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Current Path : /proc/self/root/usr/local/lib64/perl5/Template/Namespace/ |
Current File : //proc/self/root/usr/local/lib64/perl5/Template/Namespace/Constants.pm |
#================================================================= -*-Perl-*- # # Template::Namespace::Constants # # DESCRIPTION # Plugin compiler module for performing constant folding at compile time # on variables in a particular namespace. # # AUTHOR # Andy Wardley <abw@wardley.org> # # COPYRIGHT # Copyright (C) 1996-2022 Andy Wardley. All Rights Reserved. # # This module is free software; you can redistribute it and/or # modify it under the same terms as Perl itself. # #============================================================================ package Template::Namespace::Constants; use strict; use warnings; use base 'Template::Base'; use Template::Config; use Template::Directive; use Template::Exception; our $VERSION = '3.100'; our $DEBUG = 0 unless defined $DEBUG; sub _init { my ($self, $config) = @_; $self->{ STASH } = Template::Config->stash($config) || return $self->error(Template::Config->error()); return $self; } #------------------------------------------------------------------------ # ident(\@ident) foo.bar(baz) #------------------------------------------------------------------------ sub ident { my ($self, $ident) = @_; my @save = @$ident; # discard first node indicating constants namespace splice(@$ident, 0, 2); my $nelems = @$ident / 2; my ($e, $result); local $" = ', '; print STDERR "constant ident [ @$ident ] " if $DEBUG; foreach $e (0..$nelems-1) { # node name must be a constant unless ($ident->[$e * 2] =~ s/^'(.+)'$/$1/s) { $self->DEBUG(" * deferred (non-constant item: ", $ident->[$e * 2], ")\n") if $DEBUG; return Template::Directive->ident(\@save); } # if args is non-zero then it must be eval'ed if ($ident->[$e * 2 + 1]) { my $args = $ident->[$e * 2 + 1]; my $comp = eval "$args"; if ($@) { $self->DEBUG(" * deferred (non-constant args: $args)\n") if $DEBUG; return Template::Directive->ident(\@save); } $self->DEBUG("($args) ") if $comp && $DEBUG; $ident->[$e * 2 + 1] = $comp; } } $result = $self->{ STASH }->get($ident); if (! length $result || ref $result) { my $reason = length $result ? 'reference' : 'no result'; $self->DEBUG(" * deferred ($reason)\n") if $DEBUG; return Template::Directive->ident(\@save); } $result =~ s/'/\\'/g; $self->DEBUG(" * resolved => '$result'\n") if $DEBUG; return "'$result'"; } 1; __END__ =head1 NAME Template::Namespace::Constants - Compile time constant folding =head1 SYNOPSIS # easy way to define constants use Template; my $tt = Template->new({ CONSTANTS => { pi => 3.14, e => 2.718, }, }); # nitty-gritty, hands-dirty way use Template::Namespace::Constants; my $tt = Template->new({ NAMESPACE => { constants => Template::Namespace::Constants->new({ pi => 3.14, e => 2.718, }, }, }); =head1 DESCRIPTION The C<Template::Namespace::Constants> module implements a namespace handler which is plugged into the C<Template::Directive> compiler module. This then performs compile time constant folding of variables in a particular namespace. =head1 METHODS =head2 new(\%constants) The new() constructor method creates and returns a reference to a new Template::Namespace::Constants object. This creates an internal stash to store the constant variable definitions passed as arguments. my $handler = Template::Namespace::Constants->new({ pi => 3.14, e => 2.718, }); =head2 ident(\@ident) Method called to resolve a variable identifier into a compiled form. In this case, the method fetches the corresponding constant value from its internal stash and returns it. =head1 AUTHOR Andy Wardley E<lt>abw@wardley.orgE<gt> L<http://wardley.org/> =head1 COPYRIGHT Copyright (C) 1996-2022 Andy Wardley. All Rights Reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =head1 SEE ALSO L<Template::Directive> =cut # Local Variables: # mode: perl # perl-indent-level: 4 # indent-tabs-mode: nil # End: # # vim: expandtab shiftwidth=4: