#!/usr/bin/perl

# Ugly perl script to convert the example source code from "The
# Computational Beauty of Nature" to man pages.
#
# Written by Gary William Flake
#
# Permission granted for any use.  Knock yourself out.
#
######################################################################

$cbn2man = "cbn2man";

######################################################################

# Returns the first location in a list of the occurance of a pattern.

sub first_loc {
  local($where);
  local($pat, *array) = ($_[0], $_[1]);
  undef $where;
  for ($[ .. $#array) {
    $where = $_, last if $array[$_] =~ /$pat/;
  }
  $where;
}

######################################################################

sub first_loc_from {
  local($where);
  local($pat, $beg, *array) = ($_[0], $_[1], $_[2]);
  undef $where;
  for ($beg .. $#array) {
    $where = $_, last if $array[$_] =~ /$pat/;
  }
  $where;
}

######################################################################

# Grab each option from the options list and pretty print

sub do_synopsis {
  local($optname, $opttype);

  print OUTFILE ".SH SYNOPSIS\n.PD 0\n.TP\n.B $prog\ ";
  print OUTFILE "\\fB-help\n.LP\n\\ \\ or\n.TP\n.B $prog\n\\fB";
  for(@opts) {
    $optname = $_;
    $optname =~ s/\s*\{\s*\"([^\"]*)\",\s*([^,]*).*/\1/g;
    chop($optname);
    $opttype = $_;
    $opttype =~ s/\s*\{\s*\"([^\"]*)\",\s*([^,]*).*/\2/g;
    chop($opttype);
    $opttype =~ s/OPT_INT/ \\fIinteger\\fP/g;
    $opttype =~ s/OPT_DOUBLE/ \\fIdouble\\fP/g;
    $opttype =~ s/OPT_STRING/ \\fIstring\\fP/g;
    $opttype =~ s/OPT_SWITCH//g;
    $opttype =~ s/OPT_OTHER/ \\fI\\.\\.\\.\\fP/g;
    print OUTFILE "[\\$optname","$opttype]\n";
  }
  print OUTFILE ".PD 1\n";
}

######################################################################

# Grab the help string in print it as a description

sub do_description {
  local($beg, $end, @help);

  $beg = &first_loc('char\s*help_string', *rest);
  $end = &first_loc_from('\";', $beg + 1, *rest);
  @help = @rest[$beg .. $end];
  $help[0] =~ s/\s*char\s*help_string[^\"]*\"(.*)/\1/g;
  $help[$#help] =~ s/([^\"]*)\".*/\1/g;
  for (@help) {
    s/\\$//g;
  }
  if($help[0] =~ /^\s*$/) {
    @help = @help[1 .. $#help];
  }
  if($help[$#help] =~ /^\s*$/) {
    @help = @help[0 .. $#help - 1];
  }
  print OUTFILE ".SH DESCRIPTION\n";
  print OUTFILE @help;
}

######################################################################

# Pretty-print out each option description seperately.

sub do_options {
  local($optname, $opttype, $opthelp);

  print OUTFILE ".SH OPTIONS\n";
  for (@opts) {
    $optname = $_;
    $optname =~ s/\s*\{\s*\"([^\"]*)\",\s*([^,]*).*/\1/g;
    chop($optname);

    $opttype = $_;
    $opttype =~ s/\s*\{\s*\"([^\"]*)\",\s*([^,]*).*/\2/g;
    chop($opttype);
    $opttype =~ s/OPT_INT/\\ \\fIinteger\\fP/g;
    $opttype =~ s/OPT_DOUBLE/\\ \\fIdouble\\fP/g;
    $opttype =~ s/OPT_STRING/\\ \\fIstring\\fP/g;
    $opttype =~ s/OPT_SWITCH//g;
    $opttype =~ s/OPT_OTHER/\\ \\fI\\.\\.\\.\\fP/g;
    
    $opthelp = $_; 
    $opthelp =~ s/\s*\{\s*\"[^\"]*\"[^\"]*\"([^\"]*)\".*/\1/g;

    print OUTFILE ".IP \\fB\\$optname","$opttype\n";
    print OUTFILE $opthelp;
  }
}

######################################################################

# Pretty-print any remaining section except NAME and NOTES.

sub do_sections {
  local($beg, $end, $skip);
  
  $skip = 0;
  for (@header) {
    if($skip == 1) {
      if(/^[A-Z][A-Z]*/) {
	$skip = 0;
      }
    }
    if(/^[A-Z][A-Z]*/) {
      if(/^NAME/ || /^NOTES/) {
	$skip = 1;
      }
      else {
	print OUTFILE ".SH $_";
      }
    }
    elsif ($skip == 0) {
      s/^  //g;
      print OUTFILE $_;
    }
  }
}

######################################################################

sub main {

  open(INFILE, "-");
  open(OUTFILE, ">-");
  
  @lines = <INFILE>;
  close(INFILE);

  # Get the first header comment and clean it up.
  $beg = &first_loc('^/\*', *lines);
  $end = &first_loc_from('^ \*/', $beg + 1, *lines);
  @header = @lines[$beg .. $end - 1];
  $header[0] =~ s/^\/\* //g;
  for (@header[1 .. $#header]) {
    s/^ \* //g;
  }
  
  # Get everything but the header;
  @rest = @lines[$end + 1 .. $#lines];

  # Get the program name and description.
  $beg = &first_loc('^NAME', *header);
  $progline = $header[$beg + 1];
  $progline =~ s/ *([^ ].*)/\1/g;
  $prog = $progline;
  $prog =~ s/([^ ]*) .*/\1/g;
  $bigprog = $prog;
  $bigprog =~ tr/[a-z]/[A-Z]/;
  $progline =~ s/-/\\-/g;
  chop($prog);
  chop($bigprog);

  # Isolate the command line options and strip preproccesor directives
  $beg = &first_loc('^\s*OPTION', *rest);
  $end = &first_loc_from('^\s*{\s*NULL,\s*OPT_NULL', $beg + 1, *rest);
  @opts = @rest[$beg + 1 .. $end - 1];
  for (@opts) {
    s/^\s*#.*//g;
  }
  # Now, join continuation strings. 
  chop @opts;
  $opts = join('', @opts);
  $opts =~ s/\"\s*\"//g;
  @opts = split(/\},/, $opts);
  for (@opts) {
    $_ = "$_\n";
  }

  print OUTFILE ".TH $bigprog 1\n";
  print OUTFILE ".SH NAME\n.PD 0\n.TP\n$progline.PD 1\n";

  &do_synopsis;
  &do_description;
  &do_options;
  &do_sections;

  close(OUTFILE);
}

######################################################################

# Is it obvious that I am a C programmer?

&main;
exit 0;

######################################################################