%% Macro package `fifinddo.sty' for LaTeX2e,    %% FIDO, FIND!
%% copyright (C) 2009 Uwe L\"uck, 
%%   http://www.contact-ednotes.sty.de.vu 
%% -- author-maintained in the sense of LPPL below -- 
%% for processing tex(t) files 
%% (checking, filtering, converting, substituting, expanding, ...)
 
\def\fileversion{0.3} \def\filedate{2009/04/15}

%% This file can be redistributed and/or modified under 
%% the terms of the LaTeX Project Public License; either 
%% version 1.3a of the License, or any later version.
%% The latest version of this license is in
%%
%%     http://www.latex-project.org/lppl.txt
%%
%% We did our best to help you, but there is NO WARRANTY. 
%% Please report bugs, problems, and suggestions via 
%% 
%%   http://www.contact-ednotes.sty.de.vu 
%% 
%% For the full documentation, look for `fifinddo.pdf'. 
%% Its source starts in `fifinddo.tex'.
%%
%% === Format and package version ===
\NeedsTeXFormat{LaTeX2e}[1994/12/01] 
% 1994/12/01: \newcommand* etc. 
\ProvidesPackage{fifinddo}[\filedate\space v\fileversion\space
                           filtering TeX(t) files by TeX (UL)] 
%% 
%% === Category codes ===
%%
%% We use the ``underscore'' as ``compound identifier.'' 
\catcode`\_=11 %% underscore used in control words
%%
%% |\MakeOther| is a synonym for `\@makeother', needed for matching 
%% special characters from the input file. It is exemplified by 
%% |\fdPatternCodes| which is the default of |\PatternCodes|. 
%% The latter is used in setup macros for reading patterns. 
\@ifundefined{MakeOther}{\let\MakeOther\@makeother}{}
\newcommand*{\fdPatternCodes}{\MakeOther\&\MakeOther\$} 
\newcommand*{\PatternCodes}{} \let\PatternCodes\fdPatternCodes 
  %% TODO adding/removing 
%% It would be bad to have `\MakeOther\%' and `\MakeOther\ ' here in 
%% that this may have unexpected, weird effects with arguments of 
%% setup macros. Therefore neither `\dospecials' nor `\@sanitize' are 
%% used. Curly braces remain untouched as default delimiters in setup 
%% macros. For matching them, you must use `\MakeOther\{' and 
%% `\MakeOther' in your `\PatternCodes', or |\Delimiters| to introduce 
%% new ones at the same time, e.g., `\Delimiters\[\]': 
\newcommand*{\Delimiters}[2]{%
  \MakeOther\{\MakeOther\}\catcode`#1=1\catcode`#2=2\relax}
%% For replacing strings or for defining other strings of ``other'' 
%% characters by `\edef', you can use some \LaTeX\ constructs---here 
%% are copies |\PercentChar| and |\BackslashChar| of them
%% (do you need more?): 
\newcommand*{\PercentChar}{}   \let\PercentChar\@percentchar
\newcommand*{\BackslashChar}{} \let\BackslashChar\@backslashcar
%%
%%  == File handling ==
\newwrite\result_file %% or write to \@mainaux!?
%% |\ResultFile{<output>}| opens (and empties) a file 
%% <output> to be written into. 
\newcommand*{\ResultFile}[1]{%
  \def\result_file_name{#1}%
  \immediate\openout\result_file=#1}
%% |\WriteResult{<balanced>}| writes a <balanced> line into 
%% <output> (or more lines with `^^J').
\newcommand*{\WriteResult}[1]{% 
  \immediate\write\result_file{#1}}
%% |\WriteProvides| writes a `\ProvidesFile' command to the 
%% opened <output> file. This should be used when <output> 
%% is made as \LaTeXe\ input. 
\newcommand*{\WriteProvides}{%
  \WriteResult{%
    \string\ProvidesFile{\result_file_name}% 
      [\the\year/\two@digits\month/\two@digits\day\space 
       automatically generated with fifinddo.sty]}}%
%% |\ProcessFileWith{<input>}{<loop-body>}| opens a file <input> 
%% and runs a loop on its lines the main body of which is <loop-body>. 
%% When it starts, a new line of <input> is stored as macro 
%% |\fdInputLine|. 
\newcommand*{\ProcessFileWith}[2]{%
  \openin\@inputcheck=#1%
%   \ifeof\@inputcheck  %% bad `exists?' test
%     \PackageError{fifinddo}{File `#1' not here}%
%                            {Mistyped?}%
%   \else
    \global\c@fdInputLine=\z@ %% line counter reset
    \begingroup 
      \MakeOther\{\MakeOther\}\@sanitize
      %% from docstrip.tex: 
      % \MakeOther\^^A\MakeOther\^^K%% irrelevant, not LaTeX
      \endlinechar\m@ne
      %% <- cf. TeXbook "extended keyboards" up-/downarrow
      %%    -> "math specials", cf. "space specials"
      \MakeOther\^^I% ASCII horizontal tab -- guessed!? ^^L!?
      \loop \ifeof\@inputcheck \else 
        \read\@inputcheck to \fdInputLine
        \ignorespaces #2%
      \repeat
    \endgroup
%   \fi
  \closein\@inputcheck} 
%% |\CloseResultFile| closes <output>. 
\newcommand*{\CloseResultFile}{\immediate\closeout\result_file}
%% Peter Wilson's 'newfile' provides more powerful file handling. 
%% % <- TODO relevant? 2009/04/12
%%
%% \pagebreak %% TODO move theory to fifinddo.tex 2009/04/12
%%  == Basic handling of substring conditionals ==
%% \label{sec:theory}
%% === ``Substring Theory'' === 
%% \begin{flushright}\it
%% I wished I could study string theory,\\
%% but I only could study substring theory.
%% \end{flushright}
%% A \TeX\ macro, say, `\find' whose parameter text 
%% (cf. \TeX book p.~203)
%% starts with `#1<pattern>#2&' stops \TeX\ with an error if it does 
%% not find <pattern> and then `&'. Otherwise we have a situation 
%% `\find<split1><pattern><split2>&', and `\find' reads <split1> as 
%% #1 and <split2> as #2. An important point to note is that <split1> 
%% will not contain <pattern>, but possibly <pattern> has more 
%% occurrences in <split2>. In this sense, `\find' uses the 
%% \emph{first} occurrence of <pattern> it finds in order to delimit #1. 
%% Finding the \emph{last} occurrence of <pattern> therefore needs a 
%% special idea. 
%%
%% In order to use `\find' for a test whether <pattern> is in 
%% <target>, we build a ``sandbox'' |\find<sand>&|, where <sand> 
%% contains <target> \emph{and additionally} <pattern>---as a 
%% ``dummy;'' so `&' delimits the search and `\find' finds 
%% <pattern> either in <target> or somewhere else before `&'. 
%%
%% Consider the simple sandbox |\find<target><pattern>&|. 
%% We can test #1 and #2 on being empty by `\ifx$#1$' and `\ifx$#2$'. 
%% If #2 is empty, <pattern> is \emph{not} in <target>. 
%% If #1 is empty at the same time, <target> is empty. 
%% If #1 is empty and #2 is not, <pattern> \emph{starts} <target>! 
%% This can be used to implement 
%% Wikipedia-like lists                 %% TODO 2009/04/11
%% and to distinguish package code from comments in 'makedoc'. 
%%
%% If #2 is \emph{not} empty, <pattern> occurs in <target>---or this once 
%% was \emph{thought}, some time in developping the present package, 
%% as well as in the version of 'substr.sty' marked 
%% `2005-11-29',\footnote{\hspace{1sp}'substr' does not change 
%%   category codes 
%%   % as 'fifinddo' does 
%%   and uses \cs{@nil} as delimiter instead of our &&.} try 
%% \[`\IfSubStringInString{<str1><str2><str1>}{<str1><str2>}{YES}{NO}'\] 
%% which works \emph{verbatim} as well as considering <str1> and 
%% <str2> \emph{placeholders}, e.g., for
%% \begin{center}
%%   `\IfSubStringInString{day after day}{day after }{YES}{NO}'\footnote{%
%%     Likewise \texttt{t\string\^ete-\string\`a-t\string\^te} ...}\\
%%   `\IfSubStringInString{AMSTERDAM}{AMSTERD}{YES}{NO}'\\
%%   `\IfSubStringInString{TORONTO}{TORON}{YES}{NO}'\\
%%   `\IfSubStringInString{bonbon}{bon}{YES}{NO}'\footnote{%
%%     Polynesian: `aku aku', `rongorongo', `wiki wiki' ...}\\
%%   `\IfSubStringInString{bonobo}{bono}{YES}{NO}'
%%   (an ape)
%% \end{center}
%% or `\IfSubStringInString{ionization}{ionizat}{YES}{NO}'.\footnote{%
%%   Read 'substr.sty' or try ``normal'' things to convince yourself 
%%   that the syntax indeed is 
%%   &\IfSubStringInString{<pattern>}{<target>}{<yes>}{<no>}.} 
%% Same with \LaTeX's internal `\in@':
%% \[`\makeatletter \in@{bonbon}{bon}\ifin@ YES\else NO\fi \makeatother'\]
%% %% \makeatletter \in@{bonbon}{bon}\ifin@ YES\else NO\fi \makeatother
%% %% \IfSubStringInString{ionization}{ionizat}{YES}{NO}
%%
%% In general, the previous approach \emph{fails if and exactly if} 
%% <pattern> has a \emph{period} $p$---less than its length---in the sense of that 
%% the $p$th token to the right or left of each token in <pattern> 
%% is the \emph{same} token. 
%% `AMSTERDAM' has a period 8, `day after day' 10, `bonbon' 3, `bonobo' 4.
%% There is a counterexample <target> of length $p$ iff 
%% <pattern> has period $p$, namely the first substring of <pattern> 
%% having length $p$. If the length of <pattern> exceeds a multiple 
%% $mp$ of its period, the first $mp$ tokens of <pattern> form 
%% a counterexample <target>. 
%%
%% Therefore, a sandbox must have something between <target> and 
%% <pattern>. We choose |\find<target>~<pattern>$&| as standard. 
%% The `$' will be used as an argument delimiter to get rid of the dummy 
%% <pattern> in <split2>, as well as to decide whether the match was 
%% in <target> or in the dummy part of the sandbox. 
%% The `$' can be replaced by another tilde `~' in order to 
%% test whether <target> \emph{ends} on a <pattern>, defining a macro 
%% like `\findatend' whose parameter text starts with `#1<pattern>~#2&'.
%% 
%% === Plan for proceeding ===
%% When we check a file for several patterns, we seem to need 
%% \emph{two} macros for each pattern: one that has the pattern 
%% in its parameter text and one that stores the pattern for building 
%% the sandbox.\footnote{If it were for the pattern only, the parsing 
%%   macro might suffice and the macro calling it might extract the 
%%   pattern from a ``dummy expansion.'' Somewhat too much for me now; 
%%   on the other hand the calling macro also hands some ``current'' 
%%   informations to the parsing macro---oh, even this could be 
%%   handled by a general ``calling'' macro \dots}
%%   %% TODO 2009/04/15
%% We use a separate \emph{``name space''} for each of 
%% both kinds. The parsing macro and the macro building the sandbox 
%% will have a common \emph{``identifier''} by which the user or 
%% programmer calls them. Actually, she will usually (first) call 
%% the sandbox box builder. The sandbox builder calls the parsing 
%% macro. When \emph{all} occurrences of a pattern in the target are 
%% looked for, the parser may call itself. 
%%
%% Actually, the parsing macro will execute certain actions 
%% depending on what it finds in the sandbox, so we call it a 
%% \emph{``substring conditional''}. It may read additional arguments 
%% after the sandbox that store information gathered before. 
%% This is especially useful for designing \emph{``expandable''} 
%% chains (sequences) of conditionals where macros cannot store information in 
%% macros. The macro setting up the sandbox will initialize such 
%% extra arguments at the same time. 
%%
%% It may be more efficient \emph{not} to use the following setup 
%% macros but to type the macros yourself, just using the following 
%% as templates. The setup macros are especially useful with patterns 
%% that contain ``special characters,'' as when you are looking for 
%% lines that might be package comments. 
%%
%% === Set up conditionals ===
%% `substr_cond' is the ``name space'' for substring conditionals. 
%% A colon separates it from \emph{``job identifiers''} in the actual 
%% macro names. 
\def\substr_cond{substr_cond:}
%% |\MakeSubstringConditional{<id>}[<changes>]{<pattern>}| 
%% starts the definition of a conditional with \emph{identifier} <id> 
%% and pattern <pattern>. <changes> optionally add commands to 
%% be executed after `\PatternCodes' in a local group. 
%% It may be more safe to redefine `\PatternCodes' instead. 
\newcommand*{\MakeSubstringConditional}{%
  \afterassignment\mk_substr_cond_san \def\cond_id}
\newcommand*{\mk_substr_cond_san}[1][]{%
  \begingroup \PatternCodes #1\mk_substr_cond}
  %% #1 more changes
%% `\begingroup' |\mk_substr_cond{<pattern>}| 
%% can be directly called by other programmer setup commands when 
%% `\cond_id' and <pattern> have been read.
\def\mk_substr_cond #1{%% #1 pattern string
  \endgroup \@namedef{\substr_cond \cond_id}##1#1##2&}
%% This really is not \LaTeX. We are starting defining a macro 
%% `\substr_cond:<id>' in primitive \TeX\ with `\def' in the form
%% \[`\def\substr_cond:<id>#1<pattern>#2&'\]
%% where `\csname' etc. render \lq`:<id>'\rq\ part of the macro name. 
%% The user or programmer macro produces the part of the definition 
%% until the delimiter `&' to match the sandbox. You have to add 
%% (maybe) #3 etc. and the `{<definition text>}' 
%% just as with primitive \TeX.
%%
%% === Set up sandboxes === 
%% There was a \emph{question:} will we rather see 
%% \emph{string macros} or \emph{strings from macro arguments}? 
%% The input file content always comes 
%% as `\fdInputLine' first, so we at least \emph{must account} for 
%% the possibility of string macros as input.
%%
%% One easy way to apply several checks and substitutions to 
%% `\fdInputLine' before the result is written to <output> is 
%% `\let\OutputString\fdInputLine' and then let `\OutputString' 
%% be to what each job refers as \emph{its} 
%% input and output, finally `\WriteResult{\OutputString}'. 
%% (`\fdInputLine' might better not be touched, it could be used 
%% for a final test whether any change applied for some message on 
%% screen, even with an entirely expandable chain of actions.)
%% This way each job, indeed each recursive substitution of a single 
%% string must start with expanding `\OutputString'. 
%%
%% On the other hand, there is the idea of \emph{``expandable'' 
%% chains of substitutions}. We may, e.g., define a macro, say, 
%% `\manysubstitutions{<macro-name>}', such that 
%% `\WriteResult{\manysubstitutions{\fdInputLine}}'
%% writes to <output> the result of applying many expandable 
%% substitutions to `\fdInputLine'. 
%% Such a macro `\manysubstitutions' may read `\fdInputLine', 
%% but it must not redefine any macros. 
%% Instead, the substitution macros it calls must read results 
%% of previous substitutions as \emph{arguments}.
%% 
%% Another aspect: 
%% the order of substitutions should be easy to 
%% change. Therefore expanding of string macros should rather be 
%% controlled by the way a job is \emph{called}, not right here 
%% at the \emph{definition} of the job. For this reason, 
%% a variant of the sandbox builder expanding some macro was given up. 

%% `setup_substr_cond' is the name space for macros that build
%% sandboxes and initialize arguments for conditional macros. 
\def\setup_substr_cond{setup_substr_cond:}
%% |\MakeSetupSubstringCondition{<id>}[<changes>]{<pattern>}{<more-args>}|
%% % <- TODO allow `%' and ` ' for breaking code lines. 
%% ---same <id>, <changes>, <pattern> as for 
%% `\MakeSubstringConditional' (this is bad, there may be 
%% |\MakeSubstringConditional*{<more-args>}|)---creates the 
%% % <- TODO: store args in \Make...Conditional
%% corresponding sandbox, by default without tilde wrap. 
%% <more-args> may contain `{#1}' to store the string that was tested,
%% also `{<id>}' for calling repetitions and `{<pattern>}' for screen 
%% or log informations. 
\newcommand*{\MakeSetupSubstringCondition}{%
  \afterassignment\mk_setup_substr_cond_san \def\cond_id}
\newcommand*{\mk_setup_substr_cond_san}[1][]{%
  \begingroup \PatternCodes #1\mk_setup_substr_cond}
%% `\begingroup' |\mk_setup_substr_cond{<pattern>}{<more-args>}| 
%% can be directly called by other programmer setup commands after 
%% `\cond_id' and <pattern> have been read:
\def\mk_setup_substr_cond #1#2{%% #1 pattern string, 
  %% #2 additional arguments, e.g., `{#1}' to keep tested string
  \endgroup 
  \expandafter \edef 
   \csname \setup_substr_cond \cond_id \endcsname ##1{%
%       \expandafter \noexpand 
%         \csname \substr_cond \cond_id \endcsname %% 2009/04/10:
      \make_not_expanding_cs{\substr_cond \cond_id}%
%% By `\edef', the name of the substring conditional is stored here 
%% as a single token. The rest of the sandbox follows. 
          ##1\noexpand~#1\dollar_tilde&#2}%
  \let\dollar_tilde\sandbox_dollar}
%% If a tilde `~' has been used instead of `$', the default 
%% is restored. 
\def\sandbox_dollar{$}
\let\dollar_tilde\sandbox_dollar
%% The following general tool |\make_not_expanding_cs| has been used 
%% (many definitions in 'latex.ltx' could have used it): %% 2009/04/10
\def\make_not_expanding_cs#1{%
  \expandafter \noexpand \csname #1\endcsname}
%%
%% === Getting rid of the tildes ===
%% |\let~\TildeGobbles| can be used to suppress dummy patterns 
%% (contained in <split2>) 
%% in `\write'ing or with `\edef'. ... will probably become obsolete 
%% ... however, it is helpful in that you needn't care 
%% whether there is a dummy wrap left at all. (2009/04/13)
\newcommand{\TildeGobbles}{}       \def\TildeGobbles#1${} 
%% |\RemoveDummyPattern| is used to remove the dummy pattern 
%% \emph{immediately}, not waiting for `\write'ing
%% or other ``total'' expansion:   %% 2009/04/13
\newcommand{\RemoveDummyPattern}{} \def\RemoveDummyPattern#1~#2${#1}
%% |\RemoveDummyPatternArg<macro>{<arg>}| executes 
%% `\RemoveDummyPattern' in the next argument: 
\newcommand*{\RemoveDummyPatternArg}[2]{% 
  \expandafter #1\expandafter {\RemoveDummyPattern #2}} 
%% |\RemoveTilde| is used to remove the tilde that separated 
%% the dummy pattern from <split1>. 
% %% An alternative policy is to pass 
% %% <target> (as an argument) to the parsing macro.
\newcommand{\RemoveTilde}{} \def\RemoveTilde#1~{#1}
%% |\RemoveTildeArg<macro>{<arg>}| executes `\RemoveTilde' 
%% in the next argument: 
\newcommand*{\RemoveTildeArg}[2]{% 
  \expandafter #1\expandafter {\RemoveTilde #2}} 
%%
%% === Calling conditionals ===
%% |\ProcessStringWith{<target-string>}{<id>}| builds the sandbox 
%% to search <target-string> for the <pattern> associated with the 
%% parser-conditional that is identified by <id>, the sandbox then 
%% calls the parser. 
\newcommand*{\ProcessStringWith}[2]{%
  \csname \setup_substr_cond #2\endcsname{#1}}
%% |\ProcessExpandedWith{<string-macro>}{<id>}| does the same but with 
%% a \emph{macro} (like `\fdInputLine' or `\OutputString') in which 
%% the string to be tested is stored.
\newcommand*{\ProcessExpandedWith}[2]{%
  \csname \setup_substr_cond #2\expandafter \endcsname
    \expandafter{#1}}
%% I would have preferred the reversed order of arguments which seems 
%% to be more natural, but the present is more efficient. 
%% Macros with reversed order are currently stored after `\endinput' 
%% in section~\ref{sec:pondered}, may be they once return. 
%%
%% Anyway, most desired will be |\ProcessInputWith{<id>}| just 
%% applying to `\fdInputLine':
\newcommand*{\ProcessInputWith}[1]{%
  \csname \setup_substr_cond #1\expandafter \endcsname
    \expandafter{\fdInputLine}}
%% (Definition almost copied for efficiency.)
  %% TODO: error when undefined 2009/04/07
%%
%% === Copy jobs ===
%% A job identifier <id> may also be considered a mere \emph{hook}, 
%% a \emph{placeholder} for a parsing job. What function actually is 
%% called may depend on conditions that change while reading the 
%% <input> file. %%% On a certain condition, 
%% |\CopyFDconditionFromTo{<id1>}{<id2>}| 
%% \emph{creates or redefines a sandbox builder} with identifier <id2> 
%% that afterwards behaves like the sandbox builder <id1>. 
%% So you can store a certain behaviour as <id1> in advance in order 
%% once to change the behaviour of <id2> into that of <id1>. 
\newcommand*{\CopyFDconditionFromTo}[2]{%
  \expandafter \let 
    \csname \setup_substr_cond #2\expandafter \endcsname 
      \csname \setup_substr_cond #1\endcsname}
%% (Only the \emph{sandbox} is copied here---what about 
%% changing conditionals?) %% TODO 
%%
%% An ``almost'' example is typesetting documentation from a package 
%% file where the ``Legalese'' header might be typeset verbatim 
%% although it is marked as ``comment.'' (The present %% 2009/04/07
%% example changes ``hand-made'' macros instead.)
%%
%% This feature could have been placed more below as a ``programming 
%% tool.''
%%
%%  == Programming tools ==
%% === Tails of conditionals ===
%% \label{sec:tails}
%% When creating complex \emph{expandable} conditionals, 
%% this may amount to have primitive `\if' ... `\fi' conditionals 
%% nested quite deeply, once perhaps too deep for \TeX's memory. 
%% To avoid this, you can apply the common `\expandafter' trick 
%% which finishes the current `\if' ... `\fi' before an inside 
%% macro is executed (cf. \TeX book p.~219 on ``tail recursion'').
%%
%% Internally tests whether certain strings are present at certain 
%% places will be carried out by tests on emptiness or 
%% onwards) on starting with `~'. E.g., 
%% ``#1~=~<split1> empty'' indicates that either the <pattern> 
%% starts a line or the line is empty altogether (this must be 
%% decided by another test). 
%%
%% |\IfFDempty{<arg>}{<when-empty>}{<when-not-empty>}|
%% is used to test <arg> on emptyness (without expanding it): 
\newcommand*{\IfFDempty}[1]{%
  \ifx$#1$\expandafter \@firstoftwo  \else
          \expandafter \@secondoftwo \fi}
%% |\IfFDinputEmpty{<when-empty>}{<when-not-empty>}| is a variant of 
%% the previous to execute <when-empty> if the loop processing <input> 
%% finds an empty line---otherwise <when-not-empty>.
\newcommand*{\IfFDinputEmpty}{%
  \ifx\fdInputLine\@empty \expandafter \@firstoftwo  \else
                          \expandafter \@secondoftwo \fi}
%% |\IfFDdollar{<arg>}{<when-empty>}{<when-not-empty>}| 
%% is another variant, testing <split2> for being `$', 
%% main indicator of there is a match anywhere in <target> 
%% (as opposed to starting or ending match):
\newcommand*{\IfFDdollar}[1]{%
  \ifx$#1\expandafter \@firstoftwo  \else
         \expandafter \@secondoftwo \fi}
%% It is exemplified and explained in section~\ref{sec:replchain}.
%% (The whole policy requires that `~' remains active in any 
%%  testing macros here!)
%%
%% However, you might always just type the replacement text 
%% (in one line) instead of 
%% such an `\If'\,... (for efficiency \dots)
%%
%% If expandability is not desired, you can just chain macros that 
%% rework (so re-define) `\OutputString' or so. 
%%
%% 2009/04/11: tending towards combining ...
%% Keeping empty input and empty arguments apart is useful in that 
%% \emph{one} test of emptiness per input line should suffice---it
%% may be left open whether this should be the first of all tests 
%% \dots
%%
%% === Line counter ===
%% A \LaTeX\ counter |fdInputLine| may be useful for screen or log 
%% messages, moreover you can use it to control processing of the 
%% <input> file ``from outside,'' not dependent on what the parsing 
%% macros find. The header of the file might be typeset verbatim, 
%% but we may be too lazy to define the ``header'' in terms of 
%% what is in the file. We just decide that the first ... lines 
%% are the ``header,'' even without counting just trying whether 
%% the output is fine. It may be necessary to change that number 
%% manually when the header changes. 
%% 
%% You also can insert lines in <output> 
%% which have no counterpart in <input>---if you know what you are 
%% doing. With 'makedoc', there is a hook `\EveryComment' that can 
%% be used to issue commands ``from outside'' at a place where 
%% executing the command is safe or appropriate. 
\newcounter{fdInputLine}
%% You then must insert |\CountInputLines| in the second argument 
%% of `\ProcessFileWith' (or in a macro called from there) 
%% so that the counter is stepped. %% TODO!? 2009/04/07
\newcommand*{\CountInputLines}{\global\advance\c@fdInputLine\@ne}
%% At present %% 2009/04/07 TODO 
%% the counter is reset by `\ProcessFileWith', this may change. 
%%
%% |\IfInputLine{<relation><number>}{<true>}{<false>}|, when called 
%% from the processing loop (second argument of `\ProcessFileWith')
%% issues <true> commands if `\value{fdInputLine}<relation><number>' 
%% is true, otherwise <false>. <relation> may usually be just `='. 
\newcommand*{\IfInputLine}[1]{%
  \ifnum\c@fdInputLine#1\relax \expandafter \@firstoftwo
  \else                        \expandafter \@secondoftwo \fi}
%%
%% === The ``identity job'' `LEAVE' ===
%% \label{sec:LEAVE}
%% The job with identifier |LEAVE| 
%% \emph{leaves} an (expandable) chain of jobs 
%% (as expandable replacement in section~\ref{sec:replchain}) 
%% and \emph{leaves} the processed string without changing it 
%% and without the braces enclosing it:
\expandafter \let 
  \csname \setup_substr_cond LEAVE\endcsname \@firstofone
%% I.e., `\ProcessStringWith{<string>}{LEAVE}' expands to <string> 
%% ... \ProcessStringWith{(Indeed!)}{LEAVE}

%%  == Setup for expandable chains of replacements ==
%% \label{sec:replchain}%% TODO makedoc: provide less visible label/ref 2009/04/11 
%% By the following means, you can create macros 
%% (`\Transform' among them) such that, e.g., 
%% \[`\edef\OutputString{\Transform{<string>}}'\] renders `\OutputString' 
%% the result of applying a chain (sequence) of stringwise replacements 
%% to <string>. 
%% You can even write a transformed input <string> to a file 
%% without defining anything anything after `\read to'\,.\,.\,.
%% In this case however, you don't get any statistical message 
%% about what happened or not. With `\edef\OutputString' you can at 
%% least issue some `changed!' or `left!' (maybe `\message{!}' vs.\ 
%% `\message{.}'). 
%% There is an application in 'makedoc' for ``typographical upgrading'' 
%% from plain text to \TeX\ input. 
%%
%% |\repl_all_chain_expandable| will be the backbone of the 
%% replacements. It is called by some parsing macro <parser>
%% and receives from the latter <split1>~=~#1 and <split2>~=~#2. 
%% #3 is the result of what happened so far. 
\def\repl_all_chain_expandable#1#2#3#4#5#6{%
  %% #1, #2 splits, #3 past,   #4 substitute, 
  %% #5 repeat parser,         #6 pass to 
%   \ifx~#2\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi 
%% The previous line would be somewhat faster, but let us exemplify 
%% `\IfFDdollar' from section~\ref{sec:tails} instead: 
  \IfFDdollar{#2}%
%% If #2 starts with `$'---with category code 3, ``math shift''!, 
%% it \emph{is} `$', due to not reading `$' 
%% from input with its standard category code 3
%% and the sandbox construction (where `$' appears with its standard 
%% category code). %% TODO might be explained earlier 2009/04/11
%%                 %%      or refer to here. 
%% And this is the case \emph{exactly} when the <pattern> from 
%% <parser> didn't match, again due to the input category codes. 
%% Now on \emph{no} match, the sandbox builder #6 is called 
%% with target string #3#1 where the last tested string is attached
%% to previous results. The ending `~' is removed, #6 inserts a new 
%% wrap for the new dummy pattern. 
             {\RemoveTildeArg #6{#3#1}}%
%% Otherwise ... the \emph{sandbox builder} <sandbox>
%% (that will be shown below) that called <parser> 
%% initialized #5 to be that <parser> itself. (<parser> otherwise 
%% wouldn't know who it is.) So <parser> calls itself with another sandbox 
%% `#2&'. Note that #2 contains \lq`~<pattern>$'\rq\ due to the initial 
%% <sandbox> building. 
             {#5#2&{#3#1#4}{#4}#5#6}}
%% #4 is the replacement string that <sandbox> passed to <parse>. 
%% The first argument after the `&' is previous stuff plus 
%% the recently skipped <split1> 
%% plus #4 replacing the string <pattern> that was matched. 
%% 
%% Finally, #5 and #6 again ``recall'' <parser> and the sandbox 
%% builder to which to change in case of no other match. 
%%
%% % TODO move following up!? 2009/04/11
%% |\MakeExpandableAllReplacer{<id>}{<pattern>}{<replace>}{<id-next>}| 
%% creates sandbox and parser with common identifier <id> and search 
%% pattern <pattern>. Each occurrence of <pattern> will be replaced by 
%% <replace>. When <pattern> is not found, the sandbox builder for 
%% <id-next> is called. This may be another replacing macro of the 
%% same kind. To return the result without further transformations, 
%% call job `LEAVE' (section~\ref{sec:LEAVE}).
\newcommand*{\MakeExpandableAllReplacer}{%
  \afterassignment\mk_setup_xpdbl_all_repl_san
  \def\cond_id}
%% ... usual intermezzo for reading patterns with non-standard 
%% category codes, this time we read \emph{two} patterns \dots
\newcommand*{\mk_setup_xpdbl_all_repl_san}[1][]{%
  \begingroup \PatternCodes #1\mk_setup_xpdbl_all_repl}
%% Here comes the real work. 
\newcommand*{\mk_setup_xpdbl_all_repl}[3]{%
  %% #1 pattern, #2 substitute, #3 pass to
  \endgroup
%% We take pains to call next jobs by single 
%% command strings and store them this way, not by `\csname', 
%% as `\ProcessStringWith' would do it. `\edef\@tempa' 
%% is used for this purpose, but \dots
    \edef\@tempa{%
      \noexpand\mk_setup_substr_cond{#1}{%
        {}{#2}%
        \noexpand\noexpand
%% That `\edef\@tempa' must \emph{not expand} the controll 
%% words after they have been computed from `\csname' etc. 
%% Moreover, expansion of the parser commands 
%% must be avoided another time, when `\@tempa' is executed. 
          \make_not_expanding_cs{\substr_cond\cond_id}%
        \noexpand\noexpand
          \make_not_expanding_cs{\setup_substr_cond #3}}}%
%% Those internal setup commands start with `\endgroup' to switch back 
%% to standard category codes. We must match them here by 
%% `\begingroup'.
    \begingroup \@tempa
    \begingroup \mk_substr_cond{#1}{%
      \repl_all_chain_expandable{##1}{##2}}}
%% The final command is the one that we explained first. %% TODO 2009/04/11 
%%
%% Support for dozens of replacements in one sequence 
%% and for screen messages 
%% must wait for another release, sorry! %% TODO 2009/04/11
%%
%%  == Leave package mode ==
%% We restore the underscore `_' for math subscripts. 
%% (This might better depend on something \dots) %% TODO 2009/04/07
\catcode`\_=8   %% restores underscore use for subscripts

\endinput 
%% \TeX\ ignores the rest of the file when it is \emph{input} 
%% ``in the sense of `\input''', as opposed to just reading 
%% the file line by line to a macro like `\fdInputLine'. 
%%
%% == Pondered ==
%% \label{sec:pondered}
  %% TODO abbreviated commands (aliases) \MkSubstrCond...
  %% TODO \@onlypreamble!?
\newcommand*{\ApplySubstringConditional}[1]{%
  %% #1 identifier; text to be searched expected next
  \csname setup_substr_cond:#1\endcsname}
\newcommand*{\ApplySubstringConditionalToExpanded}[1]{% 2009/03/31+
  \csname setup_substr_cond:#1\expandafter \endcsname \expandafter}
\newcommand*{\ApplySubstringConditionalToInputString}[1]{% 2009/03/31+
  \csname setup_substr_cond:#1\expandafter \endcsname 
    \expandafter {\fdInputLine}}
  %% TODO or `\OutputString', even `\read' to `\OutputString'!?
% \newcommand*{\ApplySubstringConditionalToExpanded}[2]{%
%   %% note: without assignments, robust!
%   %% BUT the `\csname ... \expandafter \endcsname' method is faster
%   \expandafter \reversed_apply_substr_cond
%     \expandafter {#2}{#1}}
% \newcommand*{\reversed_apply_substr_cond}[2]{%
%   \ApplySubstringConditional{#2}{#1}}
  %% ODER: 
% \newcommand*{\expand_attach_arg}[2]{%% 2009/03/31
%   %% #1 command with previous args, TODO cf. LaTeX3
%   \expandafter \attach_arg \expandafter {#1}{#2}}
%   %% actually #1 may contain more than one token, 
%   %% only first expanded
% \newcommand*{\attach_arg}[2]{#2{#1}}
% \newcommand*{\ApplySubstringConditionalToExpanded}[2]{%
%   \expandafter \attach_arg \expandafter 
%     {#2}{\ApplySubstringConditional{#1}}}
%%
%%
%%
%% == VERSION HISTORY ==
%%
v0.1   2009/04/03   very first version, tested on morgan.sty
v0.2   2009/04/05   counter fdInputLine, \ProvidesFile moved from 
                    \ProcessFile to \ResultFile, \CopyFD...,
                    category section first, more sectioning, 
                    suppressing empty code lines before section 
                    titles; discussion, \Delimiters
       2009/04/06   more discussion
       2009/04/07   more discussion, factored \WriteProvides out from 
                    \ResultFile, \ProcessExpandedWith corrected
       2009/04/08   \InputString -> \fdInputline; 
                    removed \ignorespaces 
       2009/04/09   \WhenInputLine[2] -> \IfInputline[3], 
                    \ProcessInputWith, typos, 
                    \WriteProvides message `with'
       2009/04/10   \make_not_expanding_cs
                    DISCOVERED ``IF SUBSTRING'' ALGORITHM WRONG
                    (<str1><str2><str1> in <str1><str2>)
v0.3   2009/04/11   SOME THINGS GIVEN UP EARLIER WILL BE REMOVED, 
                    TO BE STORED IN THE COPY AS OF 2009/04/10
                    mainly: sandbox setup (tilde/dollar) 
                    REAL ADDITION: setup for expandable replacing 
       2009/04/12   played with `chain' vs. `sequence';
                    plain `...', `cf.', `etc.' for `mdcorr.cfg'
       2009/04/13   \RemoveTilde...
       2009/04/15   reworked text, same mistake \in@