From 636dbb830883090f23a566d7fa82024429a937ab Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Wed, 26 Sep 2012 17:52:53 -0500
Subject: sketch out the preprocessor

---
 lib/Text/Xslate/Syntax/Handlebars.pm | 134 +++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

(limited to 'lib')

diff --git a/lib/Text/Xslate/Syntax/Handlebars.pm b/lib/Text/Xslate/Syntax/Handlebars.pm
index e69de29..2d8f79d 100644
--- a/lib/Text/Xslate/Syntax/Handlebars.pm
+++ b/lib/Text/Xslate/Syntax/Handlebars.pm
@@ -0,0 +1,134 @@
+package Text::Xslate::Syntax::Handlebars;
+use Any::Moose;
+
+use Carp 'confess';
+use Text::Xslate::Util qw($STRING neat p);
+
+extends 'Text::Xslate::Syntax';
+
+sub _build_identity_pattern { qr/[A-Za-z_][A-Za-z0-9_]*/ }
+sub _build_comment_pattern  { qr/\![^;]*/                }
+
+sub _build_line_start { undef }
+sub _build_tag_start  { '{{'  } # XXX needs to be modifiable
+sub _build_tag_end    { '}}'  } # XXX needs to be modifiable
+
+sub _build_shortcut_table { +{} }
+
+sub split_tags {
+    my $self = shift;
+    my ($input) = @_;
+
+    my $tag_start = $self->tag_start;
+    my $tag_end   = $self->tag_end;
+
+    # 'text' is a something without newlines
+    # follwoing a newline, $tag_start, or end of the input
+    my $lex_text = qr/\A ( [^\n]*? (?: \n | (?= \Q$tag_start\E ) | \z ) ) /xms;
+
+    my $lex_comment = $parser->comment_pattern;
+    my $lex_code    = qr/(?: $lex_comment | (?: $STRING | [^'"] ) )/xms;
+
+    my @chunks;
+
+    my $close_tag;
+    while ($input) {
+        if ($close_tag) {
+            my $start = 0;
+            my $pos;
+            while(($pos = index $input, $close_tag, $start) >= 0) {
+                my $code = substr $input, 0, $pos;
+                $code =~ s/$lex_code//g;
+                if(length($code) == 0) {
+                    last;
+                }
+                $start = $pos + 1;
+            }
+
+            if ($pos >= 0) {
+                my $code = substr $_, 0, $pos, '';
+                $input =~ s/\A\Q$tag_end//
+                    or die "Oops!";
+
+                push @chunks, [
+                    ($close_tag eq '}}}' ? 'raw_code' : 'code'),
+                    $code
+                ];
+
+                undef $close_tag;
+            }
+            else {
+                last; # the end tag is not found
+            }
+        }
+        elsif ($input =~ s/\A\Q$tag_start//) {
+            if ($tag_start eq '{{' && $input =~ s/\A\{//) {
+                $close_tag = '}}}';
+            }
+            else {
+                $close_tag = $tag_end;
+            }
+        }
+        elsif ($input =~ s/\A$lex_text//) {
+            push @chunks, [ text => $1 ];
+        }
+        else {
+            confess "Oops: unreached code, near " . p($input);
+        }
+    }
+
+    if ($close_tag) {
+        # calculate line number
+        my $orig_src = $_[0];
+        substr $orig_src, -length($input), length($input), '';
+        my $line = ($orig_src =~ tr/\n/\n/);
+        $self->_error("Malformed templates detected",
+            neat((split /\n/, $input)[0]), ++$line,
+        );
+    }
+
+    return @chunks;
+}
+
+sub preprocess {
+    my $self = shift;
+    my ($input) = @_;
+
+    my @chunks = $self->split_tags($input);
+
+    my $code = '';
+    for my $chunk (@chunks) {
+        my ($type, $content) = @$chunk;
+        if ($type eq 'text') {
+            $content =~ s/(["\\])/\\$1/g;
+            $code .= qq{print_raw "$content";\n};
+        }
+        elsif ($type eq 'code') {
+            $code .= qq{$content;\n};
+        }
+        elsif ($type eq 'raw_code') {
+            $code .= qq{& $content;\n};
+        }
+        else {
+            $parser->_error("Oops: Unknown token: $s ($type)");
+        }
+    }
+
+    return $code;
+}
+
+sub tokenize {
+}
+
+# XXX advance has some syntax special cases in it, probably need to override
+# it too eventually
+# sub advance {
+# }
+
+sub init_symbols {
+}
+
+__PACKAGE__->meta->make_immutable;
+no Any::Moose;
+
+1;
-- 
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