From df2761aad16333724b3fe15635d4d99e1663f3c5 Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Sun, 16 Jun 2019 12:09:51 +1200
Subject: [PATCH] Compile 'complex' selectors (ones with multiple tests but no
 tree traversal).

I'm currently using a temporary datastructure which will be easily
replaced with curried functions later.
---
 src/Stylish/Element.hs         | 11 +++++++++++
 src/Stylish/Style/Interpret.hs | 30 ++++++++++++++++++++++++++++++
 test/Test.hs                   |  1 +
 3 files changed, 42 insertions(+)
 create mode 100644 src/Stylish/Element.hs
 create mode 100644 src/Stylish/Style/Interpret.hs

diff --git a/src/Stylish/Element.hs b/src/Stylish/Element.hs
new file mode 100644
index 0000000..97cee9c
--- /dev/null
+++ b/src/Stylish/Element.hs
@@ -0,0 +1,11 @@
+module Stylish.Element(
+        Element(..), Attribute(..)
+    ) where
+
+data Element = ElementNode {
+    parent :: Maybe Element,
+    previous :: Maybe Element,
+    name :: String,
+    attributes :: [Attribute] -- in sorted order.
+}
+data Attribute = Attribute String String
diff --git a/src/Stylish/Style/Interpret.hs b/src/Stylish/Style/Interpret.hs
new file mode 100644
index 0000000..417c897
--- /dev/null
+++ b/src/Stylish/Style/Interpret.hs
@@ -0,0 +1,30 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Stylish.Style.Interpret(
+        compile, SelectorFunc(..)
+    ) where
+
+import Stylish.Parse.Selector
+
+import Data.Text.Internal (Text(..))
+import Data.List
+
+data SelectorFunc = TestTag Text SelectorFunc | TestAttrs AttrsFunc SelectorFunc | Matched
+data AttrsFunc = TestAttr Text PropertyTest AttrsFunc | MatchedAttrs
+
+compile :: Selector -> SelectorFunc
+compile (Element selector) = compileInner selector
+
+compileInner selector = compileInner' $ lowerInner selector
+compileInner' (Just tag, attributes) = TestTag tag $ TestAttrs (compileAttrs $ sortAttrs attributes) Matched
+compileInner' (Nothing, attributes) = TestAttrs (compileAttrs $ sortAttrs attributes) Matched
+compileAttrs ((name, test):attrs) = TestAttr name test $ compileAttrs attrs
+compileAttrs [] = MatchedAttrs
+
+lowerInner :: [SimpleSelector] -> (Maybe Text, [(Text, PropertyTest)])
+lowerInner (Tag tag:selector) = (Just tag, snd $ lowerInner selector)
+lowerInner (Id id:s) = (tag, ("id", Include id):tail) where (tag, tail) = lowerInner s
+lowerInner (Class c:s) = (tag, ("class", Include c):tail) where (tag, tail) = lowerInner s
+lowerInner (Property name test:s) = (tag, (name, test):tail) where (tag, tail) = lowerInner s
+lowerInner [] = (Nothing, [])
+
+sortAttrs = sortBy compareAttrs where compareAttrs x y = fst x `compare` fst y
diff --git a/test/Test.hs b/test/Test.hs
index 788878a..e85d113 100644
--- a/test/Test.hs
+++ b/test/Test.hs
@@ -8,6 +8,7 @@ import Data.CSS.Syntax.Tokens
 import Stylish.Parse
 import Stylish.Style.Index
 import Stylish.Element
+import Stylish.Style.Interpret
 
 main = hspec spec
 
-- 
2.30.2