feat(for): Support filters

Closes #70

CHANGELOG.md

@@ -40,6 +40,14 @@
     {{ value|join:", " }}
     ```
 
+- `{% for %}` tag now supports filters.
+
+    ```html+django
+    {% for user in non_admins|default:admins %}
+      {{ user }}
+    {% endfor %}
+    ```
+
 ### Bug Fixes
 
 - Variables (`{{ variable.5 }}`) that reference an array index at an unknown

Sources/ForTag.swift

@@ -1,5 +1,5 @@
 class ForNode : NodeType {
-  let variable:Variable
+  let resolvable: Resolvable
   let loopVariable:String
   let nodes:[NodeType]
   let emptyNodes: [NodeType]
@@ -27,18 +27,19 @@ class ForNode : NodeType {
       _ = parser.nextToken()
     }
 
-    return ForNode(variable: variable, loopVariable: loopVariable, nodes: forNodes, emptyNodes:emptyNodes)
+    let filter = try parser.compileFilter(variable)
+    return ForNode(resolvable: filter, loopVariable: loopVariable, nodes: forNodes, emptyNodes:emptyNodes)
   }
 
-  init(variable:String, loopVariable:String, nodes:[NodeType], emptyNodes:[NodeType]) {
-    self.variable = Variable(variable)
+  init(resolvable: Resolvable, loopVariable:String, nodes:[NodeType], emptyNodes:[NodeType]) {
+    self.resolvable = resolvable
     self.loopVariable = loopVariable
     self.nodes = nodes
     self.emptyNodes = emptyNodes
   }
 
   func render(_ context: Context) throws -> String {
-    let values = try variable.resolve(context)
+    let values = try resolvable.resolve(context)
 
     if let values = values as? [Any] , values.count > 0 {
       let count = values.count

Sources/Parser.swift

@@ -84,7 +84,7 @@ public class TokenParser {
     throw TemplateSyntaxError("Invalid filter '\(name)'")
   }
 
-  func compileFilter(_ token: String) throws -> Resolvable {
+  public func compileFilter(_ token: String) throws -> Resolvable {
     return try FilterExpression(token: token, parser: self)
   }
 }

Tests/StencilTests/ForNodeSpec.swift

@@ -12,14 +12,14 @@ func testForNode() {
 
     $0.it("renders the given nodes for each item") {
       let nodes: [NodeType] = [VariableNode(variable: "item")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(context)) == "123"
     }
 
     $0.it("renders the given empty nodes when no items found item") {
       let nodes: [NodeType] = [VariableNode(variable: "item")]
       let emptyNodes: [NodeType] = [TextNode(text: "empty")]
-      let node = ForNode(variable: "emptyItems", loopVariable: "item", nodes: nodes, emptyNodes: emptyNodes)
+      let node = ForNode(resolvable: Variable("emptyItems"), loopVariable: "item", nodes: nodes, emptyNodes: emptyNodes)
       try expect(try node.render(context)) == "empty"
     }
 
@@ -29,7 +29,7 @@ func testForNode() {
       ])
 
       let nodes: [NodeType] = [VariableNode(variable: "item")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(any_context)) == "123"
     }
 
@@ -40,27 +40,56 @@ func testForNode() {
       ])
 
       let nodes: [NodeType] = [VariableNode(variable: "item")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(nsarray_context)) == "123"
     }
 #endif
 
     $0.it("renders the given nodes while providing if the item is first in the context") {
       let nodes: [NodeType] = [VariableNode(variable: "item"), VariableNode(variable: "forloop.first")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(context)) == "1true2false3false"
     }
 
     $0.it("renders the given nodes while providing if the item is last in the context") {
       let nodes: [NodeType] = [VariableNode(variable: "item"), VariableNode(variable: "forloop.last")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(context)) == "1false2false3true"
     }
 
     $0.it("renders the given nodes while providing item counter") {
       let nodes: [NodeType] = [VariableNode(variable: "item"), VariableNode(variable: "forloop.counter")]
-      let node = ForNode(variable: "items", loopVariable: "item", nodes: nodes, emptyNodes: [])
+      let node = ForNode(resolvable: Variable("items"), loopVariable: "item", nodes: nodes, emptyNodes: [])
       try expect(try node.render(context)) == "112233"
     }
+
+    $0.it("can render a filter") {
+      let templateString = "{% for article in ars|default:articles %}" +
+        "- {{ article.title }} by {{ article.author }}.\n" +
+        "{% endfor %}\n"
+
+      let context = Context(dictionary: [
+        "articles": [
+          Article(title: "Migrating from OCUnit to XCTest", author: "Kyle Fuller"),
+          Article(title: "Memory Management with ARC", author: "Kyle Fuller"),
+        ]
+      ])
+
+      let template = Template(templateString: templateString)
+      let result = try template.render(context)
+
+      let fixture = "" +
+        "- Migrating from OCUnit to XCTest by Kyle Fuller.\n" +
+        "- Memory Management with ARC by Kyle Fuller.\n" +
+        "\n"
+
+      try expect(result) == fixture
+    }
   }
 }
+
+
+fileprivate struct Article {
+  let title: String
+  let author: String
+}