From 773419b9a00e36e0af08d0cb633b418ea60e1487 Mon Sep 17 00:00:00 2001
From: vi <me@vikramverma.com>
Date: Mon, 23 Jun 2014 14:39:19 +0800
Subject: [PATCH] Two simple combinators on Element: getAttr and hasAttr.

---
 src/Text/Taggy/Combinators.hs       | 11 +++++++++++
 tests/Text/Taggy/CombinatorsSpec.hs | 21 +++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 src/Text/Taggy/Combinators.hs
 create mode 100644 tests/Text/Taggy/CombinatorsSpec.hs

diff --git a/src/Text/Taggy/Combinators.hs b/src/Text/Taggy/Combinators.hs
new file mode 100644
index 0000000..9b13fe1
--- /dev/null
+++ b/src/Text/Taggy/Combinators.hs
@@ -0,0 +1,11 @@
+module Text.Taggy.Combinators (hasAttr, getAttr) where
+
+import Prelude hiding (lookup)
+import Text.Taggy.DOM (Element(..), AttrName, AttrValue)
+import Data.HashMap.Strict (lookup, keys)
+
+hasAttr :: Element -> AttrName -> Bool
+hasAttr = flip elem . keys . eltAttrs
+
+getAttr :: Element -> AttrName -> Maybe AttrValue
+getAttr = flip lookup . eltAttrs
diff --git a/tests/Text/Taggy/CombinatorsSpec.hs b/tests/Text/Taggy/CombinatorsSpec.hs
new file mode 100644
index 0000000..c714dc1
--- /dev/null
+++ b/tests/Text/Taggy/CombinatorsSpec.hs
@@ -0,0 +1,21 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Text.Taggy.CombinatorsSpec where
+
+import Text.Taggy.Combinators
+import Test.Hspec
+import Text.Taggy.DOM
+import Data.HashMap.Strict
+
+spec :: Spec
+spec = do
+  let element = Element "html" (fromList [("xmlns", "http://www.w3.org/1999/xhtml")]) []
+  describe "hasAttr" $ do
+    it "Tests whether an attribute is present." $ do
+      (element `hasAttr` "xmlns") `shouldBe` True
+      (element `hasAttr` "href") `shouldBe` False
+  describe "getAttr" $ do
+    it "Retrieves present attributes." $
+      (element `getAttr` "xmlns") `shouldBe` Just "http://www.w3.org/1999/xhtml"
+    it "Nothing's missing attributes." $ 
+      (element `getAttr` "style") `shouldBe` Nothing