############################################################################
#	File:     detex.icn
#	Subject:  Program to strip LaTeX commands
#	Author:   Clinton L. Jeffery
#	Date:     September 8, 1990
###########################################################################
#     Program that reads in documents written in the LaTeX typesetting
#  language, and removes some of the common LaTeX commands to produce
#  plain ASCII.  This program is not a full LaTeX parser, and output must
#  typically be further edited by hand to produce an acceptable result.
global fin, fout, silent, date, bibliography
procedure main(args)
    local cut, i, j
    initialize()
    cut := ""
    if *args=0 then {
	every write(\ (detex(!&input)))
    } else {
	i := 1
	while (args[i][1] == "-") do {
	    case args[i] of {
		"-silent": silent := 1
		"-cut"   : cut := "-cut"
		default  : write(&errout,"dont know option ",args[i])
	    }
	    i +:= 1
	if /silent then write(&errout,"Detex version 1.10 executed on ",date)
	if j := find(".tex",args[i]) then args[i][j:0] := ""
	fin := open(args[i]||".tex","r") |
	    stop("detex: couldn't open ",args[i],".tex for reading")
	fout := open(args[i]||".doc","w") |
	    stop("detex: couldn't open ",args[i],".doc for writing")
	every write(fout,\ (detex(!fin)))
	close(fin)
	if \bibliography then {
	    fin := open(bibliography,"r") |
		write(&errout,"detex: couldn't open ",
		      bibliography," for reading")
	    every write(fout,\ (debib(detex(!fin))))
	close(fout)
    }
procedure initialize()
    date := &dateline[find(",",&dateline)+2:0]
    date := reverse(date)
    date := date[find(":",date)+1:0]
    date := date[many(&digits,date):0]
    date := reverse(date)
# strip comments.  so far we only strip entire-line comments
procedure detex(s)
    if *s>0 & s[1]=="%" then fail
    return defootnote(deline(debrace(demacro(s))))
# remove footnotes and similar multiline entities
# all footnotes are assumed to end in }. and this is processed after
# all single-line entities were already processed
procedure defootnote(s)
    if s == "}" then return ""
    while s[find("\\footnote{",s) +: *"\\footnote{"] := " ("
    while s[find("}.",s) +: *"}."] := ")."
    return s
# This routine handles macros that may appear anywhere on a line
# Footnotes are translated into parentheses.
# The close of all footnotes are assumed to be }.
procedure demacro(s)
    local i
    while i := find("\\today",s) do {
	s[i:i+*"\\today"] := date
    }
    while i := find("\\cite{",s) do {
	s[i:i+*"\\cite{"] := "["
	s[find("}",s,i)] := "]"
    }
    while s[find("\\linebreak",s) +: *"\\linebreak"] := ""
    while s[find("\\/"|"\\\\"|"\\>",s) +: 2] := ""
    while s[find("``"|"''",s) +: 2] := "\""
    while s[ find("\\&"|"\\$"|"\\_",s) ] := ""
    return s
# extra help for .bbl files
procedure debib(s)
    local i
    while s[find("~",s)] := ""
    while (i:=find("{",s))=(find("}",s)-2) do s[i+:3] := s[i+1]
    while (i:=find("{",s))=(find("}",s)-3) do s[i+:4] := s[i+1]
    return s
# This procedure handles macros that comprise and entire line
procedure deline(s)
    local command, body
    if s[1] == "\\" then s ? {
	move(1)
	command := tab(many(&letters))
	case command of {
	    "item": {
		move(1) # past [
		body := tab(upto(']'))
		move(1)
		return body || tab(0)
	    }
	    "bibitem": {
		body := tab(upto(']')+1)
		return body
	    }
	    "newblock": {
		move(1)
		body := tab(0)
		return body
	    }
	    "bibliography": {
		tab(upto('{')+1)
		if not (body := tab(upto('}'))) then body := tab(0)
		bibliography := body || ".bbl"
		return trim(center("References",70))
	    }
	    "title" | "author" | "date" | "section" | "subsection" |
		"subsubsection": {
		    tab(upto('{')+1) # handle both \section{ and \section*{
		    if not (body := tab(upto('}'))) then body := tab(0)
		    return trim(center(body,70))
	    default: return ""
    } else
	return s
# This procedure removes braces which get inserted by common single-line
# environments such as font changes
procedure debrace(s)
    local i, j
    s ||:= " "
    while i := find("{\\em "|"{\\tt ",s) do {
	j := &null
	every j := bal(&cset,'{','}',s,i,0) \ 2
	if \j then {
            s := s[1:i] || s[i+5:j-1] || s[j:0]
    }
    return trim(s)