\ProvidesPackage{dlfltxbcodetips}[2010/03/04 v0.5 by Lars 'daleif' Madsen]

% this pacakge collects some macros presented as code tips in my LaTeX
% book: "Introduktion til LaTeX". As the macros might be useful for
% other than the normal readers of my book, the longer macros are
% collected in this package.

% This package be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%   http://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2003/12/01 or later.
%% 
%% This work has the LPPL maintenance status "maintained".
%% 
%% The Current Maintainer of this work is Lars Madsen (daleif@imf.au.dk).
%%


% HISTORY
%
% 20070601 Added better implementation of \nuparrow, \ndownarrow and
%          \bigtimes, all due to Enrico Gregorio
%          also made the environment uded inside \NewShadedTheorem
%          configurable. 
% 20070604 Karl Ove Hufthammer mentioned that mathdesign does not like
%          amssymb, and _does_ implement \nleftarrow \nrightnarrow. The
%          package option 'noamssymb' now disables loading amssymb
% 20070606 alternative konstruction of \NewShadedTheorem, now using
%          ntheorem konstructions internally
% 20070710 bug fix regarding shadedtheorems, the counter aliasing did
%          not work correctly
% 20070711 Bug fixed in \ArrowBetweenLines, the \ifin@ should go
%          inside the \noalign, not outside.
% 20080617 added \DeclareMathSymbolShorthand and \DeclareMathSet
% 20080618 redesigned and renamed \PullBack to \MoveEqLeft
% 20080828 added better implementation of \MakeDeclareMathSetCommand
% 20100304 updated for latest release

\newif\ifdlf@do@load@amssymb
\dlf@do@load@amssymbtrue

\DeclareOption{noamssymb}{\dlf@do@load@amssymbfalse}

\ProcessOptions\relax

\RequirePackage{amsmath}



% \InsertTheoremBreak removes the spacing above the first item,
% \InsertTheoremBreak* does not
\newcommand\InsertTheoremBreak{%
    \@ifstar{\item[\vbox{\null}]}{%
      \begingroup % keep changes local
      \setlength\itemsep{0pt}%
      \setlength\parsep{0pt}%
       \item[\vbox{\null}]%
      \endgroup%
     }}



% for making theorems with shaded background
% requires the use of ntheorem, (x)color and framed
% currently only ntheorem is supported (perhaps support for amsthm or
% theorem will be added later)
% has the same syntax as \newtheorem
%
% redesigned 2007/06/06
\def\theoremframecommand{}
\newcommand\NewShadedTheorem[1]{%
  \@ifnextchar[{\NST@levelii{#1}}{\NST@levelii{#1}[]}}
\def\NST@levelii#1[#2]#3{%
  \@ifnextchar[{\NST@leveliii{#1}[#2]{#3}}{\NST@leveliii{#1}[#2]{#3}[]}}
\newcommand\NST@helper[1]{%
  \edef\@tempa{c@#1}\edef\@tempb{c@#1@inner}%
  \expandafter\let\csname\@tempa\expandafter\endcsname\csname\@tempb\endcsname%
  \edef\@tempa{p@#1}\edef\@tempb{p@#1@inner}%
  \expandafter\let\csname\@tempa\expandafter\endcsname\csname\@tempb\endcsname%
  \edef\@tempa{cl@#1}\edef\@tempb{cl@#1@inner}%
  \expandafter\let\csname\@tempa\expandafter\endcsname\csname\@tempb\endcsname%
  \edef\@tempa{the#1}\edef\@tempb{the#1@inner}%
  \expandafter\let\csname\@tempa\expandafter\endcsname\csname\@tempb\endcsname%
}
\def\NST@leveliii#1[#2]#3[#4]{%
  \ifx\\#2\\% i.e. no common counter
    \ifx\\#4\\% i.e. no dominant counter
      \newshadedtheorem{#1@inner}{#3}%
      \NST@helper{#1}%
    \else% i.e. dominant counter
      \newshadedtheorem{#1@inner}{#3}[#4]%
      \NST@helper{#1}%
  \fi%
  \else% i.e. common counter
    \newshadedtheorem{#1@inner}[#2]{#3}%
  \fi%
  \newenvironment{#1}{%
    % code stolen from ntheorem.sty
    \thm@topsepadd \theorempostskipamount
    \ifvmode \advance\thm@topsepadd\partopsep\fi
    \trivlist
    \@topsep \theorempreskipamount
    \@topsepadd \thm@topsepadd
    \item
      \setlength\theorempreskipamount{0pt}%
      \setlength\theorempostskipamount{0pt}%
      \begin{#1@inner}
      }{\end{#1@inner}\endtrivlist\@endparenv}%
  }




% this implements a stack that holds a user build mathindent
% not easy to explain in words see the documentation
\newtoks\dlf@STACK
\def\dlf@Prepend#1(to:)#2{\toks0={#1}%
  \global\edef\act{\global\noexpand#2={\the\toks0 \the#2}}%
  \act}
\def\dlf@PopOff#1{\global\edef\act{\global\noexpand\dlf@SplitOff\the#1%
    (tail:)\noexpand#1}\act}
\def\dlf@SplitOff#1#2(tail:)#3{#3={#2}} 
\newlength\MathIndentLength
\newcommand\MathIndent{\kern\MathIndentLength}
\newcommand\PopMathIndent{%
  \@ifstar{\@PopMathIndent\relax}{\@PopMathIndent\MathIndent}}
\newcommand\@PopMathIndent[1]{\dlf@PopOff\dlf@STACK
  \settowidth\@tempdimc{\ensuremath{\displaystyle\phantom{\the\dlf@STACK}}}
  \setlength{\global\MathIndentLength}{\@tempdimc}#1}
\newcommand\SetMathIndent[1]{\dlf@STACK={}\dlf@Prepend{{#1}}(to:)\dlf@STACK
  \settowidth\@tempdimc{\ensuremath{\displaystyle\phantom{\the\dlf@STACK}}}
  \setlength{\global\MathIndentLength}{\@tempdimc}#1}
\newcommand\AddtoMathIndent[1]{\dlf@Prepend{{#1}}(to:)\dlf@STACK
  \settowidth\@tempdimc{\ensuremath{\displaystyle\phantom{\the\dlf@STACK}}}
   \setlength{\global\MathIndentLength}{\@tempdimc}#1}


% this constructs a version of \bigtimes. The version here is due to
% Enrico Gregorio, presented in http://groups.google.com/group/comp.text.tex/msg/9685c9405df2ff94

\newcommand\dlf@b@gtimes[1]{%
  \vcenter{\hbox{#1$\m@th\mkern-2mu\times\mkern-2mu$}}}
\newcommand\dlf@bigtimes{%
  \mathchoice{\dlf@b@gtimes\huge}         % display style
             {\dlf@b@gtimes\LARGE}        % text style
             {\dlf@b@gtimes{}}            % script style
             {\dlf@b@gtimes\footnotesize} % script script style
}
\newcommand\bigtimes{\mathop{\dlf@bigtimes}\displaylimits}



\ifdlf@do@load@amssymb
  \RequirePackage{amssymb}
\fi

\RequirePackage{graphicx}

% better construction for \nuparrow and \ndownarrow, se also
% http://groups.google.com/group/comp.text.tex/msg/689cc8bd604fdb51 
% again due to Enrico Gregorio
% construction requires graphicx
\def\dlf@nrotarrow#1#2{%
  \setbox0=\hbox{$\m@th#1\uparrow$}\dimen0=\dp0
  \setbox0=\hbox{%
    \reflectbox{\rotatebox[origin=c]{90}{$\m@th#1\mkern2.22mu #2$}}}%
  \dp0=\dimen0 \box0 \mkern2.3965mu
}

% needs to delay things
\AtBeginDocument{
  \@ifundefined{nrightarrow}{%
    \PackageWarning{dlfltxbcodetips}{\string\nrightarrow\space not found,^^J 
      \string\nuparrow\space will not be defined}
  }{
    \def\nuparrow{\mathrel{\mathpalette\dlf@nrotarrow\nrightarrow}}
  }
  
  \@ifundefined{nleftarrow}{%
    \PackageWarning{dlfltxbcodetips}{\string\nleftarrow\space not found,^^J 
      \string\ndownarrow\space will not be defined}
  }{
    \def\ndownarrow{\mathrel{\mathpalette\dlf@nrotarrow\nleftarrow}} 
  }
}



\newcommand\ProvidePGFPagesFourOnOneWithSpaceForNotes{%
  \@ifpackageloaded{pgfpages}{%
    \pgfpagesdeclarelayout{4 on 1 with space for notes}
    { \edef\pgfpageoptionheight{\the\paperwidth} % landscaped by default
      \edef\pgfpageoptionwidth{\the\paperheight}
      \def\pgfpageoptionborder{0pt}}
    {  \pgfpagesphysicalpageoptions{logical pages=4,%
        physical height=\pgfpageoptionheight,%
        physical width=\pgfpageoptionwidth}
      \ifdim\paperheight>\paperwidth\relax
      % put side-by-side
      \pgfpageslogicalpageoptions{1}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.25\pgfphysicalwidth,%
        resized height=.5\pgfphysicalheight,%
        center=\pgfpoint{.125\pgfphysicalwidth}{.75\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{2}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.25\pgfphysicalwidth,%
        resized height=.5\pgfphysicalheight,%
        center=\pgfpoint{.625\pgfphysicalwidth}{.75\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{3}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.25\pgfphysicalwidth,%
        resized height=.5\pgfphysicalheight,%
        center=\pgfpoint{.125\pgfphysicalwidth}{.25\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{4}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.25\pgfphysicalwidth,%
        resized height=.5\pgfphysicalheight,%
        center=\pgfpoint{.625\pgfphysicalwidth}{.25\pgfphysicalheight}}%
      \else % stack on top of one another
      \pgfpageslogicalpageoptions{1}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.5\pgfphysicalwidth,%
        resized height=.25\pgfphysicalheight,%
        center=\pgfpoint{.25\pgfphysicalwidth}{.875\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{2}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.5\pgfphysicalwidth,%
        resized height=.25\pgfphysicalheight,%
        center=\pgfpoint{.25\pgfphysicalwidth}{.625\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{3}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.5\pgfphysicalwidth,%
        resized height=.25\pgfphysicalheight,%
        center=\pgfpoint{.25\pgfphysicalwidth}{.375\pgfphysicalheight}}%
      \pgfpageslogicalpageoptions{4}{%
        border shrink=\pgfpageoptionborder,%
        resized width=.5\pgfphysicalwidth,%
        resized height=.25\pgfphysicalheight,%
        center=\pgfpoint{.25\pgfphysicalwidth}{.125\pgfphysicalheight}}%
      \fi    
    }
  }{%
    \PackageError{dlfltxbcodetips}{\string\ProvidePGFPagesFourOnOneWithSpaceForNotes^^J
      can only be used after the pgfpages package have been loaded}{}
}}



\begingroup
\catcode`\_=\active
\gdef\OverloadUnderscoreInMath{%
  \protected\gdef_{\@ifnextchar|\subtextup\sb}
  \gdef\subtextup|##1|{\sb{\textup{##1}}}
  \AtBeginDocument{\catcode`\_=12 \mathcode`\_=32768 }
}
\endgroup
\@onlypreamble\OverloadUnderscoreInMath


\@ifundefined{DeclareMathSymbolShorthand}{
  \usepackage{keyval}
\newcommand*\DeclareMathSymbolShorthand[2]{% #1=keyvals, #2=arg.
   \begingroup
   \setkeys{DMSS}{name=#2,#1}%
   \if\DMSS@overwrite % check for overwrite?
   \else
     \expandafter\@ifdefinable\csname \DMSS@prefix\DMSS@name\endcsname{%
       \def\DMSS@overwrite{00}% okay to redefine.
     }%
   \fi%
   \if\DMSS@overwrite % Do definition or not.
     \expandafter\@firstofone%
   \else\expandafter\@gobble\fi%
   {\protected\expandafter%
     \xdef\csname \DMSS@prefix\DMSS@name \endcsname{%
       \unexpanded\expandafter{\DMSS@format{#2}}}}%
   \endgroup}
\define@key{DMSS}{format}{\let\DMSS@format#1}
\define@key{DMSS}{format*}{\def\DMSS@format{\expandafter#1\@firstofone}}
\define@key{DMSS}{name}{\def\DMSS@name{#1}}
\define@key{DMSS}{prefix}{\def\DMSS@prefix{#1}}
\define@key{DMSS}{overwrite}[true]{%
   \edef\DMSS@overwrite{\csname if#1\endcsname 00\else 01\fi}}
\setkeys{DMSS}{overwrite=false}
\setkeys{DMSS}{format*=}
\newcommand\MakeDeclareMathSetCommand[3]{%
  % #1 = command name 
  % #2 = default prefix name
  % #3 = default format
  % make format macro for eacy reference
   \expandafter\MakeDeclareShorthandCommandAux\csname math#2format\endcsname
   {#1}{#2}{#3}}
\def\MakeDeclareShorthandCommandAux#1#2#3#4{%
   \newcommand*#1{#4}%
   \newcommand*#2[2][]{%
     \DeclareMathSymbolShorthand{format=#1,prefix=#3,##1}{##2}%
   }}
\MakeDeclareMathSetCommand{\DeclareMathSet}{numbers}{\mathbb}
}{} % is defined already so do nothing