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#############################################################################
##
## This file is part of GAP, a system for computational discrete algebra.
## This file's authors include Frank Celler, Alexander Hulpke, Greg Gamble.
##
## Copyright of GAP belongs to its developers, whose names are too numerous
## to list here. Please refer to the COPYRIGHT file for details.
##
## SPDX-License-Identifier: GPL-2.0-or-later
##
## The files helpt2t.g{d,i} contain the function to convert TeX source
## code written in `gapmacro.tex' style into text for the "screen" online
## help viewer.
##
#############################################################################
##
#F HELP_PRINT_SECTION( <book>, <chapter>, <section> [,<key>] ) . print entry
##
## key is a function name
##
## main function to extract the help text for a topic from GAP main help
##
HELP_FLUSHRIGHT:=true;
InstallGlobalFunction(HELP_PRINT_SECTION_TEXT, function(arg)
local book, chapter, section, key, subkey, MatchKey, ssectypes,
info, chap, filename, stream, p, q, lico,
line, i, j, lines, IsIgnoredLine, macro, macroarg, tail,
ttenv, text, verbatim, nontex, item, initem, displaymath, align,
lastblank, singleline, rund, SetArg, FlushLeft, Gather,
width, buff, EmptyLine, ll, start, keynotfound, verb, URLends;
# flush buffer ... then add empty line
EmptyLine := function()
if Length(buff)>0 then
Add(lines,buff);
if keynotfound then start := start+1; fi;
buff:="";
fi;
if not lastblank then
Add(lines,"");
if keynotfound then start := start+1; fi;
lastblank:=true;
fi;
end;
# get argument in {...} at front of tail (need to handle nested {}'s)
# ... macroarg is set with the argument matched and tail set to the rest
SetArg := function()
local level, p;
while 0<Length(tail) and tail[1]=' ' do
tail := tail{[2..Length(tail)]};
od;
if IsEmpty(tail) then
macroarg:="";
elif tail[1]<>'{' then
macroarg:=tail{[1]};
tail := tail{[2..Length(tail)]};
else
level := 0;
p := 2;
while true do
if p > Length(tail) then
macroarg:=""; # Forget it ... can't match braces
break;
elif tail[p] = '{' then
level := level+1;
elif tail[p] = '}' then
if level = 0 then
macroarg := tail{[2..p-1]};
tail := tail{[p+1..Length(tail)]};
break;
else
level := level-1;
fi;
fi;
p := p+1;
od;
fi;
return;
end;
FlushLeft := function(s)
local p;
p:=1;
while p<=Length(s) and s[p]=' ' do
p:=p+1;
od;
return s{[p..Length(s)]};
end;
IsIgnoredLine := function(line)
# this is meant to catch lines that except for some initial
# whitespace are of form: "\begingroup ... %"
# or: "{\obeylines ... %" or: "{%" or "}%"
if not displaymath and 1<Length(line) and Last(line) = '%' then
line := FlushLeft(line);
return 1=Length(line) or
line{[1..Length(line)-1]} in ["{", "}"] or
line{[1..2]}="{\\" and IsAlphaChar(line[3]) or
line[1]='\\' and IsAlphaChar(line[2]);
else
return false;
fi;
end;
# Scrubs a % from the beginning of the line in nontex mode
# and joins lines ending in %
Gather := function()
local nextline;
while line <> fail do
if nontex and 0<Length(line) and line[1] = '%' then
line := line{[2..Length(line)]};
fi;
if line="$$" then
# toggle displaymath
displaymath := not displaymath;
align := false;
EmptyLine();
elif displaymath and
((align and line="}") or (not align and line="\\matrix{")) then
align := not align; # toggle align
else
break;
fi;
line := Chomp( ReadLine(stream) );
od;
# a '%' at end-of-line indicates a continuation
while line<> fail and 0<Length(line) and Last(line)='%' do
line := line{[1..Length(line)-1]};
repeat
nextline := ReadLine(stream);
if nontex and nextline<>fail and
0<Length(nextline) and nextline[1] = '%' then
nextline := nextline{[2..Length(nextline)]};
fi;
until nextline=fail or 0<Length(nextline) and nextline[1]<>'%';
if nextline=fail then
break;
else
nextline := Chomp(nextline);
fi;
line := Concatenation(line, FlushLeft(nextline));
od;
end;
# Returns true if <s> (a string = <lico>) matches
# <type> (a ssectype of <key>), or else, false.
# ... <type> is a list of strings that must match <s> in sequence,
# the following strings in <type> have special meaning:
# " " means skip blanks until the next non-blank and the
# next string must match at position 1.
# "^X" for any X, means scan what remains of string and
# check there are no X chars.
MatchKey := function(s, type)
local p, q, str;
q:=0;
for str in type do
if str=" " then
s:=FlushLeft(s); q:=1;
elif str[1]='^' then
if Position(s, str[2]) <> fail then
return false;
fi;
q:=0;
else
p:=PositionSublist(s, str);
if p=fail or (q=1 and p<>1) then
return false;
fi;
s:=s{[p+Length(str)..Length(s)]}; q:=0;
fi;
od;
return true;
end;
width:=SizeScreen()[1]-6;
book:=arg[1];
chapter:=arg[2];
section:=arg[3];
# did we get the section only via a keyword?
if Length(arg)>3 then
key:=arg[4];
p:=Position(key,'!');
if p=fail then
subkey:="";
else
subkey:=key{[p+1..Length(key)]};
key:=key{[1..p-1]};
fi;
# define subsection matching types: ssectypes
# (ignoring any @... component)
if subkey="" then
ssectypes :=
[ # \><key>(...)
[ " ", key, " ", "(", ")", "^!"],
# \>`<key>' V
[ Concatenation("`",key,"' "), "^{", " ", "V" ],
# \>`...'{<key>}
[ " ", "`", "'", " ", Concatenation("{",key,"}"), "^!" ] ];
else
ssectypes :=
[ # \><key>(...)!{<subkey>}
[ " ", key, " ", "(", ")", " ", "!", " ",
Concatenation("{", subkey, "}") ],
# \>`...'{<key>!<subkey>}
[ " ", "`", "'", " ", Concatenation("{",key,"!",subkey,"}"), "^!" ],
# \>`...'{<key>}!{<subkey>}
[ " ", "`", "'", " ", Concatenation("{",key,"}!{",subkey,"}"), "^!"] ];
fi;
else
key:=fail;
fi;
# get the chapter info
info := HELP_BOOK_INFO(book);
chap := HELP_CHAPTER_INFO( book, chapter );
if chap = fail then
return fail;
fi;
# store lines
lines := [];
# open the stream and read in the help
filename := Filename( info.directories, info.filenames[chapter] );
stream := StringStreamInputTextFile(filename);
if section = 0 then
SeekPositionStream( stream, chap[1] );
Add( lines, FILLED_LINE( info.chapters[chapter], info.bookname, '_' ) );
else
SeekPositionStream( stream, chap[2][section] );
Add( lines, FILLED_LINE( info.sections[chapter][section],
info.chapters[chapter], '_' ) );
#The repeat loop was a ``workaround'' for a deficiency in
#`SeekPositionStream' which has now been fixed by FL
#... so now `ReadLine' need only be executed once. - GG
#repeat
# On UNIX with files not in DOS format, stream positioning works
# and so we have the \Section... line on the first iteration.
# On other architectures or with a DOS format file, stream positioning
# might get confused due to the CRLF problem (typically just one
# extra iteration is necessary to get past the LF). We continue
# reading until we know we have actually reached the line.
line:=ReadLine(stream);
#until MATCH_BEGIN( line, HELP_SECTION_BEGIN ) and
# # A section starts ... ensure it is the right section:
# MATCH_BEGIN( line{[10..Length(line)]},
# info.sections[chapter][section] );
fi;
# Initialise a number of variables before the main section-scanning loop
singleline:=0; # 0 => paragraph-mode: append line to buff, when buff
# gets longer than width, break into lines of
# length width.
# 1 => obeylines-mode: simply add line to lines.
# 2 => obeylines-mode but ensuring no blank line is
# inserted between lines.
buff:=""; # In paragraph-mode, line is buffered in buff before
# being broken into lines.
lastblank:=false; # Used to avoid having two blank lines in succession.
start := 1; # The section is scanned into lines, but displayed
# from lines[start].
nontex := false; # Set inside %display{nontex} and %display{nonhtml}
# environments, where after removal of an initial
# % (if there is one), text is interpreted normally.
# text-mode and verbatim-mode only differ in the way we treat "||"
text:=false; # Set inside %display{text}..%enddisplay
verbatim := false; # Set inside each of \begintt..\endtt and
# \beginexample..\endexample
ttenv:=false; # Set inside \begintt..\endtt
item := 0; # Set to 1 in \beginitems..\enditems and
# to 1 (in \item entry) or 2 (in \itemitem entry)
# of \beginlist..\endlist. Otherwise, set to 0.
displaymath:=false;# Set inside $$ .. $$ for maths displays delimited
# by $$ lines i.e. lines with *only* $$.
align := false; # Set inside displaymath in \matrix{ .. }
keynotfound := false; # In case it is not set in the while loop
line := ReadLine(stream);
while line <> fail and not MATCH_BEGIN( line, HELP_SECTION_BEGIN ) do
line := Chomp(line);
if nontex and 0 < Length(line) and line[1] = '%' and
not MATCH_BEGIN( line, "%enddisplay" ) then
line := line{[2..Length(line)]};
fi;
if key<>fail then
# we got the section only via a keyword. Ignore the first
# part of the section and start only at the interesting
# bits. When the key and subkey are found, key is set
# to fail to disable skip mode i.e. key=fail => key found.
# *Note* key and subkey have come from matches of (partial)
# words (that the user entered) with the .six file,
# so we need an *exact* match with key and subkey.
# We do *not* use MATCH_BEGIN here.
p:=PositionSublist(line,"\\>");
if p<>fail then
Gather(); # needed in case of continuations
lico:=FlushLeft(NormalizedWhitespace(line{[p+2..Length(line)]}));
if ForAny(ssectypes, type -> MatchKey(lico, type)) then
key := fail;
Info(InfoWarning, 2, "Matched line: ", line);
fi;
fi;
fi;
keynotfound := key<>fail;
# blanks lines are ok
if 0 = Length(line) then
if not verbatim and not text then
EmptyLine();
fi;
elif verbatim then
if MATCH_BEGIN(line,"\\endtt") then
verbatim := false;
ttenv := false;
lastblank:=false;
EmptyLine();
elif ( not ttenv and MATCH_BEGIN(line,"\\endexample") ) then
verbatim := false;
ttenv := false;
lastblank:=false;
buff := Concatenation (ListWithIdenticalEntries (width, "-"));
EmptyLine();
else
lastblank:=true;
# Any "||" actually represents "|"
p := PositionSublist(line,"||");
while p<> fail do
line:=Concatenation(line{[1..p]}, line{[p+2..Length(line)]});
p := PositionSublist(line,"||",p);
od;
Add( lines, line );
if keynotfound then start := start+1; fi;
fi;
elif text then
if MATCH_BEGIN(line,"%enddisplay") then
text := false;
lastblank:=false;
EmptyLine();
elif line[1] = '%' then
Add( lines, line{[2..Length(line)]} );
if keynotfound then start := start+1; fi;
else
lastblank:=false;
Add( lines, line );
if keynotfound then start := start+1; fi;
fi;
# ignore answers to exercises
elif MATCH_BEGIN(line,"\\answer") then
repeat
line := ReadLine(stream);
until line = fail or line = "\n" or line = "\r\n";
# displays for text and HTML that need are interpreted
# normally (except any initial % is first removed)
elif MATCH_BEGIN(line,"%display{nontex}")
or MATCH_BEGIN(line,"%display{nonhtml}") then
nontex := true;
text := false;
verbatim := false;
# ignore displays for TeX or HTML
elif MATCH_BEGIN(line,"%display{tex}")
or MATCH_BEGIN(line,"%display{nontext}")
or MATCH_BEGIN(line,"%display{html}")
or MATCH_BEGIN(line,"%display{jpeg}") then
repeat
line := ReadLine(stream);
until line = fail
or MATCH_BEGIN(line,"%display{text}")
or MATCH_BEGIN(line,"%display{nontex}")
or MATCH_BEGIN(line,"%enddisplay");
if MATCH_BEGIN(line,"%display{text}") then
text := true;
EmptyLine();
elif MATCH_BEGIN(line,"%display{nontex}") then
nontex := true;
fi;
elif MATCH_BEGIN(line,"\\index{")
or MATCH_BEGIN(line,"\\indextt{")
or MATCH_BEGIN(line,"\\atindex{") then
# A '%' at end-of-line indicates a continuation
while line <> fail and line <> "" and
(line[1] = '%' or Last(line) = '%') do
line := Chomp( ReadLine(stream) );
od;
line:="";
# example environments
elif MATCH_BEGIN(line,"\\beginexample") then
verbatim := true;
ttenv := false;
EmptyLine();
buff := Concatenation (
Concatenation (ListWithIdenticalEntries (QuoInt (width-9, 2), "-")),
" Example ",
Concatenation (ListWithIdenticalEntries (width - 9 - QuoInt (width-9, 2), "-")));
EmptyLine();
elif MATCH_BEGIN(line,"\\begintt") then
ttenv := true;
verbatim := true;
EmptyLine();
elif MATCH_BEGIN(line,"\\endexample") then # Just in case ...
verbatim := false;
lastblank:=false;
buff := Concatenation (ListWithIdenticalEntries (width-9, "-"));
EmptyLine();
elif MATCH_BEGIN(line,"\\endtt") then
verbatim := false;
lastblank:=false;
EmptyLine();
elif MATCH_BEGIN(line,"%display{text}") then
text := true;
EmptyLine();
elif MATCH_BEGIN(line,"%enddisplay") then # Just in case
text := false;
nontex := false;
lastblank:=false;
EmptyLine();
elif MATCH_BEGIN(line,"\\beginitems")
or MATCH_BEGIN(line,"\\beginlist") then
item:=1;
EmptyLine();
elif MATCH_BEGIN(line,"\\enditems")
or MATCH_BEGIN(line,"\\endlist") then
item:=0;
EmptyLine();
# ignore lines beginning with '%' except if in text
# or verbatim modes (which we have already dealt with)
# or if in nontex mode (which we deal with below);
# also ignore specific lines ending in a '%'
# (other than the lines mentioned a '%' at end-of-line
# indicates a continuation)
elif not nontex and line[1] = '%' or
# this is meant to exclude lines that after some
# initial whitespace are of form: "\begingroup ... %"
# or: "{\obeylines ... %" or "{%" or "}%"
IsIgnoredLine(line) then
;
# use everything else
else
if not text and not verbatim then
Gather();
if MATCH_BEGIN(line,"\\exercise") then
line{[1..9]} := "EXERCISE:";
elif MATCH_BEGIN(line,"\\danger") then
line{[1..7]} := "DANGER:";
# cope with `\>' entries
elif MATCH_BEGIN(line,"\\>") or
MATCH_BEGIN(line,"\\)") then
displaymath := false; # in case a $$ wasn't matched
if singleline<>2 then
# force separator if the line above was not
# already a header
EmptyLine();
fi;
singleline:=2; # we want it on a single line and it
# may have a `cat' letter
rund:=line[2]=')';
line:=line{[3..Length(line)]}; # remove `>'
if rund then
if line[1]='{' then
tail:=line;
SetArg();
if macroarg="" then #No matching brace
line := line{[2..Length(line)]};#absorb '{' anyway
else
line := Concatenation(macroarg,"\\,",tail);
fi;
fi;
if 5<Length(line) and line{[1..6]}="\\fmark" then
line:=Concatenation(">",line{[7..Length(line)]});
fi;
# remove an \hfill if present
line := ReplacedString(line, "\\hfill", "");
else
while 0<Length(line) and line[1]=' ' do
line:=line{[2..Length(line)]};
od;
# remove @... label/index stuff from line
if 0<Length(line) and line[1]='`' then
# types: \>`...'{...}
# \>`...'{...}!{...} -> \>`...'{...!...}
# \>`...'{...}@{...} -> \>`...'{...}
# \>`...'{...}@`...' -> \>`...'{...}
p:=PositionSublist(line,"}!{");
if p<>fail then
line:=Concatenation(line{[1..p-1]},
line{[p+3..Length(line)]});
fi;
p:=Position(line,'@');
if p<>fail then
if p<Length(line) and line[p+1]='`' then
q:=Position(tail,'\'');
if q<>fail then
line:=Concatenation(
line{[1..p-1]},
line{[q+1..Length(line)]});
fi;
else
tail:=line{[p+1..Length(line)]};
SetArg(); # remove {...}
if macroarg<>"" then
line:=Concatenation(line{[1..p-1]},tail);
fi;
fi;
fi;
fi;
line:=Concatenation("> ",line); # add the leading `>'
fi;
elif displaymath then
singleline := 1;
if align then
# Should we check for \& here?
# ... my feeling is that \& should not be allowed
# (there are too many other places where it can
# cause problems) - GG
line := ReplacedString(line, "&", "");
fi;
else
# by default we don't request single lines
singleline:=0;
fi;
# If we wanted to support \~ accents ...
# (ties ~ as opposed to accents \~)
#p:=Position(line,'~');
#while p<>fail do
# if p=1 or line[p-1] <> '\\' then
# line[p]:=' ';
# fi;
# p:=Position(line,'~',p);
#od;
if item>0 then
line:=FlushLeft(line);
p := Position(line,'&');
initem := p=fail;
if not initem then
if singleline=2 then
line[p] := ' ';
else
EmptyLine();
tail:= FlushLeft(line{[p+1..Length(line)]});
line:=Concatenation(line{[1..p-1]},"{\\break}",tail);
singleline:=0;
fi;
fi;
fi;
# some further handling of TeX macros
p:=Position(line,'\\');
while p<>fail do
tail:=line{[p+1..Length(line)]};
line:=line{[1..p-1]};
macroarg := "";
macro := "";
if tail = "" then
# if line ends in a \ indicating a continuation as
# ... we put it back
line[p] := '\\';
p := fail;
elif not IsAlphaChar(tail[1]) then
# Single character macros
macro := tail{[1]};
tail := tail{[2..Length(tail)]};
# escaped chars \ { } $ & _ % and <space>
if macro[1] in "\\{}$#&_% " then
;
# non-alpha accents
elif macro[1] in "'`=^.\"~" then
# \. could be an accent or multiplication
# ... we treat them the same. We don't support \~.
if Length(line)>0 and Last(line)='{' and
Length(tail)>=2 and tail[2]='}' then
# We assume they appear as e.g.: {\'a}
line:=line{[1..Length(line)-1]};
macroarg:=tail{[1]};
tail:=tail{[3..Length(tail)]};
fi;
if macro = "=" then
macro := "-";
elif macro = "~" then
macro := ""; # just omit it
fi;
# fine spacing macros ... we just ignore
elif macro[1] in "!," then
macro := "";
elif macro[1] in ";" then
macro := " ";
# shouldn't get these here ...
elif macro[1] in ">)" then
macro := Concatenation(" ",macro);
# any we missed? ... just treat as escaped char
else
;
fi;
else
# Multi-character macros
q:=1;
while q<=Length(tail) and IsAlphaChar(tail[q]) do
q:=q+1;
od;
macro:=tail{[1..q-1]};
tail:=tail{[q..Length(tail)]};
# accents have args ... deal with that
if macro in ["accent", "c", "d", "b",
"t", "u", "v", "H"] then
if macro="accent" then
q:=1;
while q<=Length(tail) and IsDigitChar(tail[q]) do
q:=q+1;
od;
macro:=tail{[1..q-1]};
tail:=tail{[q..Length(tail)]};
fi;
if macro="19" and Length(tail)>=2 and
tail{[1..2]}="{}" then
tail:=tail{[3..Length(tail)]};
else
while 0<Length(tail) and tail[1]=' ' do
tail:=tail{[2..Length(tail)]};
od;
if 1<Length(tail) and macro="t" then
macroarg:=tail{[1..2]};
tail:=tail{[3..Length(tail)]};
elif 0<Length(tail) then
macroarg:=tail{[1]};
tail:=tail{[2..Length(tail)]};
fi;
fi;
fi;
# If macro enclosed in {..} or $..$ remove them
if Length(line)>0 and Length(tail)>0 and
((Last(line)='{' and tail[1]='}') or
(Last(line)='$' and tail[1]='$')) then
line:=line{[1..Length(line)-1]};
tail:=tail{[2..Length(tail)]};
fi;
# handle some macros
# all the \accentNNN accents including umlaut
# ... macro just contains NNN for these
if macro="18" then
macro:="`";
elif macro="19" then
macro:="'";
elif macro="20" then
macro:="\\v";
elif macro="21" then
macro:="\\u";
elif macro="22" then
macro:="-"; # not elegant
elif macro="94" then
macro:="^";
elif macro="95" then
macro:="."; # not elegant
elif macro="125" or macro="127" then # umlaut
macro:="\"";
# We don't support \accent126 = \~
elif macro="126" then
macro:="";
# alpha accents
elif macro in [ "c", "d", "b", "t" ] then # too hard
macro:=""; # just omit
elif macro="u" or macro="v" then
# put backslash back
macro:=Concatenation("\\",macro);
elif macro="H" then # treat like umlaut
macro:="\"";
# sharp s, ligatures, other specials
elif macro in [ "ss", "oe", "OE", "ae", "AE",
"o", "O", "l", "L" , "i", "j"] then
; # good enough without backslash
elif macro in [ "aa", "AA" ] then
macro := macro{[1]};
elif macro="copyright" then
macro := "(c)";
elif macro in ["GAP", "MOC", "CAS", "ATLAS"] then
; # nothing to do it's right already
elif macro = "calR" then
macro := "R";
elif macro="package" then
SetArg(); # sets macroarg and tail as we need it
macro := "";
elif macro="lq" then
macro:="`";
elif macro="rq" then
macro:="'";
elif macro="pif" then
macro:="'";
elif macro in ["dots","ldots","cdots","vdots"] then
macro:="...";
elif macro="cdot" then
macro:=" . ";
elif macro="dot" then
macro:=".";
elif macro="kernttindent" then
macro:="";
elif macro="enspace" then
macro:="~";
elif macro="quad" then
macro:="~~";
elif macro="qquad" then
macro:="~~~";
elif macro="item" or macro="itemitem" then
EmptyLine();
SetArg();
singleline:=0;
initem:=false;
if macroarg="$-$" then
macroarg:="-";
fi;
# to get rid of any ordered list markup that
# is only interpreted for the HTML version
if macro="itemitem" then
q := Position(tail, '%');
if q <> fail then
tail := tail{[1..q-1]};
fi;
fi;
# we do this so macroarg is scanned for macros
tail:=Concatenation(macroarg,"\\endmacro ",tail);
macroarg:="";
if macro="item" then
item:=1;
macro:="\\item";
else
item:=2;
macro:="~~~~\\item";
fi;
elif macro="endmacro" then
q:=PositionSublist(line,"\\item");
macroarg:=line{[q+5..Length(line)]};
line:=line{[1..q-1]};
macro:="";
tail:=FlushLeft(tail);
# we do this to prevent macroarg expanding
macroarg := ReplacedString(macroarg," ","~");
if Length(macroarg)>=3 then
macroarg:=Concatenation(macroarg,"~");
else
macroarg:=Concatenation(macroarg,"~~~~"){[1..4]};
fi;
# font changing commands
elif macro in ["bsf","sf","bf","rm","cal","sl","it"] then
if Length(line)>0 and Last(line)='{' then
line:=line{[1..Length(line)-1]};
while 0<Length(tail) and tail[1]=' ' do
tail:=tail{[2..Length(tail)]};
od;
tail:=Concatenation("{",tail);
SetArg();
if macroarg<>"" then
if macro="bsf" then
tail:=Concatenation("*",macroarg,"*",tail);
else
tail:=Concatenation(macroarg,tail);
fi;
macroarg:="";
fi;
fi;
macro:="";
elif macro in [ "medskip", "bigskip" ] then
macro:="";
EmptyLine();
elif macro in [ "par", "begingroup", "endgroup" ] then
tail := ""; # assume the rest of the line
macro := ""; # is not intended for our eyes
elif macro="hrule" then
line:= FILLED_LINE("","",'-');
line[1] := '-';
line[Length(line)] := '-';
elif macro="hfill" and align then
macro:="";
elif macro="hfill" then
line:= FILLED_LINE(line,tail,' ');
elif macro="break" then
line:= FILLED_LINE(line,"~ ",' ');
macro:="";
elif macro="cr" then
macro:="";
# math macros
elif macro="langle" or macro="lneqq" then
macro:="<";
elif macro="rangle" then
macro:=">";
elif macro="ne" or macro="neq" then
macro:=" <> ";
elif macro="le" or macro="leq" then
macro:=" <= ";
elif macro="ge" or macro="geq" then
macro:=" >= ";
elif macro="backslash" or macro="setminus" then
macro:="\\";
elif macro="bullet" then
macro:=".";
elif macro="circ" then
macro:="o";
elif macro="mapsto" then
macro:=" |-> ";
elif macro="longmapsto" then
macro:=" |--> ";
elif macro in ["rightarrow", "hookrightarrow", "to"] then
macro:=" -> ";
elif macro="Rightarrow" then
macro:=" => ";
elif macro="iff" then
macro:=" <=> ";
elif macro="vdash" then
macro:=" |- ";
elif macro="times" then
macro:=" x ";
elif macro="in" then
macro:=" in ";
elif macro="gamma" then
macro:="y"; # looks similar!
elif macro="forall" then
macro:=" for all ";
elif macro="exists" then
macro:=" there exists ";
elif macro="mid" then
macro:="|";
elif macro="colon" then
macro:=":";
elif macro="ast" then
macro:="*";
elif macro="lfloor" or macro="lbrack" then
macro:="[";
elif macro="rfloor" or macro="rbrack" then
macro:="]";
elif macro="left" or macro="right" then
macro:="";
if 0<Length(tail) and tail[1]='.' then
tail:=tail{[2..Length(tail)]};
fi;
elif macro="prime" then
# this isn't ideal since ^{\prime} becomes ^'
# ... but a_N^{\prime} becomes a_N^' at least
# showing that the ' belongs to a (rather than N)
macro:="'";
elif macro="cup" then
macro:=" U ";
elif macro="over" then
macro:="/";
elif macro="hbox" then
SetArg();
macro:="";
elif macro="frac" then
SetArg();
macro:=Concatenation(" ",macroarg,"/");
SetArg();
macro:=Concatenation(macro,macroarg," ");
macroarg:="";
elif macro="bmod" then
macro:=" mod ";
elif macro="pmod" then
SetArg();
macro:=Concatenation("(mod ",macroarg,")");
macroarg:="";
elif macro in [ "mathbin", "mathrel", "buildrel",
"mathop", "limits" ] then
macro:=""; # ignore
else
; # display the macro name
fi;
fi;
if macro<>"hfill" and macro<>"hrule" then
line:=Concatenation(line,macro,macroarg,tail);
fi;
p := Length(line) - Length(tail);
if IsEmpty(line) then line:="";fi;
p:=Position(line,'\\',p);
od;
fi;
lastblank:=false;
if singleline=2 then
while Length(line)>width do
p:=width;
while p>=1 and not(line[p] in " ,.>])") do
p:=p-1;
od;
if p = 0 then
p:=width-1;
if IsAlphaChar(line[p]) or IsDigitChar(line[p]) then
Add(lines, Concatenation(line{[1..p]}, "-"));
else
Add(lines, line{[1..p]});
fi;
elif line[p] = ' ' then
Add(lines, line{[1..p-1]});
else
Add(lines, line{[1..p]});
fi;
if keynotfound then start := start+1; fi;
line := Concatenation("~~~~",
FlushLeft(line{[p+1..Length(line)]}) );
od;
# treat trailing `category' letter(s)
p:=Length(line);
if 0<p and line[p] in "CROFPAMV" then
# we assume that the character before the category
# letter(s) is a blank space
if 1<p and line{[p-1..p]} = "AM" then
line:=FILLED_LINE(line{[1..p-2]},line{[p-2..p]},' ');
else
line:=FILLED_LINE(line{[1..p-1]},line{[p-1..p]},' ');
fi;
fi;
Add(lines,line);
if keynotfound then start := start+1; fi;
elif singleline=0 then
if Length(buff)>0 and Last(buff) <> '~' then
Add(buff,' '); # separating ' '
elif item>0 and initem and 0=Length(buff) and
0<Length(line) and line[1]<>'~' then
buff:="~~~~";
fi;
buff:=Concatenation(buff,line);
while Length(buff)>width do # force to fill lines
# find the last space to break
p:=width;
while p>=1 and buff[p] <> ' ' do
p:=p-1;
od;
if p=0 then
# cope with overfull lines
Add(lines,Concatenation(buff{[1..width-1]},"-"));
if keynotfound then start := start+1; fi;
buff:=buff{[width..Length(buff)]};
else
line:=buff{[1..p-1]};
buff:=buff{[p+1..Length(buff)]}; # letter p is the ' '
if HELP_FLUSHRIGHT and ' ' in line then
# remove leading and trailing blanks
ll:=1;
while ll<Length(line) and line[ll]=' ' do
ll:=ll+1;
od;
line:=line{[ll..Length(line)]};
ll:=Length(line);
while ll>0 and line[ll]=' ' do
ll:=ll-1;
od;
line:=line{[1..ll]};
# flush right adjustment, for this the line must
# contain spaces
p:=0;
while ll<width do
p:=Position(line,' ',p);
if p=fail then
# start anew
p:=Position(line,' ',0);
fi;
# if the line actually contains no
# spaces then give up
if p = fail then
break;
fi;
# add a blank
line:=Concatenation(line{[1..p]}, line{[p..ll]});
# avoid to add the next blank just there
ll:=ll+1;
p:=p+1;
while p<=ll and line[p]=' ' do
p:=p+1;
od;
if p>ll then
p:=0;
fi;
od;
fi;
Add(lines,line);
if keynotfound then start := start+1; fi;
if item>0 then
buff := Concatenation( "~~~~", FlushLeft(buff) );
if item=2 then
buff := Concatenation("~~~~",buff);
fi;
fi;
fi;
od;
else
if displaymath then
line := Concatenation("~~~~",line);
fi;
Add(lines,line);
if keynotfound then start := start+1; fi;
fi;
fi;
line := ReadLine(stream);
od;
CloseStream(stream);
# Now we replace ~s by spaces, except in URLs and in `...'
# (a TeX ~ is a tie which for on-line help amounts to an unstretchable space)
verb := false; # Set to true inside `...' (named for LaTeX \verb|...|)
for i in [1 .. Length(lines)] do
# we assume URLs are not broken over lines, URLs don't contain `...'
# environments and `...' environments don't contain URLs
for j in [1 .. Length(lines[i])] do
# replace a sequence of ~s at the beginning of a line by spaces
if lines[i][j] = '~' then
lines[i][j] := ' ';
else
break;
fi;
od;
q := 0;
if verb then
q := Position(lines[i],''');
while q<>fail and q<Length(lines[i]) and lines[i][q+1]=''' do
q := Position(lines[i],''',q+1);
od;
if q=fail then
q := Length(lines[i]);
else
verb := false;
fi;
tail := lines[i]{[q+1..Length(lines[i])]};
line := ReplacedString(lines[i]{[1..q]},"~","\\tilde");
q := Length(line);
lines[i] := Concatenation(line,tail);
fi;
p := PositionSublist(lines[i],"URL{",q);
URLends := [];
while p<>fail do
tail:=lines[i]{[p+3..Length(lines[i])]};
line:=lines[i]{[1..p+2]};
SetArg();
if macroarg="" then # abort ... no matching '}'
lines[i]:=Concatenation(line,tail);
Add(URLends, [p, Length(lines[i])]);
break;
else
lines[i]:=Concatenation(
line,"{",ReplacedString(macroarg,"~","\\tilde"),"}",tail);
fi;
Add(URLends, [p, Length(lines[i]) - Length(tail)]);
p:=PositionSublist(lines[i],"URL{",Length(lines[i]) - Length(tail));
od;
p := q;
while not verb and p < Length(lines[i]) do
while p < Length(lines[i]) do
# this loop sets p to the beginning of the next `...' environment
# ... or sets p = fail if there isn't one
p := Position(lines[i], '`', p);
if p=fail then
break;
fi;
while not IsEmpty(URLends) and p > URLends[1][2] do
URLends := URLends{[2..Length(URLends)]}; #pop URLends
od;
# Have found a ` ... is it the beginning of a `...' environment?
# It is if: it is not inside a URL, and
# ` is not followed by ` unless its followed by ``.
if IsEmpty(URLends) or p < URLends[1][1] then # not inside a URL
if p+1 < Length(lines[i]) and
lines[i]{[p+1..p+2]} in ["`'", "''"] then
# ``' or `'' (special cases: ` or ' inside `...')
p := p + 2; # skip over (nothing to do)
elif p = Length(lines[i]) or # ` (at end of line)
lines[i][p+1]<>'`' or # ` (on its own)
p+1 < Length(lines[i]) and lines[i][p+2]='`' # ```
then
verb := true;
break;
else # `` (but not ```) ... not a `...' environment
p := p + 1; # continue searching after second `
fi;
fi;
od;
if not verb then # ... or equivalently: if p = fail
break;
fi;
q := Position(lines[i],''',p);
while q<>fail and q<Length(lines[i]) and lines[i][q+1]=''' do
q := Position(lines[i],''',q+1);
od;
if q=fail then
q := Length(lines[i]);
else
verb := false; # changed for when we finish this pass of the loop
fi;
tail := lines[i]{[q+1..Length(lines[i])]};
line := Concatenation(lines[i]{[1..p]},
ReplacedString(lines[i]{[p+1..q]},"~","\\tilde"));
lines[i] := Concatenation(line,tail);
q := Length(line);
od;
# at this point any ~ that should not be changed to a blank has been
# temporarily replaced by: \tilde
lines[i] := ReplacedString( lines[i], "~", " " );
lines[i] := ReplacedString( lines[i], "\\tilde", "~" );
od;
EmptyLine();
return rec(lines := lines, start := start);
end);
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