#!/usr/bin/perl

=head1 NAME

dh_python3-ply - generate versioned dependencies on python3-ply

=cut

use strict;
use warnings;

use Debian::Debhelper::Dh_Lib;

=head1 SYNOPSIS

B<dh_python3-ply> [B<--dependency-field> I<dependencyfield>] [S<I<debhelper options>>] I<file>...

=head1 DESCRIPTION

B<dh_python3-ply> is a debhelper program that is responsible for generating the
B<python3-ply:Depends> substitutions and adding them to substvars files.

The program will look only at Python3 modules that are explicitly provided as
its arguments, and will use this information to generate a strict versioned
dependency on B<python3-ply>.

=head1 OPTIONS

=over 4

=item B<--dependency-field> I<dependencyfield>

Use B<python3-ply:>I<dependencyfield> substitution variable instead of
B<python3-ply:Depends>.

=back

=cut

my $dependency_field = "Depends";

init(options => { "dependency-field:s" => \$dependency_field });

if (not @ARGV)
{
    error("at least one argument is required")
}

foreach my $filename (@ARGV)
{
    open FILE, $filename or error("cannot read $filename: $!");
    read FILE, $_, 1024;
    my $is_lextab = /^_lextokens\b/m;
    my $is_parsetab = /^_lr_method\b/m;
    $is_lextab or $is_parsetab or error("$filename doesn't look like a PLY table");
    (my $tabversion) = /^_tabversion\s*=\s*'([0-9.]+)'/m or error("$filename was generated by a very old PLY");
    my $dependency = sprintf "python3-ply-%s-%s", $is_lextab ? "lex" : "yacc", $tabversion;
    # Prefer real package names of "old" versions of PLY for easier upgrades from squeeze:
    if ($dependency eq "python3-ply-yacc-3.2")
    {
        # PLY 3.2, 3.3 and 3.4 embeds the same version number (3.2) in parser tables.
        $dependency = "python3-ply (>= 3.2), python3-ply (<< 3.5) | $dependency";
    }
    elsif ($dependency eq "python3-ply-lex-3.3")
    {
        # PLY 3.3 and 3.4 embeds their own version number in lexer tables.
        $dependency = "python3-ply (>= 3.3), python3-ply (<< 3.4) | $dependency";
    }
    foreach my $package (@{$dh{DOPACKAGES}})
    {
        addsubstvar($package, "python3-ply:$dependency_field", $dependency);
    }
}

=head1 SEE ALSO

L<debhelper(7)>

This program is not a part of debhelper, but it is meant to be used together with it.

=head1 AUTHOR

Jakub Wilk <jwilk@debian.org>

=cut

# vim:ts=4 sw=4 et