From 8050f876b197c929b5c3bd5d47bda8390e29acf1 Mon Sep 17 00:00:00 2001
From: Vignesh <vigneshshankar@gmail.com>
Date: Wed, 31 Oct 2018 10:18:26 +0800
Subject: [PATCH] Re-enable function expressions (#106)

* Revert "Disable function expressions (#96)"

This reverts commit 615fb51d4c50e54a00940b441a4e9285a1011005.

* Bump version
---
 package.json                                  |  2 +-
 .../__snapshots__/disallowed_syntax.ts.snap   |  4 ---
 src/__tests__/disallowed_syntax.ts            | 29 -------------------
 src/interpreter.ts                            |  3 ++
 src/syntaxTypes.ts                            |  5 ++--
 5 files changed, 6 insertions(+), 37 deletions(-)

diff --git a/package.json b/package.json
index d81769599..b63b458fa 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "js-slang",
-  "version": "0.1.13",
+  "version": "0.1.14",
   "description": "Javascript-based interpreter for slang, written in Typescript",
   "author": {
     "name": "Source Academy",
diff --git a/src/__tests__/__snapshots__/disallowed_syntax.ts.snap b/src/__tests__/__snapshots__/disallowed_syntax.ts.snap
index 9fedeab82..f1d6c96ec 100644
--- a/src/__tests__/__snapshots__/disallowed_syntax.ts.snap
+++ b/src/__tests__/__snapshots__/disallowed_syntax.ts.snap
@@ -8,8 +8,4 @@ exports[`Cannot leave blank expressions in for loops 3`] = `"Line 2: For stateme
 
 exports[`Cannot leave blank expressions in for loops 4`] = `"Line 2: For statement cannot have empty init,test,update expressions."`;
 
-exports[`Cannot use js function expressions 1`] = `"Line 2: Function expressions are not allowed"`;
-
 exports[`Cannot use update expressions 1`] = `"Line 3: Update expressions are not allowed"`;
-
-exports[`DEFINITELY CANNOT use named function declarations as expressions 1`] = `"Line 2: Function expressions are not allowed"`;
diff --git a/src/__tests__/disallowed_syntax.ts b/src/__tests__/disallowed_syntax.ts
index 15550c0ee..c6260d204 100644
--- a/src/__tests__/disallowed_syntax.ts
+++ b/src/__tests__/disallowed_syntax.ts
@@ -57,32 +57,3 @@ test("Cannot use update expressions", () => {
   });
 });
 
-test("Cannot use js function expressions", () => {
-  const code = `
-  map(function(x) {
-    return x + 1;
-  }, list(1));
-  `;
-  const context = mockContext(3);
-  const promise = runInContext(code, context, { scheduler: "preemptive" });
-  return promise.then(obj => {
-    expect(obj.status).toBe("error");
-    const errors = parseError(context.errors);
-    expect(errors).toMatchSnapshot();
-  });
-});
-
-test("DEFINITELY CANNOT use named function declarations as expressions", () => {
-  const code = `
-  map(function a(x) {
-    return x + 1;
-  }, list(1));
-  `;
-  const context = mockContext(3);
-  const promise = runInContext(code, context, { scheduler: "preemptive" });
-  return promise.then(obj => {
-    expect(obj.status).toBe("error");
-    const errors = parseError(context.errors);
-    expect(errors).toMatchSnapshot();
-  });
-});
diff --git a/src/interpreter.ts b/src/interpreter.ts
index 6a76a2a1b..4df480e33 100644
--- a/src/interpreter.ts
+++ b/src/interpreter.ts
@@ -175,6 +175,9 @@ export const evaluators: { [nodeType: string]: Evaluator<es.Node> } = {
     }
     return res
   },
+  FunctionExpression: function*(node: es.FunctionExpression, context: Context) {
+    return new Closure(node, currentFrame(context), context)
+  },
   ArrowFunctionExpression: function*(node: es.Function, context: Context) {
     return new ArrowClosure(node, currentFrame(context), context)
   },
diff --git a/src/syntaxTypes.ts b/src/syntaxTypes.ts
index 357c7861e..134f3e40c 100644
--- a/src/syntaxTypes.ts
+++ b/src/syntaxTypes.ts
@@ -11,6 +11,7 @@ const syntaxTypes: { [nodeName: string]: number } = {
   BinaryExpression: 1,
   LogicalExpression: 1,
   ConditionalExpression: 1,
+  FunctionExpression: 1,
   ArrowFunctionExpression: 1,
   Identifier: 1,
   Literal: 1,
@@ -44,9 +45,7 @@ const syntaxTypes: { [nodeName: string]: number } = {
   CatchClause: Infinity,
   DoWhileStatement: Infinity,
   ForInStatement: Infinity,
-  SequenceExpression: Infinity,
-  FunctionExpression: Infinity,
-
+  SequenceExpression: Infinity
 }
 
 export default syntaxTypes