From: Peter Rabbitson <ribasushi@cpan.org>
Date: Thu, 21 Oct 2010 13:36:51 +0000 (+0000)
Subject: Proper placeholder support in the AST
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=4e914a7c1dd88467a0d287073c9a9db477725394;p=scpubgit%2FQ-Branch.git

Proper placeholder support in the AST
---

diff --git a/lib/SQL/Abstract/Test.pm b/lib/SQL/Abstract/Test.pm
index 42491f9..4c28b5f 100644
--- a/lib/SQL/Abstract/Test.pm
+++ b/lib/SQL/Abstract/Test.pm
@@ -235,9 +235,13 @@ sub _parenthesis_unroll {
         $changes++;
       }
 
-      # only *ONE* LITERAL element
+      # only *ONE* LITERAL or placeholder element
       elsif (
-        @{$child->[1]} == 1 && $child->[1][0][0] eq 'LITERAL'
+        @{$child->[1]} == 1 && (
+          $child->[1][0][0] eq 'LITERAL'
+            or
+          $child->[1][0][0] eq 'PLACEHOLDER'
+        )
       ) {
         push @children, $child->[1][0];
         $changes++;
@@ -272,7 +276,8 @@ sub _parenthesis_unroll {
       # mathop, and our content is:
       # a single non-mathop child with a single PAREN grandchild which
       # would indicate mathop ( nonmathop ( ... ) )
-      # or a single non-mathop with a single LITERAL ( nonmathop ? )
+      # or a single non-mathop with a single LITERAL ( nonmathop foo )
+      # or a single non-mathop with a single PLACEHOLDER ( nonmathop ? )
       elsif (
         @{$child->[1]} == 1
           and
@@ -284,8 +289,10 @@ sub _parenthesis_unroll {
           and
         (
           $child->[1][0][1][0][0] eq 'PAREN'
-            or 
+            or
           $child->[1][0][1][0][0] eq 'LITERAL'
+            or
+          $child->[1][0][1][0][0] eq 'PLACEHOLDER'
         )
       ) {
         push @children, $child->[1][0];
diff --git a/lib/SQL/Abstract/Tree.pm b/lib/SQL/Abstract/Tree.pm
index 8d8449f..fd9f665 100644
--- a/lib/SQL/Abstract/Tree.pm
+++ b/lib/SQL/Abstract/Tree.pm
@@ -40,6 +40,8 @@ my $op_look_behind = '(?: (?<= [\,\s\)\(] ) | \A )';
 my $quote_left = qr/[\`\'\"\[]/;
 my $quote_right = qr/[\`\'\"\]]/;
 
+my $placeholder_re = qr/(?: \? | \$\d+ )/x;
+
 # These SQL keywords always signal end of the current expression (except inside
 # of a parenthesized subexpression).
 # Format: A list of strings that will be compiled to extended syntax ie.
@@ -114,6 +116,7 @@ my $all_known_re = join("\n\t|\n",
   $binary_op_re,
   "$op_look_behind (?i: AND|OR|NOT ) $op_look_ahead",
   (map { quotemeta $_ } qw/, ( ) */),
+  $placeholder_re,
 );
 
 $all_known_re = qr/$all_known_re/x;
@@ -131,7 +134,7 @@ use constant PARSE_RHS => 4;
 
 my $expr_term_re = qr/ ^ (?: $expr_start_re | \) ) $/x;
 my $rhs_term_re = qr/ ^ (?: $expr_term_re | $binary_op_re | (?i: AND | OR | NOT | \, ) ) $/x;
-my $func_start_re = qr/^ (?: \? | \$\d+ | \( ) $/x;
+my $func_start_re = qr/^ (?: \* | $placeholder_re | \( ) $/x;
 
 my %indents = (
    select        => 0,
@@ -326,6 +329,10 @@ sub _recurse_parse {
                     : [ $op => [$right] ];
 
     }
+    elsif ( $token =~ $placeholder_re) {
+      $left = $left ? [ $left, [ PLACEHOLDER => [ $token ] ] ]
+                    : [ PLACEHOLDER => [ $token ] ];
+    }
     # we're now in "unknown token" land - start eating tokens until
     # we see something familiar
     else {
@@ -421,11 +428,11 @@ sub _unparse {
     return join (' ', map $self->_unparse($_, $bindargs, $depth), @$tree);
   }
   elsif ($car eq 'LITERAL') {
-    if ($cdr->[0] eq '?') {
-      return $self->fill_in_placeholder($bindargs)
-    }
     return $cdr->[0];
   }
+  elsif ($car eq 'PLACEHOLDER') {
+    return $self->fill_in_placeholder($bindargs);
+  }
   elsif ($car eq 'PAREN') {
     return '(' .
       join(' ',