name_dir[r].ilk!=raw_int) break; @=/* else fall through */@>@; case 1: return j; case 4: case 5: /* |tok_flag| or |inner_tok_flag| */ if ((q=find_first_ident(tok_start+r))!=no_ident_found) return q; @=/* else fall through */@>@; default: ; /* char, |section_flag|, fall thru: move on to next token */ if (*j==inserted) return no_ident_found; /* ignore inserts */ else if (*j==qualifier) j++; /* bypass namespace qualifier */ } } return no_ident_found; } @ The scraps currently being parsed must be inspected for any occurrence of the identifier that we're making reserved; hence the |for| loop below. @c static void make_reserved( /* make the first identifier in |p->trans| like |int| */ scrap_pointer p) { sixteen_bits tok_value; /* the name of this identifier, plus its flag */ token_pointer tok_loc; /* pointer to |tok_value| */ if ((tok_loc=find_first_ident(p->trans))<=operator_found) return; /* this should not happen */ tok_value=*tok_loc; for (;p<=scrap_ptr; p==lo_ptr? p=hi_ptr: p++) if (p->cat==exp) if (**(p->trans)==tok_value) { p->cat=raw_int; **(p->trans)=tok_value%id_flag+res_flag; } (name_dir+(sixteen_bits)(tok_value%id_flag))->ilk=raw_int; *tok_loc=tok_value%id_flag+res_flag; } @ In the following situations we want to mark the occurrence of an identifier as a definition: when |make_reserved| is just about to be used; after a specifier, as in |char **argv|; before a colon, as in \\{found}:; and in the declaration of a function, as in \\{main}()$\{\ldots;\}$. This is accomplished by the invocation of |make_underlined| at appropriate times. Notice that, in the declaration of a function, we find out that the identifier is being defined only after it has been swallowed up by an |exp|. @c static void make_underlined( /* underline the entry for the first identifier in |p->trans| */ scrap_pointer p) { token_pointer tok_loc; /* where the first identifier appears */ if ((tok_loc=find_first_ident(p->trans))<=operator_found) return; /* this happens, for example, in |case found:| */ xref_switch=def_flag; underline_xref(*tok_loc%id_flag+name_dir); } @ We cannot use |new_xref| to underline a cross-reference at this point because this would just make a new cross-reference at the end of the list. We actually have to search through the list for the existing cross-reference. @c static void underline_xref( name_pointer p) { xref_pointer q=(xref_pointer)p->xref; /* pointer to cross-reference being examined */ xref_pointer r; /* temporary pointer for permuting cross-references */ sixteen_bits m; /* cross-reference value to be installed */ sixteen_bits n; /* cross-reference value being examined */ if (no_xref) return; m=section_count+xref_switch; while (q != xmem) { n=q->num; if (n==m) return; else if (m==n+def_flag) { q->num=m; return; } else if (n>=def_flag && nxlink; } @@; } @ We get to this section only when the identifier is one letter long, so it didn't get a non-underlined entry during phase one. But it may have got some explicitly underlined entries in later sections, so in order to preserve the numerical order of the entries in the index, we have to insert the new cross-reference not at the beginning of the list (namely, at |p->xref|), but rather right before |q|. @= append_xref(0); /* this number doesn't matter */ xref_ptr->xlink=(xref_pointer)p->xref; r=xref_ptr; update_node(p); while (r->xlink!=q) {r->num=r->xlink->num; r=r->xlink;} r->num=m; /* everything from |q| on is left undisturbed */ @ Now comes the code that tries to match each production starting with a particular type of scrap. Whenever a match is discovered, the |squash| or |reduce| function will cause the appropriate action to be performed. @= if (cat1==lbrace || cat1==int_like || cat1==decl) { make_underlined(pp); big_app(dindent); big_app1(pp); reduce(pp,1,fn_decl,0,1); } else if (cat1==unop) squash(pp,2,exp,-2,2); else if ((cat1==binop || cat1==ubinop) && cat2==exp) squash(pp,3,exp,-2,3); else if (cat1==comma && cat2==exp) { big_app2(pp); app(opt); app('9'); big_app1(pp+2); reduce(pp,3,exp,-2,4); } else if (cat1==lpar && cat2==rpar && cat3==colon) reduce(pp+3,0,base,0,5); else if (cat1==cast && cat2==colon) reduce(pp+2,0,base,0,5); else if (cat1==semi) squash(pp,2,stmt,-1,6); else if (cat1==colon) { make_underlined (pp); squash(pp,2,tag,-1,7); } else if (cat1==rbrace) reduce(pp,0,stmt,-1,8); else if (cat1==lpar && cat2==rpar && (cat3==const_like || cat3==case_like)) { big_app1_insert(pp+2,' '); reduce(pp+2,2,rpar,0,9); } else if (cat1==cast && (cat2==const_like || cat2==case_like)) { big_app1_insert(pp+1,' '); reduce(pp+1,2,cast,0,9); } else if (cat1==exp || cat1==cast) squash(pp,2,exp,-2,10); else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,142); } else if (cat1==colcol && cat2==int_like) squash(pp,3,int_like,-2,152); @ @= if ((cat1==exp||cat1==ubinop) && cat2==rpar) squash(pp,3,exp,-2,11); else if (cat1==rpar) { big_app1_insert_str(pp,"\\,"); @.\\,@> reduce(pp,2,exp,-2,12); } else if ((cat1==decl_head || cat1==int_like || cat1==cast) && cat2==rpar) squash(pp,3,cast,-2,13); else if ((cat1==decl_head || cat1==int_like || cat1==exp) && cat2==comma) { big_app3(pp); app(opt); app('9'); reduce(pp,3,lpar,-1,14); } else if (cat1==stmt || cat1==decl) { big_app2(pp); big_app(' '); reduce(pp,2,lpar,-1,15); } @ @= if (cat1==exp || cat1==int_like) squash(pp,2,exp,-2,16); @ @= if (cat1==cast && cat2==rpar) { big_app('{'); big_app1_insert(pp,'}'); reduce(pp,2,cast,-2,17); } else if (cat1==exp || cat1==int_like) { big_app('{'); big_app1_insert(pp,'}'); reduce(pp,2,cat1,-2,18); } else if (cat1==binop) { big_app(math_rel); big_app1_insert(pp,'{'); big_app('}'); big_app('}'); reduce(pp,2,binop,-1,19); } @ @= if (cat1==binop) { big_app(math_rel); big_app('{'); big_app1(pp); big_app('}'); big_app('{'); big_app1(pp+1); big_app('}'); big_app('}'); reduce(pp,2,binop,-1,20); } @ @= if (cat1==lpar) squash(pp,2,lpar,-1,21); else if (cat1==exp) { big_app1_insert_str(pp,"\\,"); @.\\,@> reduce(pp,2,exp,-2,21); } else if (cat1==semi) reduce(pp,0,exp,-2,22); @ @= if (cat1==cast) squash(pp,2,exp,-2,23); else if (cat1==exp) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,24); } @ @= if (cat1==int_like|| cat1==struct_like) { big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,25); } else if (cat1==exp && (cat2==raw_int||cat2==struct_like)) squash(pp,2,int_like,-2,26); else if (cat1==exp || cat1==ubinop || cat1==colon) { big_app1(pp); big_app(' '); reduce(pp,1,decl_head,-1,27); } else if (cat1==semi || cat1==binop) reduce(pp,0,decl_head,0,28); @ @= if (cat1==colon) squash(pp,2,tag,-1,29); else reduce(pp,0,int_like,-2,30); @ @= if (cat1==exp||cat1==int_like) { app(qualifier); squash(pp,2,cat1,-2,31); } else if (cat1==colcol) squash(pp,2,colcol,-1,32); @ @= if (cat1==comma) { big_app2(pp); app(opt); app('9'); reduce(pp,2,decl_head,-1,33); } else if (cat1==ubinop) { big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,decl_head,-1,34); } else if (cat1==exp && cat2!=lpar && cat2!=lbrack && cat2!=exp && cat2!=cast) { make_underlined(pp+1); squash(pp,2,decl_head,-1,35); } else if ((cat1==binop||cat1==colon) && cat2==exp && (cat3==comma || cat3==semi || cat3==rpar)) squash(pp,3,decl_head,-1,36); else if (cat1==cast) squash(pp,2,decl_head,-1,37); else if (cat1==int_like || cat1==lbrace || cat1==decl) { big_app(dindent); squash(pp,1,fn_decl,0,38); } else if (cat1==semi) squash(pp,2,decl,-1,39); else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,decl_head,-1,139); } @ @= if (cat1==decl) { big_app1_insert(pp,force); reduce(pp,2,decl,-1,40); } else if (cat1==stmt || cat1==function) { big_app1_insert(pp,big_force); reduce(pp,2,cat1,-1,41); } @ @= if (cat1==int_like || cat1==exp) { if (cat2==comma) { big_app1_insert(pp,' '); big_app1(pp+2); app(opt); app('9'); reduce(pp,3,base,0,42); } else if (cat2==lbrace) { big_app1_insert(pp,' '); big_app(' '); big_app1(pp+2); reduce(pp,3,lbrace,-2,43); } } @ @= if (cat1==lbrace) { big_app1_insert(pp,' '); reduce(pp,2,struct_head,0,44); } else if (cat1==exp||cat1==int_like) { if (cat2==lbrace || cat2==semi) { make_underlined(pp+1); make_reserved(pp+1); big_app1_insert(pp,' '); if (cat2==semi) reduce(pp,2,decl_head,0,45); else { big_app(' '); big_app1(pp+2); reduce(pp,3,struct_head,0,46); } } else if (cat2==colon) reduce(pp+2,0,base,2,47); else if (cat2!=base) { big_app1_insert(pp,' '); reduce(pp,2,int_like,-2,48); } } else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,struct_like,-3,141); } else if (cat1==struct_like) { big_app1_insert(pp,' '); reduce(pp,2,struct_like,-3,151); } @ @= if ((cat1==decl || cat1==stmt || cat1==function) && cat2==rbrace) { big_app1(pp); big_app(indent); big_app(force); big_app1(pp+1); big_app(outdent); big_app(force); big_app1(pp+2); reduce(pp,3,int_like,-2,49); } else if (cat1==rbrace) { big_app1_insert_str(pp,"\\,"); @.\\,@> reduce(pp,2,int_like,-2,50); } @ @= if (cat1==decl) { big_app1_insert(pp,force); reduce(pp,2,fn_decl,0,51); } else if (cat1==stmt) { big_app1(pp); app(outdent); app(outdent); big_app(force); big_app1(pp+1); reduce(pp,2,function,-1,52); } else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,fn_decl,0,157); } @ @= if (cat1==stmt || cat1==decl || cat1==function) { big_app1_insert(pp,big_force); reduce(pp,2,cat1,-1,53); } @ @= if (cat1==rbrace) { big_app1_insert_str(pp,"\\,"); @.\\,@> reduce(pp,2,stmt,-1,54); } else if ((cat1==stmt||cat1==decl||cat1==function) && cat2==rbrace) { big_app(force); big_app1(pp); big_app(indent); big_app(force); big_app1(pp+1); big_app(force); big_app(backup); big_app1(pp+2); big_app(outdent); big_app(force); reduce(pp,3,stmt,-1,55); } else if (cat1==exp) { if (cat2==rbrace) squash(pp,3,exp,-2,56); else if (cat2==comma && cat3==rbrace) squash(pp,4,exp,-2,56); } @ @= if (cat1==exp) { big_app1_insert(pp,' '); reduce(pp,2,if_clause,0,57); } @ @= if (cat1==colon) reduce(pp+1,0,base,1,58); else if (cat1==lbrace) reduce(pp,0,else_head,0,59); else if (cat1==stmt) { big_app(force); big_app1(pp); big_app(indent); big_app(break_space); big_app1(pp+1); big_app(outdent); big_app(force); reduce(pp,2,stmt,-1,60); } @ @= if (cat1==stmt || cat1==exp) { big_app(force); big_app1(pp); big_app(break_space); app(noop); big_app(cancel); big_app1(pp+1); big_app(force); reduce(pp,2,stmt,-1,61); } @ @= if (cat1==lbrace) reduce(pp,0,if_head,0,62); else if (cat1==stmt) { if (cat2==else_like) { big_app(force); big_app1(pp); big_app(indent); big_app(break_space); big_app1(pp+1); big_app(outdent); big_app(force); big_app1(pp+2); if (cat3==if_like) { big_app(' '); big_app1(pp+3); reduce(pp,4,if_like,0,63); } else reduce(pp,3,else_like,0,64); } else reduce(pp,0,else_like,0,65); } else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,if_head,0,146); } @ @= if (cat1==stmt || cat1==exp) { if (cat2==else_like) { big_app(force); big_app1(pp); big_app(break_space); app(noop); big_app(cancel); big_app1_insert(pp+1,force); if (cat3==if_like) { big_app(' '); big_app1(pp+3); reduce(pp,4,if_like,0,66); } else reduce(pp,3,else_like,0,67); } else reduce(pp,0,else_head,0,68); } @ @= if (cat1==stmt && cat2==else_like && cat3==semi) { big_app1(pp); big_app(break_space); app(noop); big_app(cancel); big_app1(pp+1); big_app(cancel); app(noop); big_app(break_space); big_app2(pp+2); reduce(pp,4,stmt,-1,69); } @ @= if (cat1==semi) squash(pp,2,stmt,-1,70); else if (cat1==colon) squash(pp,2,tag,-1,71); else if (cat1==exp) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,72); } @ @= if (cat1==cast || cat1==exp) { big_app1_insert(pp,dindent); reduce(pp,2,fn_decl,0,73); } @ @= if (cat1==tag) { big_app1_insert(pp,break_space); reduce(pp,2,tag,-1,74); } else if (cat1==stmt||cat1==decl||cat1==function) { big_app(force); big_app(backup); big_app1_insert(pp,break_space); reduce(pp,2,cat1,-1,75); } else if (cat1==rbrace) reduce(pp,0,decl,-1,156); @ The user can decide at run-time whether short statements should be grouped together on the same line. @d force_lines flags['f'] /* should each statement be on its own line? */ @= force_lines=true; @ @= if (cat1==stmt || cat1==decl || cat1==function) { big_app1_insert(pp, (cat1==decl || cat1==function) ? big_force : force_lines ? force : break_space); reduce(pp,2,cat1,-1,76); } @ @= big_app(' '); squash(pp,1,stmt,-1,77); @ @= if (cat1==define_like) make_underlined(pp+2); if (cat1==if_like || cat1==else_like || cat1==define_like) squash(pp,2,lproc,0,78); else if (cat1==rproc) { app(inserted); squash(pp,2,insert,-1,79); } else if (cat1==exp || cat1==function) { if (cat2==rproc) { app(inserted); big_app1_insert(pp,' '); big_app1(pp+2); reduce(pp,3,insert,-1,80); } else if (cat1==exp && cat2==exp && cat3==rproc) { app(inserted); big_app1_insert(pp,' '); app_str("\\5"); @.\\5@> big_app2(pp+2); reduce(pp,4,insert,-1,80); } } @ @= if (cat1==semi) { big_app2(pp); big_app(force); reduce(pp,2,stmt,-2,81); } else reduce(pp,0,exp,-2,82); @ @= if (cat1==function) squash(pp,2,function,0,83); @ @= init_mathness=cur_mathness=yes_math; app('<'); reduce(pp,1,binop,-2,84); @ @= init_mathness=cur_mathness=yes_math; app('>'); reduce(pp,1,binop,-2,85); @ @d reserve_typenames flags['t'] /* should we treat \&{typename} in a template like \&{typedef}? */ @= if (cat1==prerangle) { big_app1_insert_str(pp,"\\,"); @.\\,@> reduce(pp,2,cast,-1,86); } else if (cat1==decl_head || cat1==int_like || cat1==exp) { if (cat2==prerangle) squash(pp,3,cast,-1,87); else if (cat2==comma) { big_app3(pp); app(opt); app('9'); reduce(pp,3,langle,0,88); } } else if ((cat1==struct_like) @| && (cat2==exp || cat2==int_like) @| && (cat3==comma || cat3==prerangle)) { make_underlined(pp+2); if (reserve_typenames) make_reserved(pp+2); big_app2_insert(pp,' '); if (cat3==comma) { app(opt); app('9'); reduce(pp,4,langle,0,153); } else reduce(pp,4,cast,-1,154); } @ @= if (cat1==exp && cat2==prelangle) reduce(pp+2,0,langle,2,89); else if (cat1==exp || cat1==raw_int) { big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,90); } else if (cat1==cast && cat2==struct_like) { big_app1_insert(pp,' '); reduce(pp,2,struct_like,0,155); } else reduce(pp,0,raw_int,0,91); @ @= if (cat1==lpar && cat2==exp && cat3==rpar) squash(pp,4,new_like,0,92); else if (cat1==cast) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,93); } else if (cat1!=lpar) reduce(pp,0,new_exp,0,94); @ @= if (cat1==int_like || cat1==const_like) { big_app1_insert(pp,' '); reduce(pp,2,new_exp,0,95); } else if (cat1==struct_like && (cat2==exp || cat2==int_like)) { big_app1_insert(pp,' '); big_app(' '); big_app1(pp+2); reduce(pp,3,new_exp,0,96); } else if (cat1==raw_ubin) { big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,new_exp,0,97); } else if (cat1==lpar) reduce(pp,0,exp,-2,98); else if (cat1==exp) { big_app1(pp); big_app(' '); reduce(pp,1,exp,-2,98); } else if (cat1!=raw_int && cat1!=struct_like && cat1!=colcol) reduce(pp,0,exp,-2,99); @ @= if (cat1==prelangle) reduce(pp+1,0,langle,1,100); else reduce(pp,0,exp,-2,101); @ @= if (cat1==exp) { big_app1_insert(pp,' '); reduce(pp,2,else_like,-2,102); } @ @= if (cat1==const_like) { big_app2(pp); app_str("\\ "); reduce(pp,2,raw_ubin,0,103); @.\\\ @> } else reduce(pp,0,ubinop,-2,104); @ @= reduce(pp,0,int_like,-2,105); @ @= if (cat1==prelangle) reduce(pp+1,0,langle,1,106); else if (cat1==colcol) squash(pp,2,colcol,-1,107); else if (cat1==cast) squash(pp,2,raw_int,0,108); else if (cat1==lpar) reduce(pp,0,exp,-2,109); else if (cat1==lbrack) reduce(pp,0,exp,-2,144); else if (cat1!=langle) reduce(pp,0,int_like,-3,110); @ @= if (cat1==binop || cat1==unop || cat1==ubinop) { if (cat2==binop) break; big_app1_insert(pp,'{'); big_app('}'); reduce(pp,2,exp,-2,111); } else if (cat1==new_like || cat1==delete_like) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,112); } else if (cat1==comma) squash(pp,2,exp,-2,113); else if (cat1!=raw_ubin) reduce(pp,0,new_exp,0,114); @ @= if ((cat1==int_like || cat1==cast) && (cat2==comma || cat2==semi)) reduce(pp+1,0,exp,-1,115); else if (cat1==int_like) { big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,116); } else if (cat1==exp && cat2!=lpar && cat2!=lbrack && cat2!=exp && cat2!=cast) { make_underlined(pp+1); make_reserved(pp+1); big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,117); } else if (cat1==comma) squash(pp,2,typedef_like,0,118); else if (cat1==semi) squash(pp,2,decl,-1,119); else if (cat1==ubinop && (cat2==ubinop || cat2==cast)) { big_app('{'); big_app1_insert(pp+1,'}'); reduce(pp+1,2,cat2,0,120); } @ @= if (cat1==lbrack && cat2==rbrack) { big_app1(pp); big_app1_insert_str(pp+1,"\\,"); @.\\,@> reduce(pp,3,delete_like,0,121); } else if (cat1==exp) { big_app1_insert(pp,' '); reduce(pp,2,exp,-2,122); } @ @= if (cat1==exp && (cat2==colon || cat2==base)) { (pp+2)->mathness=5*yes_math; /* this colon should be in math mode */ squash(pp,3,binop,-2,123); } @ @= if (cat1==decl_head) squash(pp,2,attr,-1,126); else if (cat1==exp) squash(pp,2,attr,-1,127); else if (cat1==cast) squash(pp,2,attr,-1,158); @ @= if (cat1==lbrack) if (cat2==rbrack && cat3==rbrack) squash(pp,4,exp,-2,147); else squash(pp,2,attr_head,-1,128); else reduce(pp,0,lpar,-1,129); @ @= if (cat1==rbrack && cat2==rbrack) squash(pp,3,attr,-1,131); else if (cat1==exp) squash(pp,2,attr_head,0,132); else if (cat1==using_like && cat2==exp && cat3==colon) { big_app2_insert(pp,' '); big_app(' '); reduce(pp,4,attr_head,0,133); } else if (cat1==comma) squash(pp,2,attr_head,0,145); @ @= if (cat1==lbrace || cat1==stmt) { big_app1_insert(pp,' '); reduce(pp,2,cat1,-2,134); } else if (cat1==tag) { big_app1_insert(pp,' '); reduce(pp,2,tag,-1,135); } else if (cat1==semi) squash(pp,2,stmt,-2,136); else if (cat1==attr) { big_app1_insert(pp,' '); reduce(pp,2,attr,-1,137); } else if (cat1==decl_head) { big_app1_insert(pp,' '); reduce(pp,2,decl_head,-1,138); } else if (cat1==typedef_like) { big_app1_insert(pp,' '); reduce(pp,2,typedef_like,0,143); } else if (cat1==function) { big_app1_insert(pp,' '); reduce(pp,2,function,-1,148); } @ @= if (cat1==colon) reduce(pp,0,case_like,-3,149); else reduce(pp,0,exp,-2,150); @ The `|freeze_text|' macro is used to give official status to a token list. Before saying |freeze_text|, items are appended to the current token list, and we know that the eventual number of this token list will be the current value of |text_ptr|. But no list of that number really exists as yet, because no ending point for the current list has been stored in the |tok_start| array. After saying |freeze_text|, the old current token list becomes legitimate, and its number is the current value of |text_ptr-1| since |text_ptr| has been increased. The new current token list is empty and ready to be appended~to. Note that |freeze_text| does not check to see that |text_ptr| hasn't gotten too large, since it is assumed that this test was done beforehand. @d freeze_text() *(++text_ptr)=tok_ptr @= static void reduce(scrap_pointer,short,eight_bits,short,short);@/ static void squash(scrap_pointer,short,eight_bits,short,short); @ Now here's the |reduce| procedure used in our code for productions, which takes advantage of the simplifications that occur when |k==0| or |k==1|. @c static void reduce( scrap_pointer j, short k, eight_bits c, short d, short n) { scrap_pointer i; /* pointer into scrap memory */ j->cat=c; if (k>0) { j->trans=text_ptr; j->mathness=4*cur_mathness+init_mathness; freeze_text(); } if (k>1) { for (i=j+k; i<=lo_ptr; i++) *(i-k+1)=*i;@^system dependencies@> lo_ptr=lo_ptr-k+1; } pp=(pp+d@; pp--; /* we next say |pp++| */ } @ And here's the |squash| procedure, which combines |big_app|${}_k$ and |reduce| for matching numbers~|k|. @c static void squash( scrap_pointer j, short k, eight_bits c, short d, short n) { switch (k) { case 1: big_app1(j); break; case 2: big_app2(j); break; case 3: big_app3(j); break; case 4: big_app4(j); break; default: confusion("squash"); } reduce(j,k,c,d,n); } @ If \.{CWEAVE} is being run in debugging mode, the production numbers and current stack categories will be printed out when |tracing| is set to |fully|; a sequence of two or more irreducible scraps will be printed out when |tracing| is set to |partly|. @d off 0 @d partly 1 @d fully 2 @= static int tracing=off; /* can be used to show parsing details */ @ @= if (tracing==fully) { printf("\n%d:",n); for (i=scrap_base; i<=lo_ptr; i++) { putchar(i==pp?'*':' '); if (i->mathness %4 == yes_math) putchar('+'); else if (i->mathness %4 == no_math) putchar('-'); print_cat(i->cat); if (i->mathness /4 == yes_math) putchar('+'); else if (i->mathness /4 == no_math) putchar('-'); } if (hi_ptr<=scrap_ptr) printf("..."); /* indicate that more is coming */ } @ And here now is the code that applies productions as long as possible. Before applying the production mechanism, we must make sure it has good input (at least four scraps, the length of the lhs of the longest rules), and that there is enough room in the memory arrays to hold the appended tokens and texts. Here we use a very conservative test; it's more important to make sure the program will still work if we change the production rules (within reason) than to squeeze the last bit of space from the memory arrays. @d safe_tok_incr 20 @d safe_text_incr 10 @d safe_scrap_incr 10 @= while (true) { @@; if (tok_ptr+safe_tok_incr>tok_mem_end) { if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr; overflow("token"); } if (text_ptr+safe_text_incr>tok_start_end) { if (text_ptr>max_text_ptr) max_text_ptr=text_ptr; overflow("text"); } if (pp>lo_ptr) break; init_mathness=cur_mathness=maybe_math; @@; } @ If we get to the end of the scrap list, category codes equal to zero are stored, since zero does not match anything in a production. @= if (lo_ptr for (j=lo_ptr+1;j<=pp+3;j++) j->cat=0; } @ The |translate| function assumes that scraps have been stored in positions |scrap_base| through |scrap_ptr| of |cat| and |trans|. It applies productions as much as possible. The result is a token list containing the translation of the given sequence of scraps. After calling |translate|, we will have |text_ptr+3<=max_texts| and |tok_ptr+6<=max_toks|, so it will be possible to create up to three token lists with up to six tokens without checking for overflow. Before calling |translate|, we should have |text_ptr@; @@; @@; } @ @=@+static text_pointer translate(void); @ If the initial sequence of scraps does not reduce to a single scrap, we concatenate the translations of all remaining scraps, separated by blank spaces, with dollar signs surrounding the translations of scraps where appropriate. @= @@; for (j=scrap_base; j<=lo_ptr; j++) { if (j!=scrap_base) app(' '); if (j->mathness % 4 == yes_math) app('$'); app(tok_flag+(int)(j->trans-tok_start)); if (j->mathness / 4 == yes_math) app('$'); if (tok_ptr+6>tok_mem_end) overflow("token"); } freeze_text(); return text_ptr-1; @ @= if (lo_ptr>scrap_base && tracing==partly) { printf("\nIrreducible scrap sequence in section %d:",(int)section_count); @.Irreducible scrap sequence...@> mark_harmless(); for (j=scrap_base; j<=lo_ptr; j++) { putchar(' '); print_cat(j->cat); } } @ @= if (tracing==fully) { printf("\nTracing after l. %d:\n",cur_line); mark_harmless(); @.Tracing after...@> if (loc>buffer+50) { printf("..."); term_write(loc-51,51); } else term_write(buffer,loc-buffer); } @* Initializing the scraps. If we are going to use the powerful production mechanism just developed, we must get the scraps set up in the first place, given a \CEE/ text. A table of the initial scraps corresponding to \CEE/ tokens appeared above in the section on parsing; our goal now is to implement that table. We shall do this by implementing a subroutine called |C_parse| that is analogous to the |C_xref| routine used during phase one. Like |C_xref|, the |C_parse| procedure starts with the current value of |next_control| and it uses the operation |next_control=get_next()| repeatedly to read \CEE/ text until encountering the next `\.{\v}' or `\.{/*}', or until |next_control>=format_code|. The scraps corresponding to what it reads are appended into the |cat| and |trans| arrays, and |scrap_ptr| is advanced. @c static void C_parse( /* creates scraps from \CEE/ tokens */ eight_bits spec_ctrl) { while (next_control@; next_control=get_next(); if (next_control=='|' || next_control==begin_comment || next_control==begin_short_comment) return; } } @ @=@+static void C_parse(eight_bits); @ The following macro is used to append a scrap whose tokens have just been appended: @d app_scrap(c,b) { (++scrap_ptr)->cat=(c); scrap_ptr->trans=text_ptr; scrap_ptr->mathness=5*(b); /* no no, yes yes, or maybe maybe */ freeze_text(); } @ @= @@; switch (next_control) { case section_name: app(section_flag+(int)(cur_section-name_dir)); app_scrap(section_scrap,maybe_math);@+ app_scrap(exp,yes_math);@+break; case string: case constant: case verbatim: @@;@+break; case identifier: app_cur_id(true);@+break; case TeX_string: @@;@+break; case '/': case '.': app(next_control);@+app_scrap(binop,yes_math);@+break; case '<': app_str("\\langle");@+app_scrap(prelangle,yes_math);@+break; @.\\langle@> case '>': app_str("\\rangle");@+app_scrap(prerangle,yes_math);@+break; @.\\rangle@> case '=': app_str("\\K");@+app_scrap(binop,yes_math);@+break; @.\\K@> case '|': app_str("\\OR");@+app_scrap(binop,yes_math);@+break; @.\\OR@> case '^': app_str("\\XOR");@+app_scrap(binop,yes_math);@+break; @.\\XOR@> case '%': app_str("\\MOD");@+app_scrap(binop,yes_math);@+break; @.\\MOD@> case '!': app_str("\\R");@+app_scrap(unop,yes_math);@+break; @.\\R@> case '~': app_str("\\CM");@+app_scrap(unop,yes_math);@+break; @.\\CM@> case '+': case '-': app(next_control);@+app_scrap(ubinop,yes_math);@+break; case '*': app(next_control);@+app_scrap(raw_ubin,yes_math);@+break; case '&': app_str("\\AND");@+app_scrap(raw_ubin,yes_math);@+break; @.\\AND@> case '?': app_str("\\?");@+app_scrap(question,yes_math);@+break; @.\\?@> case '#': app_str("\\#");@+app_scrap(ubinop,yes_math);@+break; @.\\\#@> case ignore: case xref_roman: case xref_wildcard: case xref_typewriter: case noop:@+break; case '(': app(next_control);@+app_scrap(lpar,maybe_math);@+break; case ')': app(next_control);@+app_scrap(rpar,maybe_math);@+break; case '[': app(next_control);@+app_scrap(lbrack,maybe_math);@+break; case ']': app(next_control);@+app_scrap(rbrack,maybe_math);@+break; case '{': app_str("\\{"@q}@>);@+app_scrap(lbrace,yes_math);@+break; @.\\\{@>@q}@> case '}': app_str(@q{@>"\\}");@+app_scrap(rbrace,yes_math);@+break; @q{@>@.\\\}@> case ',': app(',');@+app_scrap(comma,yes_math);@+break; case ';': app(';');@+app_scrap(semi,maybe_math);@+break; case ':': app(':');@+app_scrap(colon,no_math);@+break;@/ @t\4@> @@; case thin_space: app_str("\\,");@+app_scrap(insert,maybe_math);@+break; @.\\,@> case math_break: app(opt);@+app('0');@+ app_scrap(insert,maybe_math);@+break; case line_break: app(force);@+app_scrap(insert,no_math);@+break; case left_preproc: app(force);@+app(preproc_line);@+app_str("\\#"); app_scrap(lproc,no_math);@+break; @.\\\#@> case right_preproc: app(force);@+app_scrap(rproc,no_math);@+break; case big_line_break: app(big_force);@+app_scrap(insert,no_math);@+break; case no_line_break: app(big_cancel);@+app(noop);@+app(break_space);@+ app(noop);@+app(big_cancel); app_scrap(insert,no_math);@+break; case pseudo_semi: app_scrap(semi,maybe_math);@+break; case macro_arg_open: app_scrap(begin_arg,maybe_math);@+break; case macro_arg_close: app_scrap(end_arg,maybe_math);@+break; case join: app_str("\\J");@+app_scrap(insert,no_math);@+break; @.\\J@> case output_defs_code: app(force);@+app_str("\\ATH");@+app(force); app_scrap(insert,no_math);@+break; @.\\ATH@> default: app(inserted);@+app(next_control); app_scrap(insert,maybe_math);@+break; } @ @= if (scrap_ptr+safe_scrap_incr>scrap_info_end || tok_ptr+safe_tok_incr>tok_mem_end @| || text_ptr+safe_text_incr>tok_start_end) { if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr; if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr; if (text_ptr>max_text_ptr) max_text_ptr=text_ptr; overflow("scrap/token/text"); } @ Some nonstandard characters may have entered \.{CWEAVE} by means of standard ones. They are converted to \TEX/ control sequences so that it is possible to keep \.{CWEAVE} from outputting unusual |char| codes. @=@t\1\quad@> case non_eq: app_str("\\I");@+app_scrap(binop,yes_math);@+break; @.\\I@> case lt_eq: app_str("\\Z");@+app_scrap(binop,yes_math);@+break; @.\\Z@> case gt_eq: app_str("\\G");@+app_scrap(binop,yes_math);@+break; @.\\G@> case eq_eq: app_str("\\E");@+app_scrap(binop,yes_math);@+break; @.\\E@> case and_and: app_str("\\W");@+app_scrap(binop,yes_math);@+break; @.\\W@> case or_or: app_str("\\V");@+app_scrap(binop,yes_math);@+break; @.\\V@> case plus_plus: app_str("\\PP");@+app_scrap(unop,yes_math);@+break; @.\\PP@> case minus_minus: app_str("\\MM");@+app_scrap(unop,yes_math);@+break; @.\\MM@> case minus_gt: app_str("\\MG");@+app_scrap(binop,yes_math);@+break; @.\\MG@> case gt_gt: app_str("\\GG");@+app_scrap(binop,yes_math);@+break; @.\\GG@> case lt_lt: app_str("\\LL");@+app_scrap(binop,yes_math);@+break; @.\\LL@> case dot_dot_dot: app_str("\\,\\ldots\\,");@+app_scrap(raw_int,yes_math); @+break; @.\\,@> @.\\ldots@> case colon_colon: app_str("\\DC");@+app_scrap(colcol,maybe_math);@+break; @.\\DC@> case period_ast: app_str("\\PA");@+app_scrap(binop,yes_math);@+break; @.\\PA@> case minus_gt_ast: app_str("\\MGA");@+app_scrap(binop,yes_math);@+break; @.\\MGA@> @ The following code must use |app_tok| instead of |app| in order to protect against overflow. Note that |tok_ptr+1<=max_toks| after |app_tok| has been used, so another |app| is legitimate before testing again. Many of the special characters in a string must be prefixed by `\.\\' so that \TEX/ will print them properly. @^special string characters@> @={@+ int count=-1; /* characters remaining before string break */ switch (next_control) { case constant: app_str("\\T{"@q}@>); break; @.\\T@> case string: count=20; app_str("\\.{"@q}@>); break; @.\\.@> default: app_str("\\vb{"@q}@>); @.\\vb@> } while (id_first@q{@>"}\\)\\.{"@q}@>); count=20; @q(@>@.\\)@> } switch (*id_first) { case ' ':case '\\':case '#':case '$':case '^':case '{':case '}': case '~':case '&':case '_': app('\\'); break; @.\\\ @> @.\\\\@> @.\\\#@> @.\\\$@> @.\\\^@> @.\\\{@>@q}@> @q{@>@.\\\}@> @.\\\~@> @.\\\&@> @.\\\_@> case '%': if (next_control==constant) { app_str("}\\p{"); /* special macro for `hex exponent' */ id_first++; /* skip |'%'| */ } else app('\\'); break; @.\\p@> @.\\\%@> case '@@': if (*(id_first+1)=='@@') id_first++; else err_print("! Double @@ should be used in strings"); @.Double @@ should be used...@> break; default: /* high-bit character handling */ @^high-bit character handling@> if((eight_bits)(*id_first)>0177) app_tok(quoted_char)@t;@>@; } app_tok(*id_first++); count--; } app(@q{@>'}'); app_scrap(exp,maybe_math); } @ We do not make the \TEX/ string into a scrap, because there is no telling what the user will be putting into it; instead we leave it open, to be picked up by the next scrap. If it comes at the end of a section, it will be made into a scrap when |finish_C| is called. There's a known bug here, in cases where an adjacent scrap is |prelangle| or |prerangle|. Then the \TEX/ string can disappear when the \.{\\langle} or \.{\\rangle} becomes \.{<} or \.{>}. For example, if the user writes \.{\v x<@@ty@@><42\v}, the \TEX/ string \.{\\hbox\{y\}} eventually becomes part of an |insert| scrap, which is combined with a |prelangle| scrap and eventually lost. The best way to work around this bug is probably to enclose the \.{@@t...@@>} in \.{@@[...@@]} so that the \TEX/ string is treated as an expression. @^bug, known@> @= app_str("\\hbox{"@q}@>); @^high-bit character handling@> while (id_first0177) app_tok(quoted_char)@t;@>@; else if (*id_first=='@@') id_first++; app_tok(*id_first++); } app(@q{@>'}'); @ The function |app_cur_id| appends the current identifier to the token list; it also builds a new scrap if |scrapping==true|. @= static void app_cur_id(boolean);@/ static text_pointer C_translate(void);@/ static void outer_parse(void); @ @c static void app_cur_id( boolean scrapping) /* are we making this into a scrap? */ { name_pointer p=id_lookup(id_first,id_loc,normal); if (p->ilk<=custom) { /* not a reserved word */ app(id_flag+(int)(p-name_dir)); if (scrapping) app_scrap(p->ilk==func_template? ftemplate: exp, p->ilk==custom? yes_math: maybe_math); @.\\NULL@> } else { app(res_flag+(int)(p-name_dir)); if (scrapping) { if (p->ilk==alfop) app_scrap(ubinop,yes_math)@t;@>@; else app_scrap(p->ilk,maybe_math); } } } @ When the `\.{\v}' that introduces \CEE/ text is sensed, a call on |C_translate| will return a pointer to the \TEX/ translation of that text. If scraps exist in |scrap_info|, they are unaffected by this translation process. @c static text_pointer C_translate(void) { text_pointer p; /* points to the translation */ scrap_pointer save_base=scrap_base; /* holds original value of |scrap_base| */ scrap_base=scrap_ptr+1; C_parse(section_name); /* get the scraps together */ if (next_control!='|') err_print("! Missing '|' after C text"); @.Missing '|'...@> app_tok(cancel); app_scrap(insert,maybe_math); /* place a |cancel| token as a final ``comment'' */ p=translate(); /* make the translation */ if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr; scrap_ptr=scrap_base-1; scrap_base=save_base; /* scrap the scraps */ return p; } @ The |outer_parse| routine is to |C_parse| as |outer_xref| is to |C_xref|: It constructs a sequence of scraps for \CEE/ text until |next_control>=format_code|. Thus, it takes care of embedded comments. The token list created from within `\pb' brackets is output as an argument to \.{\\PB}. Although \.{cwebmac} ignores \.{\\PB}, other macro packages might use it to localize the special meaning of the macros that mark up program text. @d make_pb flags['e'] @= make_pb=true; @ @c static void outer_parse(void) /* makes scraps from \CEE/ tokens and comments */ { int bal; /* brace level in comment */ text_pointer p, q; /* partial comments */ while (next_control@; app(cancel); app(inserted); if (is_long_comment) app_str("\\C{"@q}@>); @.\\C@> else app_str("\\SHC{"@q}@>); @.\\SHC@> bal=copy_comment(is_long_comment,1); next_control=ignore; while (bal>0) { p=text_ptr; freeze_text(); q=C_translate(); /* at this point we have |tok_ptr+6<=max_toks| */ app(tok_flag+(int)(p-tok_start)); if (make_pb) app_str("\\PB{"); @.\\PB@> app(inner_tok_flag+(int)(q-tok_start)); if (make_pb) app_tok('}'); if (next_control=='|') { bal=copy_comment(is_long_comment,bal); next_control=ignore; } else bal=0; /* an error has been reported */ } app(force); app_scrap(insert,no_math); /* the full comment becomes a scrap */ } } @* Output of tokens. So far our programs have only built up multi-layered token lists in \.{CWEAVE}'s internal memory; we have to figure out how to get them into the desired final form. The job of converting token lists to characters in the \TEX/ output file is not difficult, although it is an implicitly recursive process. Four main considerations had to be kept in mind when this part of \.{CWEAVE} was designed. (a) There are two modes of output: |outer| mode, which translates tokens like |force| into line-breaking control sequences, and |inner| mode, which ignores them except that blank spaces take the place of line breaks. (b) The |cancel| instruction applies to adjacent token or tokens that are output, and this cuts across levels of recursion since `|cancel|' occurs at the beginning or end of a token list on one level. (c) The \TEX/ output file will be semi-readable if line breaks are inserted after the result of tokens like |break_space| and |force|. (d) The final line break should be suppressed, and there should be no |force| token output immediately after `\.{\\Y\\B}'. @ The output process uses a stack to keep track of what is going on at different ``levels'' as the token lists are being written out. Entries on this stack have three parts: \yskip\hang |end_field| is the |tok_mem| location where the token list of a particular level will end; \yskip\hang |tok_field| is the |tok_mem| location from which the next token on a particular level will be read; \yskip\hang |mode_field| is the current mode, either |inner| or |outer|. \yskip\noindent The current values of these quantities are referred to quite frequently, so they are stored in an extra slot at the very end of the |stack| array. We call the current values |cur_end|, |cur_tok|, and |cur_mode|. The global variable |stack_ptr| tells how many levels of output are currently in progress. The end of output occurs when an |end_translation| token is found, so the stack is never empty except when we first begin the output process. @s mode int @= typedef enum { @!inner, /* value of |mode| for \CEE/ texts within \TEX/ texts */ @!outer /* value of |mode| for \CEE/ texts in sections */ } mode; typedef struct { token_pointer end_field; /* ending location of token list */ token_pointer tok_field; /* present location within token list */ mode mode_field; /* interpretation of control tokens */ } output_state; typedef output_state *stack_pointer; @ @d stack_size 2000 /* number of simultaneous output levels */ @d cur_state stack[stack_size] /* |cur_end|, |cur_tok|, |cur_mode| */ @d cur_end cur_state.end_field /* current ending location in |tok_mem| */ @d cur_tok cur_state.tok_field /* location of next output token in |tok_mem| */ @d cur_mode cur_state.mode_field /* current mode of interpretation */ @d init_stack() stack_ptr=stack;cur_mode=outer /* initialize the stack */ @= static output_state stack[stack_size+1]; /* info for non-current levels */ static stack_pointer stack_end=stack+stack_size-1; /* end of |stack| */ static stack_pointer stack_ptr; /* first unused location in the output state stack */ static stack_pointer max_stack_ptr; /* largest value assumed by |stack_ptr| */ @ @= max_stack_ptr=stack; @ @= static void push_level(text_pointer); @ To insert token-list |p| into the output, the |push_level| subroutine is called; it saves the old level of output and gets a new one going. The value of |cur_mode| is not changed. @c static void push_level( /* suspends the current level */ text_pointer p) { if (stack_ptr==stack_end) overflow("stack"); if (stack_ptr>stack) /* save current state */ *stack_ptr = cur_state;@^system dependencies@> stack_ptr++; if (stack_ptr>max_stack_ptr) max_stack_ptr=stack_ptr; cur_tok=*p; cur_end=*(p+1); } @ Conversely, the |pop_level| routine restores the conditions that were in force when the current level was begun. This subroutine will never be called when |stack_ptr==1|. It is so simple, we declare it as a macro: @d pop_level() cur_state = *(--stack_ptr)@^system dependencies@> @ The |get_output| function returns the next byte of output that is not a reference to a token list. It returns the values |identifier| or |res_word| or |section_code| if the next token is to be an identifier (typeset in italics), a reserved word (typeset in boldface), or a section name (typeset by a complex routine that might generate additional levels of output). In these cases |cur_name| points to the identifier or section name in question. @= static name_pointer cur_name; @ @d res_word 0201 /* returned by |get_output| for reserved words */ @d section_code 0200 /* returned by |get_output| for section names */ @= static eight_bits get_output(void);@/ static void output_C(void);@/ static void make_output(void); @ @c static eight_bits get_output(void) /* returns the next token of output */ { sixteen_bits a; /* current item read from |tok_mem| */ restart: while (cur_tok==cur_end) pop_level(); a=*(cur_tok++); if (a>=0400) { cur_name=a % id_flag + name_dir; switch (a / id_flag) { case 2: return res_word ; /* |a==res_flag+cur_name| */ case 3: return section_code ; /* |a==section_flag+cur_name| */ case 4: push_level(a % id_flag + tok_start); goto restart; /* |a==tok_flag+cur_name| */ case 5: push_level(a % id_flag + tok_start); cur_mode=inner; goto restart; /* |a==inner_tok_flag+cur_name| */ default: return identifier; /* |a==id_flag+cur_name| */ } } return (eight_bits)a; } @ The real work associated with token output is done by |make_output|. This procedure appends an |end_translation| token to the current token list, and then it repeatedly calls |get_output| and feeds characters to the output buffer until reaching the |end_translation| sentinel. It is possible for |make_output| to be called recursively, since a section name may include embedded \CEE/ text; however, the depth of recursion never exceeds one level, since section names cannot be inside of section names. A procedure called |output_C| does the scanning, translation, and output of \CEE/ text within `\pb' brackets, and this procedure uses |make_output| to output the current token list. Thus, the recursive call of |make_output| actually occurs when |make_output| calls |output_C| while outputting the name of a section. @^recursion@> @c static void output_C(void) /* outputs the current token list */ { token_pointer save_tok_ptr=tok_ptr; text_pointer save_text_ptr=text_ptr; sixteen_bits save_next_control=next_control; /* values to be restored */ text_pointer p; /* translation of the \CEE/ text */ next_control=ignore; p=C_translate(); app(inner_tok_flag+(int)(p-tok_start)); if (make_pb) out_str("\\PB{"); @.\\PB@> make_output(); /* output the list */ if (make_pb) out('}'); if (text_ptr>max_text_ptr) max_text_ptr=text_ptr; if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr; text_ptr=save_text_ptr; tok_ptr=save_tok_ptr; /* forget the tokens */ next_control=save_next_control; /* restore |next_control| to original state */ } @ Here is \.{CWEAVE}'s major output handler. @c static void make_output(void) /* outputs the equivalents of tokens */ { eight_bits a=0; /* current output byte */ eight_bits b; /* next output byte */ int c; /* count of |indent| and |outdent| tokens */ char scratch[longest_name+1]; /* scratch area for section names */ char *k, *k_limit; /* indices into |scratch| */ char *j; /* index into |buffer| */ char *p; /* index into |byte_mem| */ char delim; /* first and last character of string being copied */ char *save_loc, *save_limit; /* |loc| and |limit| to be restored */ name_pointer cur_section_name; /* name of section being output */ boolean save_mode; /* value of |cur_mode| before a sequence of breaks */ boolean dindent_pending=false; /* should a |dindent| be output? */ app(end_translation); /* append a sentinel */ freeze_text(); push_level(text_ptr-1); while (true) { a=get_output(); reswitch: switch(a) { case end_translation: return; case identifier: case res_word: @@; break; case section_code: @@; break; case math_rel: out_str("\\MRL{"@q}@>); @=/* fall through */@>@; @.\\MRL@> case noop: case inserted: break; case cancel: case big_cancel: c=0; b=a; while (true) { a=get_output(); if (a==inserted) continue; if ((abig_force && a!=dindent)) break; switch (a) { case dindent: c++; @=/* fall through */@>@; case indent: c++; break; case outdent: c--; break; case opt: a=get_output(); } } @@; goto reswitch; case dindent: a=get_output(); if (a!=big_force) { out_str("\\1\\1"); goto reswitch; } else dindent_pending=true; @=/* fall through */@>@; case indent: case outdent: case opt: case backup: case break_space: case force: case big_force: case preproc_line: @@; break; case quoted_char: out(*(cur_tok++)); @=/* fall through */@>@; case qualifier: break; default: out(a); /* otherwise |a| is an ordinary character */ } } } @ An identifier of length one does not have to be enclosed in braces, and it looks slightly better if set in a math-italic font instead of a (slightly narrower) text-italic font. Thus we output `\.{\\\v}\.{a}' but `\.{\\\\\{aa\}}'. @= out('\\'); if (a==identifier) { if (cur_name->ilk==custom && !doing_format) { custom_out: for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++) out(*p=='_'? 'x': *p=='$'? 'X': *p); break; } else if (is_tiny(cur_name)) out('|')@t;@>@; @.\\|@> else { delim='.'; for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++) if (xislower(*p)) { /* not entirely uppercase */ delim='\\'; break; } out(delim); } @.\\\\@> @.\\.@> } else if (cur_name->ilk==alfop) { out('X'); goto custom_out; } else out('&'); /* |a==res_word| */ @.\\\&@> if (is_tiny(cur_name)) { if (isxalpha((cur_name->byte_start)[0])) out('\\'); out((cur_name->byte_start)[0]); } else out_name(cur_name,true); @ The current mode does not affect the behavior of \.{CWEAVE}'s output routine except when we are outputting control tokens. @= if (a @.\\2@> @.\\3@> @.\\4@> @.\\8@> if (a==opt) { b=get_output(); /* |opt| is followed by a digit */ if (b!='0' || force_lines==false) out(b)@t;@>@; else out_str("{-1}"); /* |force_lines| encourages more \.{@@\v} breaks */ } } else if (a==opt) b=get_output(); /* ignore digit following |opt| */ } else @ @ If several of the tokens |break_space|, |force|, |big_force| occur in a row, possibly mixed with blank spaces (which are ignored), the largest one is used. A line break also occurs in the output file, except at the very end of the translation. The very first line break is suppressed (i.e., a line break that follows `\.{\\Y\\B}'). @= { b=a; save_mode=cur_mode; if (dindent_pending) { c=2; dindent_pending=false; } else c=0; while (true) { a=get_output(); if (a==inserted) continue; if (a==cancel || a==big_cancel) { @@; goto reswitch; /* |cancel| overrides everything */ } if ((a!=' ' && abig_force) { if (save_mode==outer) { if (out_ptr>out_buf+3 && strncmp(out_ptr-3,"\\Y\\B",4)==0) goto reswitch; @@; out('\\'); out(b-cancel+'0'); @.\\5@> @.\\6@> @.\\7@> if (a!=end_translation) finish_line(); } else if (a!=end_translation && cur_mode==inner) out(' '); goto reswitch; } if (a==indent) c++; else if (a==outdent) c--; else if (a==opt) a=get_output(); else if (a>b) b=a; /* if |a==' '| we have |a= for (;c>0;c--) out_str("\\1"); @.\\1@> for (;c<0;c++) out_str("\\2"); @.\\2@> @ The remaining part of |make_output| is somewhat more complicated. When we output a section name, we may need to enter the parsing and translation routines, since the name may contain \CEE/ code embedded in \pb\ constructions. This \CEE/ code is placed at the end of the active input buffer and the translation process uses the end of the active |tok_mem| area. @= out_str("\\X"); @.\\X@> cur_xref=(xref_pointer)cur_name->xref; if ((an_output=(cur_xref->num==file_flag))==true) cur_xref=cur_xref->xlink; if (cur_xref->num>=def_flag) { out_section(cur_xref->num-def_flag); if (phase==3) { cur_xref=cur_xref->xlink; while (cur_xref->num>=def_flag) { out_str(", "); out_section(cur_xref->num-def_flag); cur_xref=cur_xref->xlink; } } } else out('0'); /* output the section number, or zero if it was undefined */ out(':'); if (an_output) out_str("\\.{"@q}@>); @.\\.@> @@; if (an_output) cur_mode==inner?out_str(@q{@>"}"):out_str(@q{@>"\\,}"); out_str("\\X"); @ @= sprint_section_name(scratch,cur_name); k=scratch; k_limit=scratch+strlen(scratch); cur_section_name=cur_name; while (k@; if (an_output) switch (b) { case ' ': case '\\': case '#': case '%': case '$': case '^': case '{': case '}': case '~': case '&': case '_': out('\\'); @=/* falls through */@>@; @.\\\ @> @.\\\\@> @.\\\#@> @.\\\%@> @.\\\$@> @.\\\^@> @.\\\{@>@q}@> @q{@>@.\\\}@> @.\\\~@> @.\\\&@> @.\\\_@> default: out(b); } else if (b!='|') out(b)@t;@>@; else { @@; save_loc=loc; save_limit=limit; loc=limit+2; limit=j+1; *limit='|'; output_C(); loc=save_loc; limit=save_limit; } } @ @= if (*k++!='@@') { printf("%s","\n! Illegal control code in section name: <"); @.Illegal control code...@> print_section_name(cur_section_name); printf("> "); mark_error(); } @ The \CEE/ text enclosed in \pb\ should not contain `\.{\v}' characters, except within strings. We put a `\.{\v}' at the front of the buffer, so that an error message that displays the whole buffer will look a little bit sensible. The variable |delim| is zero outside of strings, otherwise it equals the delimiter that began the string being copied. @= j=limit+1; *j='|'; delim=0; while (true) { if (k>=k_limit) { printf("%s","\n! C text in section name didn't end: <"); @.C text...didn't end@> print_section_name(cur_section_name); printf("> "); mark_error(); break; } b=*(k++); if (b=='@@' || (b=='\\' && delim!=0)) @@; else { if (b=='\'' || b=='"') { if (delim==0) delim=b; else if (delim==b) delim=0; } if (b!='|' || delim!=0) { if (j>buffer+long_buf_size-3) overflow("buffer"); *(++j)=b; } else break; } } @ @= { if (j>buffer+long_buf_size-4) overflow("buffer"); *(++j)=b; *(++j)=*(k++); } @** Phase two processing. We have assembled enough pieces of the puzzle in order to be ready to specify the processing in \.{CWEAVE}'s main pass over the source file. Phase two is analogous to phase one, except that more work is involved because we must actually output the \TEX/ material instead of merely looking at the \.{CWEB} specifications. @c static void phase_two(void) { phase=2; reset_input(); if (show_progress) printf("%s","\nWriting the output file..."); @.Writing the output file...@> section_count=0; format_visible=true; copy_limbo(); finish_line(); flush_buffer(out_buf,false,false); /* insert a blank line, it looks nice */ while (!input_has_ended) @@; } @ @=@+static void phase_two(void); @ The output file will contain the control sequence \.{\\Y} between non-null sections of a section, e.g., between the \TEX/ and definition parts if both are nonempty. This puts a little white space between the parts when they are printed. However, we don't want \.{\\Y} to occur between two definitions within a single section. The variables |out_line| or |out_ptr| will change if a section is non-null, so the following macros `|save_position|' and `|emit_space_if_needed|' are able to handle the situation: @d save_position() save_line=out_line; save_place=out_ptr @d emit_space_if_needed() if (save_line!=out_line || save_place!=out_ptr) out_str("\\Y"); space_checked=true; @.\\Y@> @= static int save_line; /* former value of |out_line| */ static char *save_place; /* former value of |out_ptr| */ static int sec_depth; /* the integer, if any, following \.{@@*} */ static boolean space_checked; /* have we done |emit_space_if_needed|? */ static boolean format_visible; /* should the next format declaration be output? */ static boolean doing_format=false; /* are we outputting a format declaration? */ static boolean group_found=false; /* has a starred section occurred? */ @ @= { section_count++; @@; save_position(); @@; @@; @@; @@; @@; } @ Sections beginning with the \.{CWEB} control sequence `\.{@@\ }' start in the output with the \TEX/ control sequence `\.{\\M}', followed by the section number. Similarly, `\.{@@*}' sections lead to the control sequence `\.{\\N}'. In this case there's an additional parameter, representing one plus the specified depth, immediately after the~\.{\\N}. If the section has changed, we put \.{\\*} just after the section number. @= if (*(loc-1)!='*') out_str("\\M"); @.\\M@> else { while (*loc == ' ') loc++; if (*loc=='*') { /* ``top'' level */ sec_depth = -1; loc++; } else { for (sec_depth=0; xisdigit(*loc);loc++)@^system dependencies@> if (sec_depth < INT_MAX / 10) sec_depth = sec_depth*10 + (*loc) -'0'; } while (*loc == ' ') loc++; /* remove spaces before group title */ group_found=true; out_str("\\N"); @.\\N@> {@+ char s[32];@+snprintf(s,32,"{%d}",sec_depth+1);@+out_str(s);@+} if (show_progress) { printf("*%d",(int)section_count); update_terminal(); /* print a progress report */ } } out('{'); out_section(section_count); out('}'); @ In the \TEX/ part of a section, we simply copy the source text, except that index entries are not copied and \CEE/ text within \pb\ is translated. @= do switch (next_control=copy_TeX()) { case '|': init_stack(); output_C(); break; case '@@': out('@@'); break; case TeX_string: case noop: case xref_roman: case xref_wildcard: case xref_typewriter: case section_name: loc-=2; next_control=get_next(); /* skip to \.{@@>} */ if (next_control==TeX_string) err_print("! TeX string should be in C text only"); break; @.TeX string should be...@> case thin_space: case math_break: case ord: case line_break: case big_line_break: case no_line_break: case join: case pseudo_semi: case macro_arg_open: case macro_arg_close: case output_defs_code: err_print("! You can't do that in TeX text"); break; @.You can't do that...@> } while (next_control=format_code|, and the token memory is in its initial empty state. @= space_checked=false; while (next_control<=definition) { /* |format_code| or |definition| */ init_stack(); if (next_control==definition) @@; else @@; outer_parse(); finish_C(format_visible); format_visible=true; doing_format=false; } @ The |finish_C| procedure outputs the translation of the current scraps, preceded by the control sequence `\.{\\B}' and followed by the control sequence `\.{\\par}'. It also restores the token and scrap memories to their initial empty state. A |force| token is appended to the current scraps before translation takes place, so that the translation will normally end with \.{\\6} or \.{\\7} (the \TEX/ macros for |force| and |big_force|). This \.{\\6} or \.{\\7} is replaced by the concluding \.{\\par} or by \.{\\Y\\par}. @c static void finish_C( /* finishes a definition or a \CEE/ part */ boolean visible) /* |true| if we should produce \TeX\ output */ { text_pointer p; /* translation of the scraps */ if (visible) { out_str("\\B"); app_tok(force); app_scrap(insert,no_math); p=translate(); @.\\B@> app(tok_flag+(int)(p-tok_start)); make_output(); /* output the list */ if (out_ptr>out_buf+1) if (*(out_ptr-1)=='\\') { @.\\6@> @.\\7@> @.\\Y@> if (*out_ptr=='6') out_ptr-=2; else if (*out_ptr=='7') *out_ptr='Y'; } out_str("\\par"); finish_line(); } if (text_ptr>max_text_ptr) max_text_ptr=text_ptr; if (tok_ptr>max_tok_ptr) max_tok_ptr=tok_ptr; if (scrap_ptr>max_scr_ptr) max_scr_ptr=scrap_ptr; tok_ptr=tok_mem+1; text_ptr=tok_start+1; scrap_ptr=scrap_info; /* forget the tokens and the scraps */ } @ @=@+static void finish_C(boolean); @ Keeping in line with the conventions of the \CEE/ preprocessor (and otherwise contrary to the rules of \.{CWEB}) we distinguish here between the case that `\.(' immediately follows an identifier and the case that the two are separated by a space. In the latter case, and if the identifier is not followed by `\.(' at all, the replacement text starts immediately after the identifier. In the former case, it starts after we scan the matching `\.)'. @= { if (save_line!=out_line || save_place!=out_ptr || space_checked) app(backup); if(!space_checked){emit_space_if_needed();save_position();} app_str("\\D"); /* this will produce `\#\&{define }' */ @.\\D@> if ((next_control=get_next())!=identifier) err_print("! Improper macro definition"); @.Improper macro definition@> else { app('$'); app_cur_id(false); if (*loc=='(') { reswitch: switch (next_control=get_next()) { case '(': case ',': app(next_control); goto reswitch; case identifier: app_cur_id(false); goto reswitch; case ')': app(next_control); next_control=get_next(); break; case dot_dot_dot: app_str("\\,\\ldots\\,"); @.\\,@> @.\\ldots@> app_scrap(raw_int,no_math); if ((next_control=get_next())==')') { app(next_control); next_control=get_next(); break; } @=/* otherwise fall through */@>@; default: err_print("! Improper macro definition"); break; } } else next_control=get_next(); app_str("$ "); app(break_space); app_scrap(dead,no_math); /* scrap won't take part in the parsing */ } } @ @= { doing_format=true; if(*(loc-1)=='s' || *(loc-1)=='S') format_visible=false; if(!space_checked){emit_space_if_needed();save_position();} app_str("\\F"); /* this will produce `\&{format }' */ @.\\F@> next_control=get_next(); if (next_control==identifier) { app(id_flag+(int)(id_lookup(id_first, id_loc,normal)-name_dir)); app(break_space); /* this is syntactically separate from what follows */ next_control=get_next(); if (next_control==identifier) { app(id_flag+(int)(id_lookup(id_first, id_loc,normal)-name_dir)); app_scrap(exp,maybe_math); app_scrap(semi,maybe_math); next_control=get_next(); } } if (scrap_ptr!=scrap_info+2) err_print("! Improper format definition"); @.Improper format definition@> } @ Finally, when the \TEX/ and definition parts have been treated, we have |next_control>=begin_C|. We will make the global variable |this_section| point to the current section name, if it has a name. @= static name_pointer this_section; /* the current section name, or zero */ @ @= this_section=name_dir; if (next_control<=section_name) { emit_space_if_needed(); init_stack(); if (next_control==begin_C) next_control=get_next(); else { this_section=cur_section; @@; } while (next_control<=section_name) { outer_parse(); @@; } finish_C(true); } @ The title of the section and an $\E$ or $\mathrel+\E$ are made into a scrap that should not take part in the parsing. @= do next_control=get_next(); while (next_control=='+'); /* allow optional `\.{+=}' */ if (next_control!='=' && next_control!=eq_eq) err_print("! You need an = sign after the section name"); @.You need an = sign...@> else next_control=get_next(); if (out_ptr>out_buf+1 && *out_ptr=='Y' && *(out_ptr-1)=='\\') app(backup); /* the section name will be flush left */ @.\\Y@> app(section_flag+(int)(this_section-name_dir)); cur_xref=(xref_pointer)this_section->xref; if(cur_xref->num==file_flag) cur_xref=cur_xref->xlink; app_str("${}"); if (cur_xref->num!=section_count+def_flag) { app_str("\\mathrel+"); /* section name is multiply defined */ this_section=name_dir; /* so we won't give cross-reference info here */ } app_str("\\E"); /* output an equivalence sign */ @.\\E@> app_str("{}$"); app(force); app_scrap(dead,no_math); /* this forces a line break unless `\.{@@+}' follows */ @ @= if (next_control next_control=get_next(); } else if (next_control==section_name) { app(section_flag+(int)(cur_section-name_dir)); app_scrap(section_scrap,maybe_math); next_control=get_next(); } @ Cross references relating to a named section are given after the section ends. @= if (this_section>name_dir) { cur_xref=(xref_pointer)this_section->xref; if ((an_output=(cur_xref->num==file_flag))==true) cur_xref=cur_xref->xlink; if (cur_xref->num>def_flag) cur_xref=cur_xref->xlink; /* bypass current section number */ footnote(def_flag); footnote(cite_flag); footnote(0); } @ The |footnote| procedure gives cross-reference information about multiply defined section names (if the |flag| parameter is |def_flag|), or about references to a section name (if |flag==cite_flag|), or to its uses (if |flag==0|). It assumes that |cur_xref| points to the first cross-reference entry of interest, and it leaves |cur_xref| pointing to the first element not printed. Typical outputs: `\.{\\A101.}'; `\.{\\Us 370\\ET1009.}'; `\.{\\As 8, 27\\*\\ETs64.}'. Note that the output of \.{CWEAVE} is not English-specific; users may supply new definitions for the macros \.{\\A}, \.{\\As}, etc. @c static void footnote( /* outputs section cross-references */ sixteen_bits flag) { xref_pointer q=cur_xref; /* cross-reference pointer variable */ if (q->num<=flag) return; finish_line(); out('\\'); @.\\A@> @.\\Q@> @.\\U@> out(flag==0? 'U': flag==cite_flag? 'Q': 'A'); @@; out('.'); } @ @=@+static void footnote(sixteen_bits); @ The following code distinguishes three cases, according as the number of cross-references is one, two, or more than two. Variable |q| points to the first cross-reference, and the last link is a zero. @= if (q->xlink->num>flag) out('s'); /* plural */ while (true) { out_section(cur_xref->num-flag); cur_xref=cur_xref->xlink; /* point to the next cross-reference to output */ if (cur_xref->num<=flag) break; if (cur_xref->xlink->num>flag) out_str(", "); /* not the last */ else {out_str("\\ET"); /* the last */ @.\\ET@> if (cur_xref != q->xlink) out('s'); /* the last of more than two */ } } @ @= out_str("\\fi"); finish_line(); @.\\fi@> flush_buffer(out_buf,false,false); /* insert a blank line, it looks nice */ @** Phase three processing. We are nearly finished! \.{CWEAVE}'s only remaining task is to write out the index, after sorting the identifiers and index entries. If the user has set the |no_xref| flag (the \.{-x} option on the command line), just finish off the page, omitting the index, section name list, and table of contents. @c static void phase_three(void) { phase=3; finish_line(); /* the bulk of |tex_file| has been written */ if (no_xref) out_str("\\end"); @.\\end@> else { if (show_progress) printf("%s","\nWriting the index..."); @.Writing the index...@> if (change_exists) { @@; finish_line(); flush_buffer(out_buf,false,false); /* insert a blank line, it looks nice */ } out_str("\\inx"); finish_line(); @.\\inx@> @# if ((idx_file=fopen(idx_file_name,"wb"))==NULL) fatal("! Cannot open index file ",idx_file_name); @.Cannot open index file@> active_file=idx_file; /* change active file to the index file */ @@; @@; finish_line(); fclose(active_file); /* finished with |idx_file| */ @# active_file=tex_file; /* switch back to |tex_file| for a tic */ out_str("\\fin"); finish_line(); @.\\fin@> @# if ((scn_file=fopen(scn_file_name,"wb"))==NULL) fatal("! Cannot open section file ",scn_file_name); @.Cannot open section file@> active_file=scn_file; /* change active file to section listing file */ @@; finish_line(); fclose(active_file); /* finished with |scn_file| */ @# active_file=tex_file; /* switch back to |tex_file| for the last time */ if (group_found) out_str("\\con");@+else out_str("\\end"); @.\\con@> @.\\end@> } finish_line(); fclose(active_file); if (show_happiness) { if (show_progress) new_line(); printf("%s","Done."); } check_complete(); /* was all of the change file used? */ } @ @=@+static void phase_three(void); @ Just before the index comes a list of all the changed sections, including the index section itself. @= /* remember that the index is already marked as changed */ sixteen_bits k_section=0; /* runs through the sections */ while (!changed_section[++k_section]); out_str("\\ch "); @.\\ch@> out_section(k_section); while (k_section= static name_pointer bucket[256]={NULL}; static name_pointer next_name; /* successor of |cur_name| when sorting */ static name_pointer blink[max_names]; /* links in the buckets */ @ To begin the sorting, we go through all the hash lists and put each entry having a nonempty cross-reference list into the proper bucket. @= for (hash_ptr=hash; hash_ptr<=hash_end; hash_ptr++) { next_name=*hash_ptr; while (next_name) { cur_name=next_name; next_name=cur_name->link; if (cur_name->xref!=(void *)xmem) { int c=(cur_name->byte_start)[0]; if (xisupper(c)) c=tolower(c); blink[cur_name-name_dir]=bucket[c]; bucket[c]=cur_name; } } } @ During the sorting phase we shall use the |cat| and |trans| arrays from \.{CWEAVE}'s parsing algorithm and rename them |depth| and |head|. They now represent a stack of identifier lists for all the index entries that have not yet been output. The variable |sort_ptr| tells how many such lists are present; the lists are output in reverse order (first |sort_ptr|, then |sort_ptr-1|, etc.). The |j|th list starts at |head[j]|, and if the first |k| characters of all entries on this list are known to be equal we have |depth[j]==k|. @= name_pointer Head; @ @d depth cat /* reclaims memory that is no longer needed for parsing */ @d head trans_plus.Head /* ditto */ @f sort_pointer int @d sort_pointer scrap_pointer /* ditto */ @d sort_ptr scrap_ptr /* ditto */ @= static eight_bits cur_depth; /* depth of current buckets */ static char *cur_byte; /* index into |byte_mem| */ static sixteen_bits cur_val; /* current cross-reference number */ static sort_pointer max_sort_ptr; /* largest value of |sort_ptr| */ @ @= max_sort_ptr=scrap_info; @ The desired alphabetic order is specified by the |collate| array; namely, $|collate|[0]<|collate|[1]<\cdots<|collate|[100]$. @= static eight_bits collate[101+128]; /* collation order */ @^high-bit character handling@> @ We use the order $\hbox{null}<\.\ <\hbox{other characters}<{}$\.\_${}< \.A=\.a<\cdots<\.Z=\.z<\.0<\cdots<\.9.$ Warning: The collation mapping needs to be changed if ASCII code is not being used. @^ASCII code dependencies@> @^high-bit character handling@> We initialize |collate| by copying a few characters at a time, because some \CEE/ compilers choke on long strings.@^system dependencies@> @= collate[0]=0; memcpy((char *)collate+1, " \1\2\3\4\5\6\7\10\11\12\13\14\15\16\17",16); /* 16 characters + 1 = 17 */ memcpy((char *)collate+17, "\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37",16); /* 16 characters + 17 = 33 */ memcpy((char *)collate+33, "!\42#$%&'()*+,-./:;<=>?@@[\\]^`{|}~_",32); /* 32 characters + 33 = 65 */ memcpy((char *)collate+65, "abcdefghijklmnopqrstuvwxyz0123456789",36); /* (26 + 10) characters + 65 = 101 */ memcpy((char *)collate+101, "\200\201\202\203\204\205\206\207\210\211\212\213\214\215\216\217",16); /* 16 characters + 101 = 117 */ memcpy((char *)collate+117, "\220\221\222\223\224\225\226\227\230\231\232\233\234\235\236\237",16); /* 16 characters + 117 = 133 */ memcpy((char *)collate+133, "\240\241\242\243\244\245\246\247\250\251\252\253\254\255\256\257",16); /* 16 characters + 133 = 149 */ memcpy((char *)collate+149, "\260\261\262\263\264\265\266\267\270\271\272\273\274\275\276\277",16); /* 16 characters + 149 = 165 */ memcpy((char *)collate+165, "\300\301\302\303\304\305\306\307\310\311\312\313\314\315\316\317",16); /* 16 characters + 165 = 181 */ memcpy((char *)collate+181, "\320\321\322\323\324\325\326\327\330\331\332\333\334\335\336\337",16); /* 16 characters + 181 = 197 */ memcpy((char *)collate+197, "\340\341\342\343\344\345\346\347\350\351\352\353\354\355\356\357",16); /* 16 characters + 197 = 213 */ memcpy((char *)collate+213, "\360\361\362\363\364\365\366\367\370\371\372\373\374\375\376\377",16); /* 16 characters + 213 = 229 */ @ Procedure |unbucket| goes through the buckets and adds nonempty lists to the stack, using the collating sequence specified in the |collate| array. The parameter to |unbucket| tells the current depth in the buckets. Any two sequences that agree in their first 255 character positions are regarded as identical. @d infinity 255 /* $\infty$ (approximately) */ @c static void unbucket( /* empties buckets having depth |d| */ eight_bits d) { int c; /* index into |bucket|; cannot be a simple |char| because of sign comparison below */ for (c=100+128; c>= 0; c--) if (bucket[collate[c]]) { @^high-bit character handling@> if (sort_ptr>=scrap_info_end) overflow("sorting"); sort_ptr++; if (sort_ptr>max_sort_ptr) max_sort_ptr=sort_ptr; if (c==0) sort_ptr->depth=infinity; else sort_ptr->depth=d; sort_ptr->head=bucket[collate[c]]; bucket[collate[c]]=NULL; } } @ @=@+static void unbucket(eight_bits); @ @= sort_ptr=scrap_info; unbucket(1); while (sort_ptr>scrap_info) { cur_depth=sort_ptr->depth; if (blink[sort_ptr->head-name_dir]==0 || cur_depth==infinity) @@; else @@; } @ @= { int c; next_name=sort_ptr->head; do { cur_name=next_name; next_name=blink[cur_name-name_dir]; cur_byte=cur_name->byte_start+cur_depth; if (cur_byte==(cur_name+1)->byte_start) c=0; /* hit end of the name */ else if (xisupper(c=*cur_byte)) c=tolower(c); blink[cur_name-name_dir]=bucket[c]; bucket[c]=cur_name; } while (next_name); --sort_ptr; unbucket(cur_depth+1); } @ @= { cur_name=sort_ptr->head; do { out_str("\\I"); @.\\I@> @@; @@; cur_name=blink[cur_name-name_dir]; } while (cur_name); --sort_ptr; } @ @= switch (cur_name->ilk) {@+char *p; /* index into |byte_mem| */@+@t}\6{\4@> case normal: case func_template: if (is_tiny(cur_name)) out_str("\\|"); else {@+boolean all_caps=true;@+@t}\6{@> for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++) if (xislower(*p)) { /* not entirely uppercase */ all_caps=false; break; } out_str(all_caps ? "\\." : "\\\\"); } break; @.\\|@> @.\\.@> @.\\\\@> case wildcard: out_str("\\9");@+ goto not_an_identifier; @.\\9@> case typewriter: out_str("\\.");@+ goto not_an_identifier; @.\\.@> case roman: not_an_identifier: out_name(cur_name,false); goto name_done; case custom: out_str("$\\"); for (p=cur_name->byte_start;p<(cur_name+1)->byte_start;p++) out(*p=='_'? 'x': *p=='$'? 'X': *p); out('$'); goto name_done; default: out_str("\\&"); @.\\\&@> } out_name(cur_name,true); name_done:@; @ Section numbers that are to be underlined are enclosed in `\.{\\[}$\,\ldots\,$\.]'. @= @@; do { out_str(", "); cur_val=cur_xref->num; if (cur_val cur_xref=cur_xref->xlink; } while (cur_xref!=xmem); out('.'); finish_line(); @ List inversion is best thought of as popping elements off one stack and pushing them onto another. In this case |cur_xref| will be the head of the stack that we push things onto. @= static xref_pointer next_xref, this_xref; /* pointer variables for rearranging a list */ @ @= this_xref=(xref_pointer)cur_name->xref; cur_xref=xmem; do { next_xref=this_xref->xlink; this_xref->xlink=cur_xref; cur_xref=this_xref; this_xref=next_xref; } while (this_xref!=xmem); @ The following recursive procedure walks through the tree of section names and prints them. @^recursion@> @c static void section_print( /* print all section names in subtree |p| */ name_pointer p) { if (p) { section_print(p->llink); out_str("\\I"); @.\\I@> tok_ptr=tok_mem+1; text_ptr=tok_start+1; scrap_ptr=scrap_info; init_stack(); app(section_flag+(int)(p-name_dir)); make_output(); footnote(cite_flag); footnote(0); /* |cur_xref| was set by |make_output| */ finish_line();@/ section_print(p->rlink); } } @ @=@+static void section_print(name_pointer); @ @=section_print(root); @ Because on some systems the difference between two pointers is a |ptrdiff_t| rather than an |int|, we use \.{\%td} to print these quantities. @c void print_stats(void) { puts("\nMemory usage statistics:"); @.Memory usage statistics:@> printf("%td names (out of %ld)\n",@^system dependencies@> (ptrdiff_t)(name_ptr-name_dir),(long)max_names); printf("%td cross-references (out of %ld)\n", (ptrdiff_t)(xref_ptr-xmem),(long)max_refs); printf("%td bytes (out of %ld)\n", (ptrdiff_t)(byte_ptr-byte_mem),(long)max_bytes); puts("Parsing:"); printf("%td scraps (out of %ld)\n", (ptrdiff_t)(max_scr_ptr-scrap_info),(long)max_scraps); printf("%td texts (out of %ld)\n", (ptrdiff_t)(max_text_ptr-tok_start),(long)max_texts); printf("%td tokens (out of %ld)\n", (ptrdiff_t)(max_tok_ptr-tok_mem),(long)max_toks); printf("%td levels (out of %ld)\n", (ptrdiff_t)(max_stack_ptr-stack),(long)stack_size); puts("Sorting:"); printf("%td levels (out of %ld)\n", (ptrdiff_t)(max_sort_ptr-scrap_info),(long)max_scraps); } @** Index. If you have read and understood the code for Phase III above, you know what is in this index and how it got here. All sections in which an identifier is used are listed with that identifier, except that reserved words are indexed only when they appear in format definitions, and the appearances of identifiers in section names are not indexed. Underlined entries correspond to where the identifier was declared. Error messages, control sequences put into the output, and a few other things like ``recursion'' are indexed here too.