Proper parsing support for all CSS operators.

lib/oga/css/parser.y

@@ -138,8 +138,76 @@ rule
     : node_name { s(:axis, 'attribute', s(:test, *val[0])) }
     ;
 
+  # The AST of these operators is mostly based on what
+  # `Nokogiri::CSS.xpath_for('...')` returns.
   operator
-    : attribute T_EQ string { s(:eq, val[0], val[2]) }
+    # a="b"
+    : attribute T_EQ string
+      {
+        s(:eq, val[0], val[2])
+      }
+
+    # a~="b"
+    | attribute T_SPACE_IN string
+      {
+        s(
+          :call,
+          'contains',
+          s(:call, 'concat', s(:string, ' '), val[0], s(:string, ' ')),
+          s(:call, 'concat', s(:string, ' '), val[2], s(:string, ' '))
+        )
+      }
+
+    # a^="b"
+    | attribute T_STARTS_WITH string
+      {
+        s(:call, 'starts-with', val[0], val[2])
+      }
+
+    # a$="b"
+    | attribute T_ENDS_WITH string
+      {
+        s(
+          :eq,
+          s(
+            :call,
+            'substring',
+            val[0],
+            s(
+              :add,
+              s(
+                :sub,
+                s(:call, 'string-length', val[0]),
+                s(:call, 'string-length', val[2])
+              ),
+              s(:int, 1)
+            ),
+            s(:call, 'string-length', val[2])
+          ),
+          val[2]
+        )
+      }
+
+    # a*="b"
+    | attribute T_IN string
+      {
+        s(:call, 'contains', val[0], val[2])
+      }
+
+    # a|="b"
+    | attribute T_HYPHEN_IN string
+      {
+        s(
+          :or,
+          s(:eq, val[0], val[2]),
+          s(
+            :call,
+            'starts-with',
+            val[0],
+            s(:call, 'concat', val[2], s(:string, '-'))
+          )
+        )
+      }
     ;
 
   class

spec/oga/css/parser/operators_spec.rb

@@ -3,56 +3,40 @@ require 'spec_helper'
 describe Oga::CSS::Parser do
   context 'operators' do
     example 'parse the = operator' do
-      parse_css('x[a="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:eq, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a="b"]').should == parse_xpath(
+        'descendant-or-self::x[@a="b"]'
       )
     end
 
     example 'parse the ~= operator' do
-      parse_css('x[a~="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:space_in, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a~="b"]').should == parse_xpath(
+        'descendant-or-self::x[contains(concat(" ", @a, " "), ' \
+          'concat(" ", "b", " "))]'
       )
     end
 
     example 'parse the ^= operator' do
-      parse_css('x[a^="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:starts_with, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a^="b"]').should == parse_xpath(
+        'descendant-or-self::x[starts-with(@a, "b")]'
       )
     end
 
     example 'parse the $= operator' do
-      parse_css('x[a$="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:ends_with, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a$="b"]').should == parse_xpath(
+        'descendant-or-self::x[substring(@a, string-length(@a) - ' \
+          'string-length("b") + 1, string-length("b")) = "b"]'
       )
     end
 
     example 'parse the *= operator' do
-      parse_css('x[a*="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:in, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a*="b"]').should == parse_xpath(
+        'descendant-or-self::x[contains(@a, "b")]'
       )
     end
 
     example 'parse the |= operator' do
-      parse_css('x[a|="b"]').should == s(
-        :test,
-        nil,
-        'x',
-        s(:hyphen_in, s(:test, nil, 'a'), s(:string, 'b'))
+      parse_css('x[a|="b"]').should == parse_xpath(
+        'descendant-or-self::x[@a = "b" or starts-with(@a, concat("b", "-"))]'
       )
     end
   end