Access outer loop context via its label

Sources/Stencil/ForTag.swift

@@ -96,6 +96,10 @@ class ForNode: NodeType {
       let count = values.count
       var result = ""
 
+      // collect parent loop contexts
+      let parentLoopContexts = (context["forloop"] as? [String: Any])?
+        .filter { ($1 as? [String: Any])?["label"] != nil } ?? [:]
+
       for (index, item) in zip(0..., values) {
         var forContext: [String: Any] = [
           "first": index == 0,
@@ -106,7 +110,9 @@ class ForNode: NodeType {
         ]
         if let label = label {
           forContext["label"] = label
+          forContext[label] = forContext
         }
+        forContext.merge(parentLoopContexts) { lhs, _ in lhs }
 
         var shouldBreak = false
         result += try context.push(dictionary: ["forloop": forContext]) {

Tests/StencilTests/ForNodeSpec.swift

@@ -514,6 +514,51 @@ final class ForNodeTests: XCTestCase {
       try expect(template.render(self.context)).toThrow()
     }
   }
+
+  func testAccessLabeled() {
+    it("can access labeled outer loop context from inner loop") {
+      let template = Template(templateString: """
+        {% outer: for item in 1...2 %}\
+        {% for item in items %}\
+        {{ forloop.counter }}-{{ forloop.outer.counter }},\
+        {% endfor %}---\
+        {% endfor %}
+        """)
+      try expect(template.render(self.context)) == """
+        1-1,2-1,3-1,---1-2,2-2,3-2,---
+        """
+    }
+
+    it("can access labeled outer loop from double inner loop") {
+      let template = Template(templateString: """
+        {% outer: for item in 1...2 %}{% for item in 1...2 %}\
+        {% for item in items %}\
+        {{ forloop.counter }}-{{ forloop.outer.counter }},\
+        {% endfor %}---{% endfor %}
+        {% endfor %}
+        """)
+      try expect(template.render(self.context)) == """
+        1-1,2-1,3-1,---1-1,2-1,3-1,---
+        1-2,2-2,3-2,---1-2,2-2,3-2,---
+
+        """
+    }
+
+    it("can access two labeled outer loop contexts from inner loop") {
+      let template = Template(templateString: """
+        {% outer1: for item in 1...2 %}{% outer2: for item in 1...2 %}\
+        {% for item in items %}\
+        {{ forloop.counter }}-{{ forloop.outer2.counter }}-{{ forloop.outer1.counter }},\
+        {% endfor %}---{% endfor %}
+        {% endfor %}
+        """)
+      try expect(template.render(self.context)) == """
+        1-1-1,2-1-1,3-1-1,---1-2-1,2-2-1,3-2-1,---
+        1-1-2,2-1-2,3-1-2,---1-2-2,2-2-2,3-2-2,---
+
+        """
+    }
+  }
 }
 
 // MARK: - Helpers