feat(for): Allow iterating over dictionary key and value

Closes #94

.swift-version

@@ -1 +1 @@
-3.0.1
+3.1

CHANGELOG.md

@@ -17,6 +17,14 @@
   {% endif %}
   ```
 
+- `for` block now allows you to iterate over array of tuples or dictionaries.
+
+  ```html+django
+  {% for key, value in thing %}
+    <li>{{ key }}: {{ value }}</li>
+  {% endfor %}
+  ```
+
 ### Bug Fixes
 
 - You can now use literal filter arguments which contain quotes.

Sources/ForTag.swift

@@ -53,13 +53,41 @@ class ForNode : NodeType {
     self.where = `where`
   }
 
+  func push<Result>(value: Any, context: Context, closure: () throws -> (Result)) rethrows -> Result {
+    if loopVariables.isEmpty {
+      return try context.push() {
+        return try closure()
+      }
+    }
+
+    if let value = value as? (Any, Any) {
+      let first = loopVariables[0]
+
+      if loopVariables.count == 2 {
+        let second = loopVariables[1]
+
+        return try context.push(dictionary: [first: value.0, second: value.1]) {
+          return try closure()
+        }
+      }
+
+      return try context.push(dictionary: [first: value.0]) {
+        return try closure()
+      }
+    }
+
+    return try context.push(dictionary: [loopVariables.first!: value]) {
+      return try closure()
+    }
+  }
+
   func render(_ context: Context) throws -> String {
     let resolved = try resolvable.resolve(context)
 
     var values: [Any]
 
     if let dictionary = resolved as? [String: Any], !dictionary.isEmpty {
-      values = Array(dictionary.keys)
+      values = dictionary.map { ($0.key, $0.value) }
     } else if let array = resolved as? [Any] {
       values = array
     } else {
@@ -68,7 +96,7 @@ class ForNode : NodeType {
 
     if let `where` = self.where {
       values = try values.filter({ item -> Bool in
-        return try context.push(dictionary: [loopVariables.first!: item]) { () -> Bool in
+        return try push(value: item, context: context) {
           try `where`.evaluate(context: context)
         }
       })
@@ -84,8 +112,10 @@ class ForNode : NodeType {
           "counter": index + 1,
         ]
 
-        return try context.push(dictionary: [loopVariables.first!: item, "forloop": forContext]) {
-          try renderNodes(nodes, context)
+        return try context.push(dictionary: ["forloop": forContext]) {
+          return try push(value: item, context: context) {
+            try renderNodes(nodes, context)
+          }
         }
       }.joined(separator: "")
     }

Tests/StencilTests/ForNodeSpec.swift

@@ -111,6 +111,13 @@ func testForNode() {
       let node = ForNode(resolvable: Variable("dict"), loopVariables: ["key"], nodes: nodes, emptyNodes: emptyNodes, where: nil)
       try expect(try node.render(context)) == "onetwo"
     }
+
+    $0.it("renders supports iterating over dictionary") {
+      let nodes: [NodeType] = [VariableNode(variable: "key"), VariableNode(variable: "value")]
+      let emptyNodes: [NodeType] = [TextNode(text: "empty")]
+      let node = ForNode(resolvable: Variable("dict"), loopVariables: ["key", "value"], nodes: nodes, emptyNodes: emptyNodes, where: nil)
+      try expect(try node.render(context)) == "oneItwoII"
+    }
   }
 }
 

docs/builtins.rst

@@ -19,6 +19,16 @@ A for loop allows you to iterate over an array found by variable lookup.
       {% endfor %}
     </ul>
 
+The ``for`` tag can iterate over dictionaries.
+
+.. code-block:: html+django
+
+    <ul>
+      {% for key, value in dict %}
+        <li>{{ key }}: {{ value }}</li>
+      {% endfor %}
+    </ul>
+
 The ``for`` tag can contain optional ``where`` expression to filter out
 elements on which this expression evaluates to false.