#!/usr/bin/perl
# 
# Copyright © 2015-2025 by Vincent Slyngstad
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS LISTED ABOVE BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# 
# Except as contained in this notice, the names of the authors above
# shall not be used in advertising or otherwise to promote the sale, use
# or other dealings in this Software without prior written authorization
# from those authors.

# The PDP-8 help file has the following format:
#       <SP><CR><LF>
#       &COMMAND NAME
#       &ADDITIONAL COMMAND NAMES(IF ANY)
#       TEXT OF HELP INFO
#       &NEXT COMMAND NAME
#       TEXT OF NEXT HELP INFO
#       ETC.

$tools=`which $0`;
$tools =~ s:[^/]*$::; # basename

#
# Attempt to find a help file in the working directory.
# (Otherwise, use the one in 8tools.)
$open = 0;
for $i ("help.hl", "$tools/help.hl") {
  open(HELP, $i) || next;
  $open = 1;
  last;
}
die "No help file\n" unless $open;

#
# Inspect the argument. "*" and "help" list all the choices by searching for
# lines beginning with "&". Other values look for the corresponding "&" line,
# then dump text until a "\f" is found.
$help = 0;
push(@ARGV, 'ccl') unless @ARGV;
$help = 1 if $ARGV[0] =~ /^help/i;
$help = 1 if $ARGV[0] =~ /^[*]$/i;

if ($help) {
  #
  # List all help topics
  while (<HELP>) {
    next unless s/^&//;
    next if /^\r*$/;
    print;
  }
} else {
  $found = 0;
  while (<HELP>) {
    $found = 1 if /^[&]$ARGV[0]/i;
    last if $found;
  }
  die "No help for $ARGV[0]\n" unless $found;
  while (<HELP>) {
    s/^@//;
    next if /^[&]/;
    last if /^\f/;
    print;
  }
}