| 1 | # Movable Type (r) Open Source (C) 2001-2008 Six Apart, Ltd. |
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| 2 | # This program is distributed under the terms of the |
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| 3 | # GNU General Public License, version 2. |
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| 4 | # |
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| 5 | # $Id$ |
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| 6 | |
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| 7 | package MT::Builder; |
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| 8 | |
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| 9 | use strict; |
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| 10 | use base qw( MT::ErrorHandler ); |
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| 11 | |
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| 12 | use constant NODE => 'MT::Template::Node'; |
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| 13 | |
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| 14 | sub new { bless { }, $_[0] } |
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| 15 | |
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| 16 | sub compile { |
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| 17 | my $build = shift; |
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| 18 | my($ctx, $text, $opt) = @_; |
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| 19 | my $tmpl; |
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| 20 | |
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| 21 | $opt ||= { uncompiled => 1 }; |
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| 22 | my $depth = $opt->{depth} ||= 0; |
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| 23 | |
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| 24 | my $ids; |
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| 25 | my $classes; |
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| 26 | my $errors; |
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| 27 | |
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| 28 | # handle $builder->compile($template) signature |
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| 29 | if (UNIVERSAL::isa($ctx, 'MT::Template')) { |
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| 30 | $tmpl = $ctx; |
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| 31 | $ctx = $tmpl->context; |
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| 32 | $text = $tmpl->text; |
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| 33 | $tmpl->reset_tokens(); |
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| 34 | $ids = $build->{__state}{ids} = {}; |
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| 35 | $classes = $build->{__state}{classes} = {}; |
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| 36 | $errors = $build->{__state}{errors} = []; |
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| 37 | $build->{__state}{tmpl} = $tmpl; |
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| 38 | } else { |
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| 39 | $ids = $build->{__state}{ids} || {}; |
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| 40 | $classes = $build->{__state}{classes} || {}; |
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| 41 | $tmpl = $build->{__state}{tmpl}; |
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| 42 | $errors = $build->{__state}{errors} ||= []; |
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| 43 | } |
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| 44 | |
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| 45 | return [ ] unless defined $text; |
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| 46 | |
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| 47 | my $mods; |
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| 48 | |
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| 49 | # Translate any HTML::Template markup into native MT syntax. |
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| 50 | if ($text =~ m/<(?:MT_TRANS\b|MT_ACTION\b|(?:tmpl_(?:if|loop|unless|else|var|include)))/i) { |
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| 51 | translate_html_tmpl($text); |
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| 52 | } |
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| 53 | |
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| 54 | my $state = $build->{__state}; |
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| 55 | local $state->{tokens} = []; |
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| 56 | local $state->{classes} = $classes; |
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| 57 | local $state->{tmpl} = $tmpl; |
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| 58 | local $state->{ids} = $ids; |
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| 59 | local $state->{text} = \$text; |
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| 60 | |
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| 61 | my $pos = 0; |
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| 62 | my $len = length $text; |
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| 63 | # MT tag syntax: <MTFoo>, <$MTFoo$>, <$MTFoo> |
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| 64 | # <MT:Foo>, <$MT:Foo>, <$MT:Foo$> |
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| 65 | # <MTFoo:Bar>, <$MTFoo:Bar>, <$MTFoo:Bar$> |
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| 66 | # For 'function' tags, the '$' characters are optional |
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| 67 | # For namespace, the ':' is optional for the default 'MT' namespace. |
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| 68 | # Other namespaces (like 'Foo') would require the colon. |
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| 69 | # Tag and attributes are case-insensitive. So you can write: |
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| 70 | # <mtfoo>...</MTFOO> |
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| 71 | while ($text =~ m!(<\$?(MT:?)((?:<[^>]+?>|"[^"]*?"|'[^']*?'|.)+?)[\$/]?>)!gis) { |
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| 72 | my($whole_tag, $prefix, $tag) = ($1, $2, $3); |
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| 73 | ($tag, my($args)) = split /\s+/, $tag, 2; |
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| 74 | my $sec_start = pos $text; |
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| 75 | my $tag_start = $sec_start - length $whole_tag; |
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| 76 | _text_block($state, $pos, $tag_start) if $pos < $tag_start; |
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| 77 | $args ||= ''; |
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| 78 | # Structure of a node: |
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| 79 | # tag name, attribute hashref, contained tokens, template text, |
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| 80 | # attributes arrayref, parent array reference |
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| 81 | my $rec = bless [ $tag, \my %args, undef, undef, \my @args ], NODE; |
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| 82 | while ($args =~ / |
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| 83 | (?: |
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| 84 | (?: |
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| 85 | (\w+) #1 |
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| 86 | \s*=\s* |
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| 87 | (?:(?: |
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| 88 | (["']) #2 |
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| 89 | ((?:<[^>]+?>|.)*?) #3 |
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| 90 | \2 |
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| 91 | ( #4 |
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| 92 | (?: |
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| 93 | [,:] |
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| 94 | (["']) #5 |
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| 95 | (?:(?:<[^>]+?>|.)*?) |
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| 96 | \5 |
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| 97 | )+ |
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| 98 | )? |
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| 99 | ) | |
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| 100 | (\S+)) #6 |
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| 101 | ) |
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| 102 | ) | |
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| 103 | (\w+) #7 |
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| 104 | /gsx) { |
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| 105 | if (defined $7) { |
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| 106 | # An unnamed attribute gets stored in the 'name' argument. |
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| 107 | $args{'name'} = $7; |
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| 108 | } else { |
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| 109 | my $attr = lc $1; |
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| 110 | my $value = defined $6 ? $6 : $3; |
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| 111 | my $extra = $4; |
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| 112 | if (defined $extra) { |
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| 113 | my @extra; |
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| 114 | push @extra, $2 while $extra =~ m/[,:](["'])((?:<[^>]+?>|.)*?)\1/gs; |
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| 115 | $value = [ $value, @extra ]; |
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| 116 | } |
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| 117 | # We need a reference to the filters to check |
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| 118 | # attributes and whether they need to be in the array of |
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| 119 | # attributes for post-processing. |
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| 120 | $mods ||= $ctx->{__filters}; |
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| 121 | push @args, [$attr, $value] if exists $mods->{$attr}; |
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| 122 | $args{$attr} = $value; |
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| 123 | if ($attr eq 'id') { |
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| 124 | # store a reference to this token based on the 'id' for it |
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| 125 | $ids->{$3} = $rec; |
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| 126 | } |
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| 127 | elsif ($attr eq 'class') { |
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| 128 | # store a reference to this token based on the 'id' for it |
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| 129 | $classes->{lc $3} ||= []; |
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| 130 | push @{ $classes->{lc $3} }, $rec; |
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| 131 | } |
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| 132 | } |
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| 133 | } |
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| 134 | my($h, $is_container) = $ctx->handler_for($tag); |
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| 135 | if (!$h) { |
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| 136 | # determine line # |
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| 137 | my $pre_error = substr($text, 0, $tag_start); |
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| 138 | my @m = $pre_error =~ m/\r?\n/g; |
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| 139 | my $line = scalar @m; |
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| 140 | if ($depth) { |
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| 141 | $opt->{error_line} = $line; |
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| 142 | push @$errors, { message => MT->translate("<[_1]> at line [_2] is unrecognized.", $prefix . $tag, "#"), line => $line }; |
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| 143 | } else { |
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| 144 | push @$errors, { message => MT->translate("<[_1]> at line [_2] is unrecognized.", $prefix . $tag, $line + 1), line => $line }; |
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| 145 | } |
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| 146 | } |
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| 147 | if ($is_container) { |
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| 148 | if ($whole_tag !~ m|/>$|) { |
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| 149 | my ($sec_end, $tag_end) = _consume_up_to(\$text,$sec_start,$tag); |
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| 150 | if ($sec_end) { |
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| 151 | my $sec = $tag =~ m/ignore/i ? '' # ignore MTIgnore blocks |
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| 152 | : substr $text, $sec_start, $sec_end - $sec_start; |
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| 153 | if ($sec !~ m/<\$?MT/i) { |
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| 154 | $rec->[2] = [ ($sec ne '' ? ['TEXT', $sec ] : ()) ]; |
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| 155 | } |
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| 156 | else { |
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| 157 | local $opt->{depth} = $opt->{depth} + 1; |
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| 158 | local $opt->{parent} = $rec; |
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| 159 | $rec->[2] = $build->compile($ctx, $sec, $opt); |
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| 160 | if ( @$errors ) { |
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| 161 | my $pre_error = substr($text, 0, $sec_start); |
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| 162 | my @m = $pre_error =~ m/\r?\n/g; |
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| 163 | my $line = scalar @m; |
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| 164 | foreach (@$errors) { |
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| 165 | $line += $_->{line}; |
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| 166 | $_->{line} = $line; |
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| 167 | $_->{message} =~ s/#/$line/; |
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| 168 | } |
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| 169 | } |
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| 170 | # unless (defined $rec->[2]) { |
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| 171 | # my $pre_error = substr($text, 0, $sec_start); |
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| 172 | # my @m = $pre_error =~ m/\r?\n/g; |
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| 173 | # my $line = scalar @m; |
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| 174 | # if ($depth) { |
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| 175 | # $opt->{error_line} = $line + ($opt->{error_line} || 0); |
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| 176 | # return; |
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| 177 | # } |
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| 178 | # else { |
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| 179 | # $line += ($opt->{error_line} || 0) + 1; |
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| 180 | # my $err = $build->errstr; |
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| 181 | # $err =~ s/#/$line/; |
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| 182 | # return $build->error($err); |
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| 183 | # } |
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| 184 | # } |
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| 185 | } |
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| 186 | $rec->[3] = $sec if $opt->{uncompiled}; |
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| 187 | } |
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| 188 | else { |
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| 189 | my $pre_error = substr($text, 0, $tag_start); |
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| 190 | my @m = $pre_error =~ m/\r?\n/g; |
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| 191 | my $line = scalar @m; |
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| 192 | if ($depth) { |
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| 193 | # $opt->{error_line} = $line; |
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| 194 | # return $build->error(MT->translate("<[_1]> with no </[_1]> on line #", $prefix . $tag)); |
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| 195 | push @$errors, { message => MT->translate("<[_1]> with no </[_1]> on line [_2].", $prefix . $tag, "#" ), line => $line }; |
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| 196 | } |
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| 197 | else { |
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| 198 | push @$errors, { message => MT->translate("<[_1]> with no </[_1]> on line [_2].", $prefix . $tag, $line +1 ), line => $line + 1 }; |
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| 199 | # return $build->error(MT->translate("<[_1]> with no </[_1]> on line [_2]", $prefix . $tag, $line + 1)); |
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| 200 | } |
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| 201 | last; # return undef; |
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| 202 | } |
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| 203 | $pos = $tag_end + 1; |
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| 204 | (pos $text) = $tag_end; |
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| 205 | } |
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| 206 | else { |
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| 207 | $rec->[3] = ''; |
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| 208 | } |
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| 209 | } |
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| 210 | $rec->[5] = $opt->{parent} || $tmpl; |
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| 211 | $rec->[6] = $tmpl; |
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| 212 | push @{ $state->{tokens} }, $rec; |
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| 213 | $pos = pos $text; |
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| 214 | } |
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| 215 | _text_block($state, $pos, $len) if $pos < $len; |
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| 216 | if (defined $tmpl) { |
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| 217 | # assign token and id references to template |
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| 218 | $tmpl->tokens($state->{tokens}); |
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| 219 | $tmpl->token_ids($state->{ids}); |
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| 220 | $tmpl->token_classes($state->{classes}); |
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| 221 | $tmpl->errors($state->{errors}) |
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| 222 | if $state->{errors} && (@{$state->{errors}}); |
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| 223 | } |
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| 224 | return $state->{tokens}; |
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| 225 | } |
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| 226 | |
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| 227 | sub translate_html_tmpl { |
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| 228 | $_[0] =~ s!<(/?)tmpl_(if|loop|unless|else|var|include)\b!<$1mt:$2!ig; |
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| 229 | $_[0] =~ s!<MT_TRANS\b!<__trans!ig; |
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| 230 | $_[0] =~ s!<MT_ACTION\b!<__action!ig; |
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| 231 | } |
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| 232 | |
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| 233 | sub _consume_up_to { |
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| 234 | my($text, $start, $stoptag) = @_; |
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| 235 | my $pos; |
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| 236 | (pos $$text) = $start; |
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| 237 | while ($$text =~ m!(<([\$/]?)MT:?($stoptag)\b(?:[^>]*?)[\$/]?>)!gi) { |
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| 238 | my($whole_tag, $prefix, $tag) = ($1, $2, $3); |
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| 239 | my $end = pos $$text; |
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| 240 | if ($prefix && ($prefix eq '/')) { |
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| 241 | return ($end - length($whole_tag), $end); |
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| 242 | } elsif ($whole_tag !~ m|/>|) { |
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| 243 | my ($sec_end, $end_tag) = _consume_up_to($text, $end, $tag); |
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| 244 | last if !$sec_end; |
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| 245 | (pos $$text) = $end_tag; |
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| 246 | } |
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| 247 | } |
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| 248 | # special case for unclosed 'else' tag: |
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| 249 | if (lc($stoptag) eq 'else' || lc($stoptag) eq 'elseif') { |
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| 250 | return ($start + length($$text), $start + length($$text)); |
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| 251 | } |
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| 252 | return (0, 0); |
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| 253 | } |
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| 254 | |
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| 255 | sub _text_block { |
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| 256 | my $text = substr ${ $_[0]->{text} }, $_[1], $_[2] - $_[1]; |
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| 257 | push @{ $_[0]->{tokens} }, bless [ 'TEXT', $text, undef, undef, undef, $_[0]->{tokens}, $_[0]->{tmpl} ], NODE |
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| 258 | if (defined $text) && ($text ne ''); |
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| 259 | } |
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| 260 | |
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| 261 | sub syntree2str { |
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| 262 | my ($tokens, $depth) = @_; |
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| 263 | my $string = ''; |
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| 264 | foreach my $t (@$tokens) { |
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| 265 | my ($name, $args, $tokens, $uncompiled) = @$t; |
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| 266 | $string .= (" " x $depth) . $name; |
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| 267 | if (ref $args eq 'HASH') { |
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| 268 | $string .= join(", ", (map { " $_ => " . $args->{$_} } |
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| 269 | (keys %$args))); |
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| 270 | } |
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| 271 | |
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| 272 | $string.= "\n"; |
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| 273 | $string .= syntree2str($tokens, $depth + 2); |
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| 274 | } |
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| 275 | return $string; |
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| 276 | } |
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| 277 | |
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| 278 | my $count=0; |
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| 279 | sub build { |
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| 280 | my $build = shift; |
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| 281 | my($ctx, $tokens, $cond) = @_; |
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| 282 | |
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| 283 | #print STDERR syntree2str($tokens,0) unless $count++ == 1; |
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| 284 | |
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| 285 | if ($cond) { |
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| 286 | my %lcond; |
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| 287 | # lowercase condtional keys since we're storing tags in lowercase now |
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| 288 | %lcond = map { lc $_ => $cond->{$_} } keys %$cond; |
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| 289 | $cond = \%lcond; |
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| 290 | } else { |
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| 291 | $cond = {}; |
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| 292 | } |
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| 293 | $ctx->stash('builder', $build); |
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| 294 | my $res = ''; |
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| 295 | my $ph = $ctx->post_process_handler; |
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| 296 | |
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| 297 | for my $t (@$tokens) { |
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| 298 | if ($t->[0] eq 'TEXT') { |
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| 299 | $res .= $t->[1]; |
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| 300 | } else { |
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| 301 | my($tokens, $tokens_else, $uncompiled); |
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| 302 | my $tag = lc $t->[0]; |
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| 303 | if ($cond && (exists $cond->{ $tag } && !$cond->{ $tag })) { |
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| 304 | # if there's a cond for this tag and it's false, |
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| 305 | # walk the children and look for an MTElse. |
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| 306 | # the children of the MTElse will become $tokens |
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| 307 | for my $tok (@{ $t->[2] }) { |
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| 308 | if (lc $tok->[0] eq 'else' || lc $tok->[0] eq 'elseif') { |
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| 309 | $tokens = $tok->[2]; |
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| 310 | $uncompiled = $tok->[3]; |
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| 311 | last; |
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| 312 | } |
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| 313 | } |
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| 314 | next unless $tokens; |
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| 315 | } else { |
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| 316 | if ($t->[2] && ref($t->[2])) { |
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| 317 | # either there is no cond for this tag, or it's true, |
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| 318 | # so we want to partition the children into |
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| 319 | # those which are inside an else and those which are not. |
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| 320 | ($tokens, $tokens_else) = ([], []); |
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| 321 | for my $sub (@{ $t->[2] }) { |
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| 322 | if (lc $sub->[0] eq 'else' || lc $sub->[0] eq 'elseif') { |
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| 323 | push @$tokens_else, $sub; |
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| 324 | } else { |
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| 325 | push @$tokens, $sub; |
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| 326 | } |
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| 327 | } |
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| 328 | } |
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| 329 | $uncompiled = $t->[3]; |
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| 330 | } |
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| 331 | my($h, $type) = $ctx->handler_for($t->[0]); |
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| 332 | if ($h) { |
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| 333 | my $start; |
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| 334 | if ($MT::DebugMode & 8) { |
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| 335 | require Time::HiRes; |
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| 336 | $start = [ Time::HiRes::gettimeofday() ]; |
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| 337 | } |
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| 338 | local($ctx->{__stash}{tag}) = $t->[0]; |
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| 339 | local($ctx->{__stash}{tokens}) = ref($tokens) ? bless $tokens, 'MT::Template::Tokens' : undef; |
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| 340 | local($ctx->{__stash}{tokens_else}) = ref($tokens_else) ? bless $tokens_else, 'MT::Template::Tokens' : undef; |
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| 341 | local($ctx->{__stash}{uncompiled}) = $uncompiled; |
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| 342 | my %args = %{$t->[1]} if defined $t->[1]; |
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| 343 | my @args = @{$t->[4]} if defined $t->[4]; |
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| 344 | |
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| 345 | # process variables |
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| 346 | foreach my $v (keys %args) { |
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| 347 | if (ref $args{$v} eq 'ARRAY') { |
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| 348 | foreach (@{$args{$v}}) { |
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| 349 | if (m/^\$([A-Za-z_](\w|\.)*)$/) { |
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| 350 | $_ = $ctx->var($1); |
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| 351 | } |
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| 352 | } |
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| 353 | } else { |
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| 354 | if ($args{$v} =~ m/^\$([A-Za-z_](\w|\.)*)$/) { |
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| 355 | $args{$v} = $ctx->var($1); |
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| 356 | } |
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| 357 | } |
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| 358 | } |
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| 359 | foreach (@args) { |
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| 360 | $_ = [ $_->[0], $_->[1] ]; |
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| 361 | my $arg = $_; |
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| 362 | if (ref $arg->[1] eq 'ARRAY') { |
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| 363 | $arg->[1] = [ @{$arg->[1]} ]; |
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| 364 | foreach (@{$arg->[1]}) { |
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| 365 | if (m/^\$([A-Za-z_](\w|\.)*)$/) { |
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| 366 | $_ = $ctx->var($1); |
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| 367 | } |
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| 368 | } |
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| 369 | } else { |
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| 370 | if ($arg->[1] =~ m/^\$([A-Za-z_](\w|\.)*)$/) { |
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| 371 | $arg->[1] = $ctx->var($1); |
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| 372 | } |
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| 373 | } |
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| 374 | } |
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| 375 | |
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| 376 | # Stores a reference to the ordered list of arguments, |
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| 377 | # just in case the handler wants them |
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| 378 | local $args{'@'} = \@args; |
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| 379 | my $out = $h->($ctx, \%args, $cond); |
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| 380 | |
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| 381 | unless (defined $out) { |
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| 382 | my $err = $ctx->errstr; |
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| 383 | if (defined $err) { |
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| 384 | return $build->error(MT->translate("Error in <mt:[_1]> tag: [_2]", $t->[0], $ctx->errstr)); |
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| 385 | } |
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| 386 | else { |
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| 387 | # no error was given, so undef will mean '' in |
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| 388 | # such a scenario |
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| 389 | $out = ''; |
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| 390 | } |
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| 391 | } |
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| 392 | |
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| 393 | if ((defined $type) && ($type == 2)) { |
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| 394 | # conditional; process result |
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| 395 | $out = $out ? $ctx->slurp(\%args, $cond) : $ctx->else(\%args, $cond); |
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| 396 | delete $ctx->{__stash}{vars}->{__value__}; |
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| 397 | delete $ctx->{__stash}{vars}->{__name__}; |
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| 398 | } |
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| 399 | |
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| 400 | $out = $ph->($ctx, \%args, $out, \@args) |
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| 401 | if %args && $ph; |
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| 402 | $res .= $out |
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| 403 | if defined $out; |
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| 404 | if ($MT::DebugMode & 8) { |
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| 405 | my $elapsed = Time::HiRes::tv_interval($start); |
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| 406 | print STDERR "Builder: Tag [" . $t->[0] . "] - $elapsed seconds\n" if $elapsed > 0.25; |
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| 407 | } |
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| 408 | } else { |
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| 409 | if ($t->[0] !~ m/^_/) { # placeholder tag. just ignore |
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| 410 | return $build->error(MT->translate("Unknown tag found: [_1]", $t->[0])); |
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| 411 | } |
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| 412 | } |
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| 413 | } |
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| 414 | } |
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| 415 | |
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| 416 | return $res; |
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| 417 | } |
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| 418 | |
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| 419 | 1; |
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| 420 | __END__ |
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| 421 | |
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| 422 | =head1 NAME |
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| 423 | |
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| 424 | MT::Builder - Parser and interpreter for MT templates |
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| 425 | |
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| 426 | =head1 SYNOPSIS |
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| 427 | |
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| 428 | use MT::Builder; |
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| 429 | use MT::Template::Context; |
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| 430 | |
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| 431 | my $build = MT::Builder->new; |
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| 432 | my $ctx = MT::Template::Context->new; |
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| 433 | |
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| 434 | my $tokens = $build->compile($ctx, '<$MTVersion$>') |
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| 435 | or die $build->errstr; |
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| 436 | defined(my $out = $build->build($ctx, $tokens)) |
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| 437 | or die $build->errstr; |
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| 438 | |
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| 439 | =head1 DESCRIPTION |
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| 440 | |
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| 441 | I<MT::Builder> provides the parser and interpreter for taking a template |
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| 442 | body and turning it into a generated output page. An I<MT::Builder> object |
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| 443 | knows how to parse a string of text into tokens, then take those tokens and |
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| 444 | build a scalar string representing the output of the page. It does not, |
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| 445 | however, know anything about the types of tags that it encounters; it hands |
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| 446 | off this work to the I<MT::Template::Context> object, which can look up a |
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| 447 | tag and determine whether it's valid, whether it's a container or substitution |
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| 448 | tag, etc. |
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| 449 | |
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| 450 | All I<MT::Builder> knows is the basic structure of a Movable Type tag, and |
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| 451 | how to break up a string into pieces: plain text pieces interspersed with |
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| 452 | tag callouts. It then knows how to take a list of these tokens/pieces and |
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| 453 | build a completed page, using the same I<MT::Template::Context> object to |
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| 454 | actually fill in the values for the Movable Type tags. |
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| 455 | |
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| 456 | =head1 USAGE |
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| 457 | |
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| 458 | =head2 MT::Builder->new |
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| 459 | |
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| 460 | Constructs and returns a new parser/interpreter object. |
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| 461 | |
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| 462 | =head2 $build->compile($ctx, $string) |
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| 463 | |
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| 464 | Given an I<MT::Template::Context> object I<$ctx>, breaks up the scalar string |
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| 465 | I<$string> into tokens and returns the list of tokens as a reference to an |
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| 466 | array. Returns C<undef> on compilation failure. |
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| 467 | |
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| 468 | =head2 $build->build($ctx, \@tokens [, \%cond ]) |
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| 469 | |
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| 470 | Given an I<MT::Template::Context> object I<$ctx>, turns a list of tokens |
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| 471 | I<\@tokens> and generates an output page. Returns the output page on success, |
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| 472 | C<undef> on failure. Note that the empty string (C<''>) and the number zero |
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| 473 | (C<0>) are both valid return values for this method, so you should check |
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| 474 | specifically for an undefined value when checking for errors. |
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| 475 | |
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| 476 | The optional argument I<\%cond> specifies a list of conditions under which |
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| 477 | the tokens will be interpreted. If provided, I<\%cond> should be a reference |
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| 478 | to a hash, where the keys are MT tag names (without the leading C<MT>), and |
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| 479 | the values are boolean flags specifying whether to include the tag; a true |
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| 480 | value means that the tag should be included in the final output, a false value |
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| 481 | that it should not. This is useful when a template includes conditional |
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| 482 | container tags (eg C<E<lt>MTEntryIfExtendedE<gt>>), and you wish to influence |
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| 483 | the inclusion of these container tags. For example, if a template contains |
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| 484 | the container |
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| 485 | |
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| 486 | <MTEntryIfExtended> |
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| 487 | <$MTEntryMore$> |
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| 488 | </MTEntryIfExtended> |
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| 489 | |
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| 490 | and you wish to exclude this conditional, you could call I<build> like this: |
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| 491 | |
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| 492 | my $out = $build->build($ctx, $tokens, { EntryIfExtended => 0 }); |
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| 493 | |
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| 494 | =head2 $build->syntree2str(\@tokens) |
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| 495 | |
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| 496 | Internal debugging routine to dump a set of template tokens. Returns a |
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| 497 | readable string of contents of the C<$tokens> parameter. |
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| 498 | |
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| 499 | =head1 ERROR HANDLING |
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| 500 | |
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| 501 | On an error, the above methods return C<undef>, and the error message can |
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| 502 | be obtained by calling the method I<errstr> on the object. For example: |
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| 503 | |
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| 504 | defined(my $out = $build->build($ctx, $tokens)) |
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| 505 | or die $build->errstr; |
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| 506 | |
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| 507 | =head1 AUTHOR & COPYRIGHTS |
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| 508 | |
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| 509 | Please see the I<MT> manpage for author, copyright, and license information. |
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| 510 | |
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| 511 | =cut |
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