From 2dd148539d94cf582fafa03c77ef4f5c1ef5a045 Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Sun, 5 Oct 2014 09:32:21 +0200
Subject: [PATCH] Parsing of CSS predicates.

This adds support for parsing expressions such as "foo[class]".
---
 lib/oga/css/parser.y                   |  7 ++++++-
 spec/oga/css/parser/predicates_spec.rb | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 spec/oga/css/parser/predicates_spec.rb

diff --git a/lib/oga/css/parser.y b/lib/oga/css/parser.y
index 29a40cf..2db64bd 100644
--- a/lib/oga/css/parser.y
+++ b/lib/oga/css/parser.y
@@ -30,7 +30,8 @@ rule
     ;
 
   node_test
-    : node_name { s(:test, *val[0]) }
+    : node_name           { s(:test, *val[0]) }
+    | node_name predicate { s(:test, *val[0], val[1]) }
     ;
 
   node_name
@@ -43,6 +44,10 @@ rule
     # |foo
     | T_PIPE T_IDENT { [nil, val[1]] }
     ;
+
+  predicate
+    : T_LBRACK expression T_RBRACK { val[1] }
+    ;
 end
 
 ---- inner
diff --git a/spec/oga/css/parser/predicates_spec.rb b/spec/oga/css/parser/predicates_spec.rb
new file mode 100644
index 0000000..fa01c97
--- /dev/null
+++ b/spec/oga/css/parser/predicates_spec.rb
@@ -0,0 +1,17 @@
+require 'spec_helper'
+
+describe Oga::CSS::Parser do
+  context 'predicates' do
+    example 'parse a predicate' do
+      parse_css('foo[bar]').should == s(:test, nil, 'foo', s(:test, nil, 'bar'))
+    end
+
+    example 'parse a node test followed by a node test with a predicate' do
+      parse_css('foo bar[baz]').should == s(
+        :path,
+        s(:test, nil, 'foo'),
+        s(:test, nil, 'bar', s(:test, nil, 'baz'))
+      )
+    end
+  end
+end