post queries: support single-quoted strings in metatags.

app/logical/post_query/ast.rb

@@ -358,7 +358,7 @@ class PostQuery
       def quoted_value
         return nil unless metatag?
 
-        if value.include?(" ") || value.starts_with?('"') || value.empty?
+        if value.include?(" ") || value.starts_with?('"') || value.starts_with?("'") || value.empty?
           %Q{"#{value.gsub(/"/, '\\"')}"}
         else
           value

app/logical/post_query/parser.rb

@@ -24,6 +24,7 @@ require "strscan"
 # metatag       = metatag_name ":" quoted_string
 # metatag_name  = "user" | "fav" | "pool" | "order" | ...
 # quoted_string = '"' /[^"]+/ '"'
+#               | "'" /[^']+/ "'"
 # tag           = /[^ *]+/
 # wildcard      = /[^ ]+/
 #
@@ -172,6 +173,10 @@ class PostQuery
           a = accept(/([^"\\]|\\")*/).gsub(/\\"/, '"') # handle backslash escaped quotes
           expect('"')
           a
+        elsif accept("'")
+          a = accept(/([^'\\]|\\')*/).gsub(/\\'/, "'") # handle backslash escaped quotes
+          expect("'")
+          a
         else
           string(/[^ ]+/)
         end

test/unit/post_query_parser_test.rb

@@ -70,6 +70,13 @@ class PostQueryParserTest < ActiveSupport::TestCase
       assert_parse_equals('source:"\""', 'source:"\""')
       assert_parse_equals(%q{source:"don't say \"lazy\" okay"}, %q{source:"don't say \"lazy\" okay"})
       assert_parse_equals(%q{(and source:foo)bar a)}, %q{(a (source:"foo)bar"))})
+
+      assert_parse_equals('source:"foo bar"', "source:'foo bar'")
+      assert_parse_equals("source:foobar'(", "source:foobar'(")
+      assert_parse_equals('source:""', "source:''")
+      assert_parse_equals('source:"\'"', "source:'\\''")
+      assert_parse_equals(%q{source:"don't say \"lazy\" okay"}, %q{source:'don\'t say "lazy" okay'})
+      assert_parse_equals(%q{(and source:foo)bar a)}, %q{(a (source:'foo)bar'))})
     end
 
     should "parse wildcard tags correctly" do