fixed 'return -1' bug #40

Author: ppaska

package.json

@@ -1,6 +1,6 @@
 {
   "name": "jspython-interpreter",
-  "version": "2.1.15",
+  "version": "2.1.16",
   "description": "JSPython is a javascript implementation of Python language that runs within web browser or NodeJS environment",
   "keywords": [
     "python",

src/evaluator/evaluator.ts

@@ -60,7 +60,7 @@ export class Evaluator {
       }
       if (node.type === 'import') {
         // we can't use it here, because loader has to be promise
-        throw new Error(`Import is not support with 'eval'. Use method 'evalAsync' instead`);
+        throw new Error(`Import is not supported with 'eval'. Use method 'evalAsync' instead`);
       }
       try {
         lastResult = this.evalNode(node, blockContext);

src/interpreter.spec.ts

@@ -133,7 +133,7 @@ describe('Interpreter', () => {
   });
 
   it('json ignore last comma', () => {
-    expect(JSON.stringify(e.eval('[{a:1,}, {a:2},]'))).toBe(JSON.stringify([{ a: 1, }, { a: 2 },]));
+    expect(JSON.stringify(e.eval('[{a:1,}, {a:2},]'))).toBe(JSON.stringify([{ a: 1 }, { a: 2 }]));
   });
 
   [{ a: 1 }, { a: 2 }];
@@ -995,5 +995,20 @@ describe('Interpreter', () => {
     expect(interpreter.eval(script)).toBe(11);
   });
 
+  it('return -1', async () => {
+    const interpreter = Interpreter.create();
+
+    const script = `return -1`;
+    expect(await interpreter.evalAsync(script)).toBe(-1);
+    expect(interpreter.eval(script)).toBe(-1);
+  });
+
+  it('return -3.14', async () => {
+    const interpreter = Interpreter.create();
+
+    const script = `return -3.14`;
+    expect(await interpreter.evalAsync(script)).toBe(-3.14);
+    expect(interpreter.eval(script)).toBe(-3.14);
+  });
   //
 });

src/tokenizer/tokenizer.spec.ts

@@ -112,6 +112,13 @@ describe('Tokenizer => ', () => {
     expect(tokens[4][0]).toBe('d');
   });
 
+  it('return -1', async () => {
+    const tokens = new Tokenizer().tokenize('return -1');
+    expect(tokens.length).toBe(2);
+    expect(tokens[0][0]).toBe('return');
+    expect(tokens[1][0]).toBe(-1);
+  });
+
   /*
   it('3 - -2', async () => {
     let tokens = new Tokenizer().tokenize('3 - -2')

src/tokenizer/tokenizer.ts

@@ -278,6 +278,7 @@ export class Tokenizer {
       const prevToken = currentTokens.length !== 0 ? currentTokens[currentTokens.length - 1] : null;
       return (
         prevToken === null ||
+        getTokenValue(prevToken) === 'return' ||
         (getTokenType(prevToken) === TokenTypes.Operator && getTokenValue(prevToken) !== ')')
       );
     } else if (symbol === '.' && this.parseNumberOrNull(this.tokenText) !== null) {