Add typechecker from java-slang

Author: bryanlohxz

src/commons/utils/JavaHelper.ts

@@ -2,28 +2,40 @@ import { compileFromSource } from 'java-slang/dist/compiler';
 import { BinaryWriter } from 'java-slang/dist/compiler/binary-writer';
 import setupJVM, { parseBin } from 'java-slang/dist/jvm';
 import { createModuleProxy, loadCachedFiles } from 'java-slang/dist/jvm/utils/integration';
+import { convertErrorsToReadableMsgs, parseProgram, typeCheck } from 'java-slang/dist/types';
 import { Context } from 'js-slang';
 import loadSourceModules from 'js-slang/dist/modules/loader';
 
 import Constants from './Constants';
 import DisplayBufferService from './DisplayBufferService';
 
 export async function javaRun(javaCode: string, context: Context) {
-  let compiled = {}
+  let compiled = {};
+
+  const stderr = (type: 'TypeCheck' | 'Compile' | 'Runtime', msg: string) => {
+    context.errors.push({
+      type: type as any,
+      severity: 'Error' as any,
+      location: { start: { line: -1, column: -1 }, end: { line: -1, column: -1 } },
+      explain: () => msg,
+      elaborate: () => msg
+    });
+  };
+
+  const typeCheckResult = typeCheck(parseProgram(javaCode));
+  if (typeCheckResult.hasTypeErrors) {
+    const typeErrMsg = convertErrorsToReadableMsgs(javaCode, typeCheckResult.errors).join('\n');
+    stderr('TypeCheck', typeErrMsg);
+    return Promise.resolve({ status: 'error' });
+  }
 
   try {
     const classFile = compileFromSource(javaCode);
     compiled = {
-      "Main.class": Buffer.from(new BinaryWriter().generateBinary(classFile)).toString('base64')
+      'Main.class': Buffer.from(new BinaryWriter().generateBinary(classFile)).toString('base64')
     };
   } catch (e) {
-    context.errors.push({
-      type: "CompileError" as any,
-      severity: "Error" as any,
-      location: { start: { line: -1, column: -1 }, end: { line: -1, column: -1 } },
-      explain: () => e,
-      elaborate: () => e
-    });
+    stderr('TypeCheck', e);
     return Promise.resolve({ status: 'error' });
   }
 
@@ -64,6 +76,7 @@ export async function javaRun(javaCode: string, context: Context) {
     }
     return parseBin(new DataView(bytes.buffer));
   };
+
   const loadNatives = async (path: string) => {
     // dynamic load modules
     if (path.startsWith('modules')) {
@@ -74,6 +87,7 @@ export async function javaRun(javaCode: string, context: Context) {
     }
     return await import(`java-slang/dist/jvm/stdlib/${path}.js`);
   };
+
   const stdout = (str: string) => {
     if (str.endsWith('\n')) {
       buffer.push(str);
@@ -85,24 +99,6 @@ export async function javaRun(javaCode: string, context: Context) {
       buffer.push(str);
     }
   };
-  const stderr = (msg: string) => {
-    context.errors.push({
-      type: 'Runtime' as any,
-      severity: 'Error' as any,
-      location: {
-        start: {
-          line: -1,
-          column: -1
-        },
-        end: {
-          line: -1,
-          column: -1
-        }
-      },
-      explain: () => msg,
-      elaborate: () => msg
-    });
-  };
 
   // load cached classfiles from IndexedDB
   return loadCachedFiles(() =>
@@ -128,7 +124,7 @@ export async function javaRun(javaCode: string, context: Context) {
             readFileSync: readClassFiles,
             readFile: loadNatives,
             stdout,
-            stderr,
+            stderr: (msg: string) => stderr('Runtime', msg),
             onFinish: () => {
               resolve(
                 context.errors.length