fix: infer return of the left hand of assignment operator

Author: lavyyy

CHANGELOG.md

@@ -1,5 +1,11 @@
 # @lunarclient/molang
 
+## 1.0.10
+
+### Patch Changes
+
+-   fix: infer return of the left hand of assignment operator
+
 ## 1.0.9
 
 ### Patch Changes

__tests__/custom/function.ts

@@ -135,6 +135,6 @@ test('Custom syntax', () => {
 		`return ({t.__scvar0.length=0;t.__scvar1=t.__scvar0;}+t.__scvar1);`
 	)
 	expect(customMolang.transform('f.test_no_return()')).toBe(
-		`return ({t.__scvar0=0;});`
+		`return ({t.__scvar0=0;}+t.__scvar1);`
 	)
 })

__tests__/inferReturn.ts

@@ -26,9 +26,15 @@ test('Infer return at end of statement with function', () => {
 test('Infer return at end of statement with negative variable', () => {
 	const statement = `v.y = 10;`
 
-	expect(molang.execute(statement)).toBe(0)
+	expect(molang.execute(statement)).toBe(10)
 
 	const statement2 = `-v.y;`
 
 	expect(molang.execute(statement2)).toBe(-10)
 })
+
+test('Infer return at end of assignment statement', () => {
+	const statement = `v.z = 10;`
+
+	expect(molang.execute(statement)).toBe(10)
+})

lib/parser/expressions/genericOperator.ts

@@ -35,3 +35,9 @@ export class GenericOperatorExpression extends Expression {
 		return `${this.left.toString()}${this.operator}${this.right.toString()}`
 	}
 }
+
+export function isGenericOperatorExpression(
+	expr: IExpression
+): expr is GenericOperatorExpression {
+	return expr.type === 'GenericOperatorExpression'
+}

lib/parser/parselets/statement.ts

@@ -5,6 +5,7 @@ import { IInfixParselet } from './infix'
 import { StatementExpression } from '../expressions/statement'
 import { StaticExpression } from '../expressions/static'
 import { ReturnExpression } from '../expressions'
+import { isGenericOperatorExpression } from '../expressions/genericOperator'
 
 export class StatementParselet implements IInfixParselet {
 	constructor(public precedence = 0) {}
@@ -78,14 +79,26 @@ export class StatementParselet implements IInfixParselet {
 
 			// Infer when statement should be returned
 			if (
-				!expressions.some((expr) => expr.isReturn) &&
-				!expressions[expressions.length - 1].isReturn &&
-				expressions[expressions.length - 1].type !==
-					'GenericOperatorExpression'
+				(!expressions.some((expr) => expr.isReturn) ||
+					!expressions[expressions.length - 1].isReturn) &&
+				!parser.match('CURLY_RIGHT', false)
 			) {
-				expressions[expressions.length - 1] = new ReturnExpression(
-					expressions[expressions.length - 1]
-				)
+				const lastExpression = expressions[expressions.length - 1]
+
+				// If the last expression is an assignment then append a return expression
+				if (
+					isGenericOperatorExpression(lastExpression) &&
+					lastExpression.operator === '='
+				) {
+					expressions.push(
+						new ReturnExpression(lastExpression.allExpressions[0])
+					)
+				} else {
+					// Anything else we just return the last expression
+					expressions[expressions.length - 1] = new ReturnExpression(
+						lastExpression
+					)
+				}
 			}
 		}
 

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "@lunarclient/molang",
-	"version": "1.0.9",
+	"version": "1.0.10",
 	"description": "Lunar Client's fork of bridge-core's molang parser",
 	"main": "lib/main.ts",
 	"files": [