Merge pull request #15 from thomscoder/soleModule

feat: support empty module

Author: thomscoder

compiler/compiler.go

@@ -169,6 +169,12 @@ func Compile(ast []types.AstNode) Module {
 			// MAGIC and VERSION don't change until a newer version of WebAssembly gets released
 			module = append(module, defaults.MAGIC...)
 			module = append(module, defaults.VERSION...)
+
+			// if the module is empty return
+			if node.Expression.Value == nil {
+				return module
+			}
+
 		case texts.FuncStatement:
 			// num of types (i32, f32, i64, f64) inside the function
 			functionType = append(functionType, sectionData{0x01}...)

compiler/parser.go

@@ -54,7 +54,12 @@ func Parser(tokens []types.Token) []types.AstNode {
 
 	currentToken := iterator.next(tokens)
 
+	// If the module is empty return the Ast with only the module
 	if currentToken.done {
+		nodes = append(nodes, types.AstNode{
+			Type:       texts.ModuleStatement,
+			Expression: types.ExpressionNode{},
+		})
 		return nodes
 	}
 
@@ -88,8 +93,9 @@ func parseStatement(currentToken *iteratorEmulatorStruct, eatToken func(val stri
 		case "module":
 			eatToken("module")
 			return types.AstNode{
-				Type:       texts.ModuleStatement,
-				Expression: types.ExpressionNode{},
+				Type: texts.ModuleStatement,
+				// Check if the module is empty by inspecting the next node
+				Expression: parseExpression(currentToken, eatToken, index),
 			}
 
 		case "func":
@@ -222,7 +228,12 @@ func parseExpression(currentToken *iteratorEmulatorStruct, eatToken func(val str
 
 		return log
 
-	}
+	// Make node aware of which node is coming after
+	default:
+		log := types.ExpressionNode{
+			Value: currentToken.token.Value,
+		}
 
-	return types.ExpressionNode{}
+		return log
+	}
 }

example/js/index.js

@@ -85,14 +85,25 @@ const runLunaAddition = async () => {
 
     try {
       const wasmer = await WebAssembly.instantiate(wasm);
-      const fn = Object.keys(wasmer.instance.exports)[0]
-      moduleContainer.innerHTML = `<p>Compiled successfully!\nExported function <span class="exported">${fn}</span></p>\n`
+      const fn = Object.keys(wasmer.instance.exports)[0];
+
+      // if module is empty, then make input section disappear
+      if (typeof wasmer.instance.exports[fn] == "undefined" && wasm.length == 8) {
+        moduleContainer.innerHTML = `<p>Module is <span class="exported">empty</span></p>\n`
+        input1.setAttribute("disabled", "true")
+        input2.setAttribute("disabled", "true")
+        btn.setAttribute('disabled', "true")
+      } else {
+        moduleContainer.innerHTML = `<p>Compiled successfully!\nExported function <span class="exported">${fn}</span></p>\n`
+        input1.removeAttribute("disabled")
+        input2.removeAttribute("disabled")
+        btn.removeAttribute('disabled')
+      }
 
       for (const hex of wasm) {
         moduleContainer.innerHTML += `<p class="hex-dump">${hex}</p>`
       }
 
-      btn.removeAttribute('disabled')
 
       btn.addEventListener('click', () => {
         const n1 = Number(input1.value);