#!/usr/bin/perl

use Text::Vpp ;
use Getopt::Long ;

require 5.6.0;

sub usage
  {
    die "vpp [-var foo=bar] [-varFile] [-action] [-nocomment] [-comment]\n",
    "    [-prefix] [-suffix] [-substitute] [-ignorebs] [-output output_file]\n",
    "    input_file \n\n",

    "var       : specify input_file variable, must be like var_name=var_value\n",
    "varFile   : specify a filename containing a Perl hash in Data::Dumper format\n",
    "action    : set action char (default \@)\n",
    "nocomment : input_file has no comment, all lines are passed to out file\n",
    "comment   : specify comment char (default #)\n",
    "prefix    : specify prefix char (default \$)\n",
    "suffix    : specify suffix char (default none)\n",
    "substitute: specify a pair like /prefix/suffix/ for evaled substitution\n",
    "            (default twice the action char)\n",
    "ignorebs  : don't append lines ending with \\ \n",
    "output    : output file name (default stdout)\n" ;
  }

my $ret = GetOptions('var=s@' => \@vars,'varFile=s' => \$varFile, 'action=s' => \$action,
                     'nocomment!'=>\$nocomment, 'output=s' => \$foutName,
                     'comment=s' => \$comment, 'prefix=s' => \$prefix,
                     'suffix=s' => \$suffix, 'substitute=s' => \$substitute,
                     'ignorebs'=> \$ignore)
  or usage ;

my $finName = shift ;
die "No input file\n" unless defined $finName ;

my $fin = Text::Vpp-> new($finName) ;

if (defined @vars)
  { my %Vars;
    foreach (@vars)
      {
        $Vars{$1}= $2  if /(\w+)=(.*)/ ;
      }
      $fin->setVar(\%Vars) ;
  }
elsif (defined $varFile)
  { $fin->setVarFromFile($varFile); }

$fin->setActionChar($action) if defined $action ;
$fin->setCommentChar(undef) if defined $nocomment ;
$fin->setCommentChar($comment) if defined $comment ;
$fin->setPrefixChar($prefix) if defined $prefix ;
$fin->setSuffixChar($suffix) if defined $suffix ;
if ( defined $substitute )
  { my @LS = $substitute =~ /(\S)([^\1]+)\1([^\1]+)\1/;
    shift @LS;
    $fin->setSubstitute([@LS]);
  }
$fin->ignoreBackslash if defined $ignore;

my $res;
if ( defined $foutName )
  { $res = $fin -> substitute($foutName) ;
    die "Vpp error ",$fin->getErrors,"\n" unless $res ;
  }
else
  { $res = $fin -> substitute;
    die "Vpp error ",$fin->getErrors,"\n" unless $res ;
    print join("\n",@{$fin->getText}),"\n";
  }



=head1 NAME

vpp - versatile text pre-processor

=head1 SYNOPSIS

 vpp -var toto=1 file_in > file_out
  
 #same result
 vpp -var toto=1 -output file_out file_in

=head1 DESCRIPTION

vpp enables you to pre-process a file.

Note that vpp is not designed to replace the well known cpp. 

=head1 INPUT FILE SYNTAX

See L<Text::Vpp/"INPUT FILE SYNTAX">.

=head1 command options

=head2 -var var_name=value

Specify variables that are used in the input file. The argument of the option
must be written like var_name=var_value
Don't forget to escape shell sensitive characters.

=head2 -varFile FileName

Specify a file (name FileName) which holds an 'external' representation of
a hash as it is created by Perl's Data::Dumper module.
Example:
$People = { 'person' =E<gt> { 'nick' =E<gt> 'Larry',
                               'name' =E<gt> 'Larry Wall',
                               'address' =E<gt> {
                                   'street' =E<gt> 'nirwana',
                                   'city' =E<gt> 'Perl.Org',
                                   'zip' =E<gt> '007'
                               }
                             },
            'pumpkin' =E<gt> { 'nick' =E<gt> 'Guru',
                               'name' =E<gt> 'Sarathy Gurusamy',
                               'address' =E<gt> {
                                   'state' =E<gt> 'Madison',
                                   'zip' =E<gt> '008'
                               }
                             }
          };

=head2 -action 'char'

Enables the user to use different char as action char. (default @)
Don't forget to escape shell sensitive characters.

Example: -action '#' will enable vpp to understand #include, #ifdef ..

=head2 -comment 'char'

Enables the user to use different char as comment char. (default #)
Don't forget to escape shell sensitive characters.

=head2 -nocomment

no comments are possible.

=head2 -prefix 'char'

Enables the user to use different char(s) as prefix char(s), i.e. variables
in your text (only) are prefixed by that character(s) instead of the
default '$'. If no suffix character(s) has been defined (or set to 'undef')
variables may be specified in the form ${variable} where '$' is the
current prefix char(s). This form is necessary, if any character which
is allowed within a name (regexp '\w') immediately follows the variable.
Note, that all variables in 'actions' (like @@ @EVAL @FOREACH @IF)
must still be prefixed by '$'.
Don't forget to escape shell sensitive characters.

=head2 -suffix 'char'

Enables the user to use different char(s) as suffix char(s), i.e. variables
in your text (only) are suffixed by that character(s).
Note, that all variables in 'actions' (like @@ @EVAL @FOREACH @IF)
don't use this.
Don't forget to escape shell sensitive characters.

=head2 -substitute /prefix/suffix/

Enables the user to specify the prefix and suffix used to mark
a Perl expression within the text that will be replaced by its
value. The default value is twice the 'action' char as suffix
and prefix. Instead of '/' any other non space character
can be used.
Don't forget to escape shell sensitive characters.


=head2 -ignorebs

By default, line ending with '\' are glued to the following line (like in
ksh). Once this method is called '\' will be left as is.

=head2 -output

 Specify the output file name, defaults to STDOUT
 You may prefix the filename with >> to get the output
 appended to an existing file.


=head1 AUTHOR

Dominique Dumont    Dominique_Dumont@grenoble.hp.com

Copyright (c) 1996-2001 Dominique Dumont. All rights reserved.  This
program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=head1 SEE ALSO

L<perl>, L<Text::Vpp>

=cut