Support attributes in HTML paths in style mappings

4 files changed, 60 insertions, 12 deletions

diff --git a/NEWS b/NEWS
index 9fc29b3..70baaf5 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,7 @@
+# 1.7.0
+
+* Support attributes in HTML paths in style mappings.
+
 # 1.6.0
 
 * Add transformDocument to the TypeScript declarations.
diff --git a/README.md b/README.md
index b167336..7144c72 100644
--- a/README.md
+++ b/README.md
@@ -805,6 +805,12 @@ append a dot followed by the name of the class:
 h1.section-title
 ```
 
+To add an attribute, use square brackets similarly to a CSS attribute selector:
+
+```
+p[lang="fr"]
+```
+
 To require that an element is fresh, use `:fresh`:
 
 ```
diff --git a/lib/style-reader.js b/lib/style-reader.js
index 07521ad..38202f9 100644
--- a/lib/style-reader.js
+++ b/lib/style-reader.js
@@ -57,12 +57,13 @@ function documentMatcherRule() {
         runRule
     );
 
-    var styleIdRule = lop.rules.then(
-        classRule,
-        function(styleId) {
-            return {styleId: styleId};
-        }
-    );
+    var styleIdRule = lop.rules.sequence(
+        lop.rules.tokenOfType("dot"),
+        lop.rules.sequence.cut(),
+        lop.rules.sequence.capture(identifierRule)
+    ).map(function(styleId) {
+        return {styleId: styleId};
+    });
 
     var styleNameMatcherRule = lop.rules.firstOf("style name matcher",
         lop.rules.then(
@@ -234,15 +235,19 @@ function htmlPathRule() {
 
     var styleElementRule = lop.rules.sequence(
         capture(tagNamesRule),
-        capture(lop.rules.zeroOrMore(classRule)),
+        capture(lop.rules.zeroOrMore(attributeOrClassRule)),
         capture(freshRule),
         capture(separatorRule)
-    ).map(function(tagName, classNames, fresh, separator) {
+    ).map(function(tagName, attributesList, fresh, separator) {
         var attributes = {};
         var options = {};
-        if (classNames.length > 0) {
-            attributes["class"] = classNames.join(" ");
-        }
+        attributesList.forEach(function(attribute) {
+            if (attribute.append && attributes[attribute.name]) {
+                attributes[attribute.name] += " " + attribute.value;
+            } else {
+                attributes[attribute.name] = attribute.value;
+            }
+        });
         if (fresh) {
             options.fresh = true;
         }
@@ -293,11 +298,30 @@ function decodeEscapeSequences(value) {
     });
 }
 
+var attributeRule = lop.rules.sequence(
+    lop.rules.tokenOfType("open-square-bracket"),
+    lop.rules.sequence.cut(),
+    lop.rules.sequence.capture(identifierRule),
+    lop.rules.tokenOfType("equals"),
+    lop.rules.sequence.capture(stringRule),
+    lop.rules.tokenOfType("close-square-bracket")
+).map(function(name, value) {
+    return {name: name, value: value, append: false};
+});
+
 var classRule = lop.rules.sequence(
     lop.rules.tokenOfType("dot"),
     lop.rules.sequence.cut(),
     lop.rules.sequence.capture(identifierRule)
-).head();
+).map(function(className) {
+    return {name: "class", value: className, append: true};
+});
+
+var attributeOrClassRule = lop.rules.firstOf(
+    "attribute or class",
+    attributeRule,
+    classRule
+);
 
 function parseString(rule, string) {
     var tokens = tokenise(string);
diff --git a/test/style-reader.tests.js b/test/style-reader.tests.js
index b77ce7e..93ddc79 100644
--- a/test/style-reader.tests.js
+++ b/test/style-reader.tests.js
@@ -54,6 +54,20 @@ test('styleReader.readHtmlPath', {
         assertHtmlPath("p.tip.help", expected);
     },
 
+    'reads attribute on element': function() {
+        var expected = htmlPaths.elements([
+            htmlPaths.element("p", {"lang": "fr"})
+        ]);
+        assertHtmlPath("p[lang='fr']", expected);
+    },
+
+    'reads multiple attributes on element': function() {
+        var expected = htmlPaths.elements([
+            htmlPaths.element("p", {"lang": "fr", "data-x": "y"})
+        ]);
+        assertHtmlPath("p[lang='fr'][data-x='y']", expected);
+    },
+
     'reads when element must be fresh': function() {
         var expected = htmlPaths.elements([
             htmlPaths.element("p", {}, {"fresh": true})