Recursion fix (#220)

tomblind · Perryvw · commit 3c96b40f6e86 · 2018-10-07T17:56:55.000+02:00
* Separated variable assignment from declaration when assigning to function expression or arrow function to allow recursion. fixes #187 * Added tests for recursive functions.
diff --git a/src/Transpiler.ts b/src/Transpiler.ts
@@ -1462,7 +1462,12 @@ export abstract class LuaTranspiler {
             const identifierName = this.transpileIdentifier(node.name);
             if (node.initializer) {
                 const value = this.transpileExpression(node.initializer);
-                return `local ${identifierName} = ${value}`;
+                if (ts.isFunctionExpression(node.initializer) || ts.isArrowFunction(node.initializer)) {
+                    // Separate declaration and assignment for functions to allow recursion
+                    return `local ${identifierName}; ${identifierName} = ${value}`;
+                } else {
+                    return `local ${identifierName} = ${value}`;
+                }
             } else {
                 return `local ${identifierName} = nil`;
             }
diff --git a/test/translation/lua/shorthandPropertyAssignment.lua b/test/translation/lua/shorthandPropertyAssignment.lua
@@ -1 +1 @@
-local f = function(x) return ({x = x}) end;
+local f; f = function(x) return ({x = x}) end;
diff --git a/test/unit/functions.spec.ts b/test/unit/functions.spec.ts
@@ -245,4 +245,28 @@ export class FunctionTests {
 
         Expect(result).toBe(3);
     }
+
+    @Test("Recursive function definition")
+    public recursiveFunctionDefinition(): void {
+        const result = util.transpileAndExecute(
+            `function f() { return typeof f; } return f();`);
+
+        Expect(result).toBe("function");
+    }
+
+    @Test("Recursive function expression")
+    public recursiveFunctionExpression(): void {
+        const result = util.transpileAndExecute(
+            `let f = function() { return typeof f; } return f();`);
+
+        Expect(result).toBe("function");
+    }
+
+    @Test("Recursive arrow function")
+    public recursiveArrowFunction(): void {
+        const result = util.transpileAndExecute(
+            `let f = () => typeof f; return f();`);
+
+        Expect(result).toBe("function");
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-local f = function(x) return ({x = x}) end;`
	`1`	`+local f; f = function(x) return ({x = x}) end;`