feat: 式に符号を使えるように

etc/aiscript.api.md

@@ -150,6 +150,8 @@ declare namespace Ast {
         SubAssign,
         Assign,
         Expression,
+        Plus,
+        Minus,
         Not,
         Pow,
         Mul,
@@ -298,7 +300,7 @@ type Exists = NodeBase & {
 function expectAny(val: Value | null | undefined): asserts val is Value;
 
 // @public (undocumented)
-type Expression = If | Fn | Match | Block | Exists | Tmpl | Str | Num | Bool | Null | Obj | Arr | Not | Pow | Mul | Div | Rem | Add | Sub | Lt | Lteq | Gt | Gteq | Eq | Neq | And | Or | Identifier | Call | Index | Prop;
+type Expression = If | Fn | Match | Block | Exists | Tmpl | Str | Num | Bool | Null | Obj | Arr | Plus | Minus | Not | Pow | Mul | Div | Rem | Add | Sub | Lt | Lteq | Gt | Gteq | Eq | Neq | And | Or | Identifier | Call | Index | Prop;
 
 // @public (undocumented)
 const FALSE: {
@@ -502,6 +504,12 @@ type Meta = NodeBase & {
     value: Expression;
 };
 
+// @public (undocumented)
+type Minus = NodeBase & {
+    type: 'minus';
+    expr: Expression;
+};
+
 // @public (undocumented)
 type Mul = NodeBase & {
     type: 'mul';
@@ -598,6 +606,12 @@ export type ParserPlugin = (nodes: Ast.Node[]) => Ast.Node[];
 // @public (undocumented)
 export type PluginType = 'validate' | 'transform';
 
+// @public (undocumented)
+type Plus = NodeBase & {
+    type: 'plus';
+    expr: Expression;
+};
+
 // @public
 type Pos = {
     line: number;

src/interpreter/index.ts

@@ -411,7 +411,7 @@
 
 			case 'loop': {
 				// eslint-disable-next-line no-constant-condition
 				while (true) {
 					const v = await this._run(node.statements, scope.createChildScope(), callStack);
 					if (v.type === 'break') {
 						break;
@@ -642,6 +642,24 @@
 				}
 			}
 
+			case 'plus': {
+				const v = await this._eval(node.expr, scope, callStack);
+				if (isControl(v)) {
+					return v;
+				}
+				assertNumber(v);
+				return v;
+			}
+
+			case 'minus': {
+				const v = await this._eval(node.expr, scope, callStack);
+				if (isControl(v)) {
+					return v;
+				}
+				assertNumber(v);
+				return NUM(-v.value);
+			}
+
 			case 'not': {
 				const v = await this._eval(node.expr, scope, callStack);
 				if (isControl(v)) {
@@ -813,7 +831,14 @@
 				}
 			}
 
+			case 'namedTypeSource':
+			case 'fnTypeSource':
+			case 'attr': {
+				throw new Error('invalid node type');
+			}
+
 			default: {
+				node satisfies never;
 				throw new Error('invalid node type');
 			}
 		}
@@ -884,7 +909,7 @@
 	public pause(): void {
 		if (this.pausing) return;
 		let resolve: () => void;
 		const promise = new Promise<void>(r => { resolve = () => r(); });
 		this.pausing = { promise, resolve: resolve! };
 		for (const handler of this.pauseHandlers) {
 			handler();

src/node.ts

@@ -133,6 +133,8 @@ export type Expression =
 	Null |
 	Obj |
 	Arr |
+	Plus |
+	Minus |
 	Not |
 	Pow |
 	Mul |
@@ -162,6 +164,16 @@ export function isExpression(x: Node): x is Expression {
 	return expressionTypes.includes(x.type);
 }
 
+export type Plus = NodeBase & {
+	type: 'plus'; // 正号
+	expr: Expression; // 式
+};
+
+export type Minus = NodeBase & {
+	type: 'minus'; // 負号
+	expr: Expression; // 式
+};
+
 export type Not = NodeBase & {
 	type: 'not'; // 否定
 	expr: Expression; // 式

src/parser/syntaxes/expressions.ts

@@ -69,24 +69,16 @@ function parsePrefix(s: ITokenStream, minBp: number): Ast.Expression {
 
 	switch (op) {
 		case TokenKind.Plus: {
-			// 数値リテラル以外は非サポート
 			if (expr.type === 'num') {
 				return NODE('num', { value: expr.value }, startPos, endPos);
-			} else {
-				throw new AiScriptSyntaxError('currently, sign is only supported for number literal.', startPos);
 			}
-			// TODO: 将来的にサポートされる式を拡張
-			// return NODE('plus', { expr }, startPos, endPos);
+			return NODE('plus', { expr }, startPos, endPos);
 		}
 		case TokenKind.Minus: {
-			// 数値リテラル以外は非サポート
 			if (expr.type === 'num') {
 				return NODE('num', { value: -1 * expr.value }, startPos, endPos);
-			} else {
-				throw new AiScriptSyntaxError('currently, sign is only supported for number literal.', startPos);
 			}
-			// TODO: 将来的にサポートされる式を拡張
-			// return NODE('minus', { expr }, startPos, endPos);
+			return NODE('minus', { expr }, startPos, endPos);
 		}
 		case TokenKind.Not: {
 			return NODE('not', { expr }, startPos, endPos);

src/parser/visit.ts

@@ -49,8 +49,16 @@ function visitNodeInner(node: Ast.Node, fn: (node: Ast.Node, ancestors: Ast.Node
 			result.dest = visitNodeInner(result.dest, fn, ancestors) as Ast.Assign['dest'];
 			break;
 		}
+		case 'plus': {
+			result.expr = visitNodeInner(result.expr, fn, ancestors) as Ast.Plus['expr'];
+			break;
+		}
+		case 'minus': {
+			result.expr = visitNodeInner(result.expr, fn, ancestors) as Ast.Minus['expr'];
+			break;
+		}
 		case 'not': {
-			result.expr = visitNodeInner(result.expr, fn, ancestors) as Ast.Return['expr'];
+			result.expr = visitNodeInner(result.expr, fn, ancestors) as Ast.Not['expr'];
 			break;
 		}
 		case 'if': {

test/syntax.ts

@@ -1314,6 +1314,26 @@ describe('operators', () => {
 
 });
 
+describe('plus', () => {
+	test.concurrent('Basic', async () => {
+		const res = await exe(`
+		let a = 1
+		<: +a
+		`);
+		eq(res, NUM(1));
+	})
+})
+
+describe('minus', () => {
+	test.concurrent('Basic', async () => {
+		const res = await exe(`
+		let a = 1
+		<: -a
+		`);
+		eq(res, NUM(-1));
+	})
+})
+
 describe('not', () => {
 	test.concurrent('Basic', async () => {
 		const res = await exe(`

unreleased/unary-sign-operators.md

@@ -0,0 +1 @@
+- 単項演算子の正号 `+`・負号 `-`が数値リテラル以外の式にも使用できるようになりました。