package t_template;

use strict;

use vars qw(@ISA @EXPORT_OK);

@ISA=();

@EXPORT_OK= qw(init setparm output);

sub init { # (\@parms, \%defaults, \@template)

    my ($self, $parms, $defs, $templatelines) = @_;

    $self->{parms} = { };

    $self->{values} = { };

    my $key;

    foreach $key (@$parms) {

	$self->{parms}{$key} = 1;

    }

    foreach $key (keys %$defs) {

	$self->{values}{$key} = ${$defs}{$key};

    }

    if (defined($templatelines)) {

	$self->{template} = join "", @$templatelines;

    }

}

sub validateparm { # (parmname)

    no strict 'refs';

    my ($self, $parmname) = @_;

    if (!defined($self->{parms}{$parmname})) {

	die "unknown parameter $parmname";

    }

}

sub setparm { # (parm, value)

    my ($self, $parm, $value) = @_;

    $self->validateparm($parm);

    $self->{values}{$parm} = $value;

}

sub substitute { # (text)

    my ($self, $text) = @_;

    my ($p);

    # Do substitutions.

    foreach $p (keys %{$self->{parms}}) {

	if (!defined $self->{values}{$p}) {

	    die "$0: No value supplied for parameter $p\n";

	}

	# XXX More careful quoting of supplied value!

	$text =~ s|<$p>|$self->{values}{$p}|g;

    }

    return $text;

}

sub output { # (fh)

    my ($self, $fh) = @_;

    print $fh "/* start of ", ref($self), " template */\n";

    print $fh $self->substitute($self->{template});

    print $fh "/* end of ", ref($self), " template */\n";

}

1;