#! /usr/local/bin/perl
##---------------------------------------------------------------------------##
##  File:
##      @(#)  stripsgml 1.3 96/10/07 @(#)
##  Author:
##      Earl Hood       ehood@medusa.acs.uci.edu
##  Description:
##	Remove SGML markup.  Reads from STDIN, writes to STDOUT.
##	Character entities are converted to ASCII equivalents.  However,
##	due to the nature of some special characters, some special
##	characters may get lost in the output.
##
##  Usage:
##	% stripsgml [-html] < file.sgml > file.txt
##
##  	The -html option cause URLs in anchor elements in an HTML document
##	be preserved in the text output.
##
##---------------------------------------------------------------------------##
##  Copyright (C) 1994-1996  Earl Hood, ehood@medusa.acs.uci.edu
##
##  This program is free software; you can redistribute it and/or modify
##  it under the terms of the GNU General Public License as published by
##  the Free Software Foundation; either version 2 of the License, or
##  (at your option) any later version.
##
##  This program is distributed in the hope that it will be useful,
##  but WITHOUT ANY WARRANTY; without even the implied warranty of
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##  GNU General Public License for more details.
##
##  You should have received a copy of the GNU General Public License
##  along with this program; if not, write to the Free Software
##  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
##---------------------------------------------------------------------------##

package main;

##---------------------------------------------------------------------------##

($PROG = $0) =~ s/.*\///;
$VERSION = "1.0.0";

##---------------------------------------------------------------------------##
##	Require libraries
##---------------------------------------------------------------------------##
unshift(@INC, 'lib');
require "sgml.pl"	|| die "Unable to require sgml.pl\n";
require "newgetopt.pl"	|| die "Unable to require newgetopt.pl\n";

##---------------------------------------------------------------------------##
##	Associative array for entity substitutions
##---------------------------------------------------------------------------##

%Entity = (
#-----------------------------
# Numeric and Special Graphic
#-----------------------------
#   Entity      ASCII substitution
#   ----------  ------------------
    "half",	"1/2",	# fraction one-half
    "frac12",	"1/2",
    "#189",	"1/2",
    "frac14",	"1/4",	# fraction one-quarter
    "#188",	"1/4",
    "frac34",	"3/4",	# fraction three-quarters
    "#190",	"3/4",
    "frac18",	"1/8",	# fraction one-eighth
    "frac38",	"3/8",	# fraction three-eighths
    "frac58",	"5/8",	# fraction five-eighths
    "frac78",	"7/8",	# fraction seven-eighths
    "sup1",	"[1]",	# superscript one
    "#185",	"[1]",
    "sup2",	"[2]",	# superscript two
    "#178",	"[2]",
    "sup3",	"[3]",	# superscript three
    "#179",	"[3]",
    "plus",	"+",	# plus sign
    "plusmn",	"+/-",	# plus-or-minus sign
    "lt",	"<",	# less-than sign
    "equals",	"=",	# equals sign
    "gt",	">",	# greater-than sign
    "divide",	"/",	# divide sign
    "times",	"*",	# times sign
    "curren",	"\$",	# general currency sign
    "#164",	"\$",
    "pound",	"L",	# pound sign
    "#163",	"L",
    "dollar",	"\$",	# dollar sign
    "cent",	"c",	# cent sign
    "#162",	"c",
    "yen",	"Y",	# yen sign
    "#165",	"Y",
    "num",	"#",	# number sign
    "percent",	"%", 	# percent sign
    "amp",	"&",	# ampersand
    "ast",	"*",	# asterisk
    "commat",	"@",	# commercial at
    "lsqb",	"[",	# left square bracket
    "bsol",	"\\",	# reverse solidus
    "rsqb",	"]",	# right square bracket
    "lcub",	"{",	# left curly bracket
    "verbar",	"|",	# vertical bar
    "rcub",	"}",	# right curly bracket
    "copy",	"(C)",	# copyright sign
    "#169",	"(C)",
    "reg",	"(R)",	# registered sign
    "#174",	"(R)",
    "trade",	"(TM)",	# tradmark
    "brvbar",	"|",	# broken vertical bar
    "#166",	"|",
    "excl",	"!",	# exclamation mark
    "quot",	'"',	# quotation mark
    "apos",	"'",	# apostrophe
    "lpar",	"(",	# left parenthesis
    "rpar",	")",	# right parenthesis
    "comma",	",",	# comma
    "lowbar",	"_",	# low line
    "hyphen",	"-",	# hyphen
    "period",	".",	# full stop, period
    "sol",	"/",	# solidus
    "colon",	":",	# colon
    "semi",	";",	# semicolon
    "quest",	"?",	# question mark
    "laquo",	"<<",	# angle quotation mark, left
    "&#171",	"<<",
    "raquo",	">>",	# angle quotation mark, right
    "#187",	">>",
    "lsquo",	"'",	# single quotation mark, left
    "rsquo",	"'",	# single quotation mark, right
    "ldquo",	'"',	# double quotation mark, left
    "rdquo",	'"',	# double quotation mark, right
    "nbsp",	" ",	# no break (required) space
    "#160",	" ",
    "shy",	"-",	# soft hyphen
    "#173",	"-",

#---------------
# Added Latin 1
#---------------
#   Entity      ASCII substitution
#   ----------  ------------------
    "aacute",	"a",	# small a, acute accent
    "#225",	"a",
    "Aacute",	"A",	# capital A, acute accent
    "#193",	"A",
    "acirc",	"a",	# small a, circumflex accent
    "#226",	"a",
    "Acirc",	"A",	# capital A, circumflex accent
    "#194",	"A",
    "agrave",	"a",	# small a, grave accent
    "#224",	"a",
    "Agrave",	"A",	# capital A, grave accent
    "#192",	"A",
    "aring",	"a",	# small a, ring
    "#229",	"a",
    "Aring",	"A",	# capital A, ring
    "#197",	"A",
    "atilde",	"a",	# small a, tilde
    "#227",	"a",
    "Atilde",	"A",	# capital A, tilde
    "#195",	"A",
    "auml",	"a",	# small a, dieresis or umlaut mark
    "#228",	"a",
    "Auml",	"A",	# capital A, dieresis or umlaut mark
    "#196",	"A",
    "aelig",	"ae",	# small ae diphthong (ligature)
    "#230",	"ae",
    "AElig",	"AE",	# capital AE diphthong (ligature)
    "#198",	"AE",
    "ccedil",	"c",	# small c, cedilla
    "#231",	"c",
    "Ccedil",	"C",	# capital C, cedilla
    "#199",	"C",
    "eth",	"d",	# small eth, Icelandic
    "#240",	"d",
    "ETH",	"d",	# capital Eth, Icelandic
    "#208",	"d",
    "eacute",	"e",	# small e, acute accent
    "#233",	"e",
    "Eacute",	"E",	# capital E, acute accent
    "#201",	"E",
    "ecirc",	"e",	# small e, circumflex accent
    "#234",	"e",
    "Ecirc",	"E",	# capital E, circumflex accent
    "#202",	"E",
    "egrave",	"e",	# small e, grave accent
    "#232",	"e",
    "Egrave",	"E",	# capital E, grave accent
    "#200",	"E",
    "euml",	"e",	# small e, dieresis or umlaut mark
    "#235",	"e",
    "Euml",	"E",	# capital E, dieresis or umlaut mark
    "#203",	"E",
    "iacute",	"i",	# small i, acute accent
    "#237",	"i",
    "Iacute",	"I",	# capital I, acute accent
    "#205",	"I",
    "icirc",	"i",	# small i, circumflex accent
    "#238",	"i",
    "Icirc",	"I",	# capital I, circumflex accent
    "#206",	"I",
    "igrave",	"i",	# small i, grave accent
    "#236",	"i",
    "Igrave",	"I",	# capital I, grave accent
    "#204",	"I",
    "iuml",	"i",	# small i, dieresis or umlaut mark
    "#239",	"i",
    "Iuml",	"I",	# capital I, dieresis or umlaut mark
    "#207",	"I",
    "ntilde",	"n",	# small n, tilde
    "#241",	"n",
    "Ntilde",	"N",	# capital N, tilde
    "#209",	"N",
    "oacute",	"o",	# small o, acute accent
    "#243",	"o",
    "Oacute",	"O",	# capital O, acute accent
    "#211",	"O",
    "ocirc",	"o",	# small o, circumflex accent
    "#244",	"o",
    "Ocirc",	"O",	# capital O, circumflex accent
    "#212",	"O",
    "ograve",	"o",	# small o, grave accent
    "#242",	"o",
    "Ograve",	"O",	# capital O, grave accent
    "#210",	"O",
    "oslash",	"o",	# small o, slash
    "#248",	"o",
    "Oslash",	"O",	# capital O, slash
    "#216",	"O",
    "otilde",	"o",	# small o, tilde
    "#245",	"o",
    "Otilde",	"O",	# capital O, tilde
    "#213",	"O",
    "ouml",	"o",	# small o, dieresis or umlaut mark
    "#246",	"o",
    "Ouml",	"O",	# capital O, dieresis or umlaut mark
    "#214",	"O",
    "szlig",	"s",	# small sharp s, German (sz ligature)
    "#223",	"s",
    "thorn",	"p",	# small thorn, Icelandic
    "#254",	"p",
    "THORN",	"P",	# capital THORN, Icelandic
    "#222",	"P",
    "uacute",	"u",	# small u, acute accent
    "#250",	"u",
    "Uacute",	"U",	# capital U, acute accent
    "#218",	"U",
    "ucirc",	"u",	# small u, circumflex accent
    "#251",	"u",
    "Ucirc",	"U",	# capital U, circumflex accent
    "#219",	"U",
    "ugrave",	"u",	# small u, grave accent
    "#249",	"u",
    "Ugrave",	"U",	# capital U, grave accent
    "#217",	"U",
    "uuml",	"u",	# small u, dieresis or umlaut mark
    "#252",	"u",
    "Uuml",	"U",	# capital U, dieresis or umlaut mark
    "#220",	"U",
    "yacute",	"y",	# small y, acute accent
    "#253",	"y",
    "Yacute",	"Y",	# capital Y, acute accent
    "#221",	"Y",
    "yuml",	"y",	# small y, dieresis or umlaut mark
    "#255",	"y",
);

##---------------------------------------------------------------------------##
##	Globals
##---------------------------------------------------------------------------##

##	Variable to hold current URL
$Url	= '';

##	Register callbacks to sgml.pl
$sgml'CdataFunc		= "main'cdata_cb";
$sgml'OpenTagFunc	= "main'open_tag_cb";
$sgml'EndTagFunc	= "main'close_tag_cb";

##---------------------------------------------------------------------------##
				##------------##
				## Begin MAIN ##
				##------------##
{

&get_cli_opts();
&SGMLread_sgml(STDIN);
exit 0;

}
				##----------##
				## End MAIN ##
				##----------##
##---------------------------------------------------------------------------##
##	Routines
##---------------------------------------------------------------------------##

sub get_cli_opts {
    &Usage() unless
    &NGetOpt(
	"html",		# Generate compact listing

	"help"    	# Help message
    );
    &Usage()	if defined($opt_help);
    $HTML = 1	if defined($opt_html);
}

sub cdata_cb {
    local(*data) = shift;

    $data =~ s/\&([#\w-._]+);/&expand_ent($1)/ge;
    print STDOUT $data;
}

sub open_tag_cb {
    local($gi, $attr) = ($_[0], $_[1]);

    if ($HTML && ($gi =~ /^A$/i)) {
	if ($attr =~ /href\s*=\s*['"]([^'"]+)['"]/i) {
	    $Url = $1;
	    $Url = ''  if $Url =~ /^#/;		# Ignore relative URLs
	} else {
	    $Url = '';
	}
    }
}

sub close_tag_cb {
    local($gi) = ($_[0]);

    if ($HTML && ($gi =~ /^A$/i) && $Url) {
	print STDOUT " <URL:$Url>";
	$Url = '';
    }
}

sub expand_ent {
    local($name) = shift;
    defined($Entity{$name}) ? $Entity{$name} : "&$name;";
}

##---------------------------------------------------------------------------##
sub Usage {
    print STDOUT <<EndOfUsage;

Usage:  $PROG [<options>] <  file.sgm  > file.txt
Options:
  -html              : Preserve anchor URLs in output
  -help              : This message
 
Description:
  stripsgml strips out SGML tags.  Common entity references for special
  characters are converted to ASCII.  Input is read from standard in, and
  output is sent to standard out.
 
Version: $VERSION
dtd.pl Version: $dtd'VERSION
 
  Copyright (C) 1994-1996  Earl Hood, ehood\@medusa.acs.uci.edu
  stripsgml comes with ABSOLUTELY NO WARRANTY and stripsgml may be copied
  only under the terms of the GNU General Public License (version 2, or
  later), which may be found in the distribution.
EndOfUsage

    exit 0;
}