feat: REPLの機能強化

docs/execution.md

@@ -36,3 +36,10 @@ $ npm run start
 ```
 $ npm run parse
 ```
+
+## 4. REPL上で実行
+コマンドライン上で対話的にコードを実行します。
+以下のコマンドを実行し、コードを入力します。
+```
+$npm run repl
+```

etc/aiscript.api.md

@@ -80,6 +80,11 @@ class AiScriptTypeError extends AiScriptError {
     pos: Pos;
 }
 
+// @public
+class AiScriptUnexpectedEOFError extends AiScriptSyntaxError {
+    constructor(pos: Pos, info?: unknown);
+}
+
 // @public
 class AiScriptUserError extends AiScriptRuntimeError {
     constructor(message: string, info?: unknown);
@@ -284,6 +289,7 @@ declare namespace errors {
         AiScriptError,
         NonAiScriptError,
         AiScriptSyntaxError,
+        AiScriptUnexpectedEOFError,
         AiScriptTypeError,
         AiScriptNamespaceError,
         AiScriptRuntimeError,

package.json

@@ -20,6 +20,7 @@
 	"scripts": {
 		"start": "node ./scripts/start.mjs",
 		"parse": "node ./scripts/parse.mjs",
+		"repl": "node ./scripts/repl.mjs",
 		"ts": "npm run ts-esm && npm run ts-dts",
 		"ts-esm": "tsc --outDir built/esm",
 		"ts-dts": "tsc --outDir built/dts --declaration true --emitDeclarationOnly true --declarationMap true",

console.js → scripts/repl.mjs

@@ -1,6 +1,6 @@
 import * as readline from 'readline/promises';
 import chalk from 'chalk';
-import { Parser, Interpreter, utils } from '@syuilo/aiscript';
+import { errors, Parser, Interpreter, utils } from '@syuilo/aiscript';
 const { valToString } = utils;
 
 const i = readline.createInterface({
@@ -12,9 +12,9 @@ console.log(
 `Welcome to AiScript!
 https://github.com/syuilo/aiscript
 
-Type 'exit' to end this session.`);
+Type '.exit' to end this session.`);
 
-const getInterpreter = () => new Interpreter({}, {
+const interpreter = new Interpreter({}, {
 	in(q) {
 		return i.question(q + ': ');
 	},
@@ -36,14 +36,34 @@ const getInterpreter = () => new Interpreter({}, {
 	}
 });
 
-let interpreter;
+async function getAst() {
+	let script = '';
+	let a = await i.question('>>> ');
+	while (true) {
+		try {
+			if (a === '.exit') return null;
+			script += a;
+			let ast = Parser.parse(script);
+			script = '';
+			return ast;
+		} catch(e) {
+			if (e instanceof errors.AiScriptUnexpectedEOFError) {
+				script += '\n';
+				a = await i.question('... ');
+			} else {
+				script = '';
+				throw e;
+			}
+		}
+	}
+}
+
 async function main(){
-	let a = await i.question('> ');
-	interpreter?.abort();
-	if (a === 'exit') return false;
 	try {
-		let ast = Parser.parse(a);
-		interpreter = getInterpreter();
+		let ast = await getAst();
+		if (ast == null) {
+			return false;
+		}
 		await interpreter.exec(ast);
 	} catch(e) {
 		console.log(chalk.red(`${e}`));

src/error.ts

@@ -1,3 +1,4 @@
+import { TokenKind } from './parser/token.js';
 import type { Pos } from './node.js';
 
 export abstract class AiScriptError extends Error {
@@ -12,7 +13,7 @@
 		this.info = info;
 
 		// Maintains proper stack trace for where our error was thrown (only available on V8)
 		if (Error.captureStackTrace) {
 			Error.captureStackTrace(this, AiScriptError);
 		}
 	}
@@ -40,6 +41,16 @@
 		super(`${message} (Line ${pos.line}, Column ${pos.column})`, info);
 	}
 }
+
+/**
+ * Unexpected EOF errors.
+ */
+export class AiScriptUnexpectedEOFError extends AiScriptSyntaxError {
+	constructor(pos: Pos, info?: unknown) {
+		super('unexpected EOF', pos, info);
+	}
+}
+
 /**
  * Type validation(parser/plugins/validate-type) errors.
  */

src/parser/scanner.ts

@@ -1,6 +1,7 @@
-import { AiScriptSyntaxError } from '../error.js';
+import { AiScriptSyntaxError, AiScriptUnexpectedEOFError } from '../error.js';
 import { CharStream } from './streams/char-stream.js';
 import { TOKEN, TokenKind } from './token.js';
+import { unexpectedTokenError } from './utils.js';
 
 import type { ITokenStream } from './streams/token-stream.js';
 import type { Token, TokenPosition } from './token.js';
@@ -96,7 +97,7 @@ export class Scanner implements ITokenStream {
 	*/
 	public expect(kind: TokenKind): void {
 		if (!this.is(kind)) {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[this.getTokenKind()]}`, this.getPos());
+			throw unexpectedTokenError(this.getTokenKind(), this.getPos());
 		}
 	}
 
@@ -456,7 +457,7 @@ export class Scanner implements ITokenStream {
 			switch (state) {
 				case 'string': {
 					if (this.stream.eof) {
-						throw new AiScriptSyntaxError('unexpected EOF', pos);
+						throw new AiScriptUnexpectedEOFError(pos);
 					}
 					if (this.stream.char === '\\') {
 						this.stream.next();
@@ -474,7 +475,7 @@ export class Scanner implements ITokenStream {
 				}
 				case 'escape': {
 					if (this.stream.eof) {
-						throw new AiScriptSyntaxError('unexpected EOF', pos);
+						throw new AiScriptUnexpectedEOFError(pos);
 					}
 					value += this.stream.char;
 					this.stream.next();
@@ -502,7 +503,7 @@ export class Scanner implements ITokenStream {
 				case 'string': {
 					// テンプレートの終了が無いままEOFに達した
 					if (this.stream.eof) {
-						throw new AiScriptSyntaxError('unexpected EOF', pos);
+						throw new AiScriptUnexpectedEOFError(pos);
 					}
 					// エスケープ
 					if (this.stream.char === '\\') {
@@ -538,7 +539,7 @@ export class Scanner implements ITokenStream {
 				case 'escape': {
 					// エスケープ対象の文字が無いままEOFに達した
 					if (this.stream.eof) {
-						throw new AiScriptSyntaxError('unexpected EOF', pos);
+						throw new AiScriptUnexpectedEOFError(pos);
 					}
 					// 普通の文字として取り込み
 					buf += this.stream.char;
@@ -550,7 +551,7 @@ export class Scanner implements ITokenStream {
 				case 'expr': {
 					// 埋め込み式の終端記号が無いままEOFに達した
 					if (this.stream.eof) {
-						throw new AiScriptSyntaxError('unexpected EOF', pos);
+						throw new AiScriptUnexpectedEOFError(pos);
 					}
 					// skip spasing
 					if (spaceChars.includes(this.stream.char)) {

src/parser/streams/token-stream.ts

@@ -1,5 +1,5 @@
-import { AiScriptSyntaxError } from '../../error.js';
 import { TOKEN, TokenKind } from '../token.js';
+import { unexpectedTokenError } from '../utils.js';
 import type { Token, TokenPosition } from '../token.js';
 
 /**
@@ -131,7 +131,7 @@ export class TokenStream implements ITokenStream {
 	*/
 	public expect(kind: TokenKind): void {
 		if (!this.is(kind)) {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[this.getTokenKind()]}`, this.getPos());
+			throw unexpectedTokenError(this.getTokenKind(), this.getPos());
 		}
 	}
 

src/parser/syntaxes/common.ts

@@ -1,5 +1,5 @@
 import { TokenKind } from '../token.js';
-import { AiScriptSyntaxError } from '../../error.js';
+import { AiScriptSyntaxError, AiScriptUnexpectedEOFError } from '../../error.js';
 import { NODE } from '../utils.js';
 import { parseStatement } from './statements.js';
 import { parseExpr } from './expressions.js';
@@ -75,6 +75,9 @@ export function parseParams(s: ITokenStream): Ast.Fn['params'] {
 			case TokenKind.CloseParen: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('separator expected', s.getPos());
 			}
@@ -116,6 +119,9 @@ export function parseBlock(s: ITokenStream): (Ast.Statement | Ast.Expression)[]
 			case TokenKind.CloseBrace: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('Multiple statements cannot be placed on a single line.', s.getPos());
 			}
@@ -184,6 +190,9 @@ function parseFnType(s: ITokenStream): Ast.TypeSource {
 					s.next();
 					break;
 				}
+				case TokenKind.EOF: {
+					throw new AiScriptUnexpectedEOFError(s.getPos());
+				}
 				default: {
 					throw new AiScriptSyntaxError('separator expected', s.getPos());
 				}

src/parser/syntaxes/expressions.ts

@@ -1,5 +1,5 @@
-import { AiScriptSyntaxError } from '../../error.js';
-import { NODE } from '../utils.js';
+import { AiScriptSyntaxError, AiScriptUnexpectedEOFError } from '../../error.js';
+import { NODE, unexpectedTokenError } from '../utils.js';
 import { TokenStream } from '../streams/token-stream.js';
 import { TokenKind } from '../token.js';
 import { parseBlock, parseOptionalSeparator, parseParams, parseType } from './common.js';
@@ -92,7 +92,7 @@ function parsePrefix(s: ITokenStream, minBp: number): Ast.Expression {
 			return NODE('not', { expr }, startPos, endPos);
 		}
 		default: {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[op]}`, startPos);
+			throw unexpectedTokenError(op, startPos);
 		}
 	}
 }
@@ -166,7 +166,7 @@ function parseInfix(s: ITokenStream, left: Ast.Expression, minBp: number): Ast.E
 				return NODE('or', { left, right }, startPos, endPos);
 			}
 			default: {
-				throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[op]}`, startPos);
+				throw unexpectedTokenError(op, startPos);
 			}
 		}
 	}
@@ -192,7 +192,7 @@ function parsePostfix(s: ITokenStream, expr: Ast.Expression): Ast.Expression {
 			}, startPos, s.getPos());
 		}
 		default: {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[op]}`, startPos);
+			throw unexpectedTokenError(op, startPos);
 		}
 	}
 }
@@ -243,7 +243,7 @@ function parseAtom(s: ITokenStream, isStatic: boolean): Ast.Expression {
 						break;
 					}
 					default: {
-						throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[element.kind]}`, element.pos);
+						throw unexpectedTokenError(element.kind, element.pos);
 					}
 				}
 			}
@@ -290,7 +290,7 @@ function parseAtom(s: ITokenStream, isStatic: boolean): Ast.Expression {
 			return expr;
 		}
 	}
-	throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[s.getTokenKind()]}`, startPos);
+	throw unexpectedTokenError(s.getTokenKind(), startPos);
 }
 
 /**
@@ -326,6 +326,9 @@ function parseCall(s: ITokenStream, target: Ast.Expression): Ast.Call {
 			case TokenKind.CloseParen: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('separator expected', s.getPos());
 			}
@@ -580,6 +583,9 @@ function parseObject(s: ITokenStream, isStatic: boolean): Ast.Obj {
 			case TokenKind.CloseBrace: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('separator expected', s.getPos());
 			}
@@ -624,6 +630,9 @@ function parseArray(s: ITokenStream, isStatic: boolean): Ast.Arr {
 			case TokenKind.CloseBracket: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('separator expected', s.getPos());
 			}

src/parser/syntaxes/statements.ts

@@ -1,5 +1,5 @@
 import { AiScriptSyntaxError } from '../../error.js';
-import { CALL_NODE, NODE } from '../utils.js';
+import { CALL_NODE, NODE, unexpectedTokenError } from '../utils.js';
 import { TokenKind } from '../token.js';
 import { parseBlock, parseDest, parseParams, parseType } from './common.js';
 import { parseExpr } from './expressions.js';
@@ -78,7 +78,7 @@ export function parseDefStatement(s: ITokenStream): Ast.Definition {
 			return parseFnDef(s);
 		}
 		default: {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[s.getTokenKind()]}`, s.getPos());
+			throw unexpectedTokenError(s.getTokenKind(), s.getPos());
 		}
 	}
 }
@@ -117,7 +117,7 @@ function parseVarDef(s: ITokenStream): Ast.Definition {
 			break;
 		}
 		default: {
-			throw new AiScriptSyntaxError(`unexpected token: ${TokenKind[s.getTokenKind()]}`, s.getPos());
+			throw unexpectedTokenError(s.getTokenKind(), s.getPos());
 		}
 	}
 	s.next();

src/parser/syntaxes/toplevel.ts

@@ -1,6 +1,6 @@
 import { NODE } from '../utils.js';
 import { TokenKind } from '../token.js';
-import { AiScriptSyntaxError } from '../../error.js';
+import { AiScriptSyntaxError, AiScriptUnexpectedEOFError } from '../../error.js';
 import { parseDefStatement, parseStatement } from './statements.js';
 import { parseExpr } from './expressions.js';
 
@@ -105,6 +105,9 @@ export function parseNamespace(s: ITokenStream): Ast.Namespace {
 			case TokenKind.CloseBrace: {
 				break;
 			}
+			case TokenKind.EOF: {
+				throw new AiScriptUnexpectedEOFError(s.getPos());
+			}
 			default: {
 				throw new AiScriptSyntaxError('Multiple statements cannot be placed on a single line.', s.getPos());
 			}

src/parser/utils.ts

@@ -1,3 +1,6 @@
+import { AiScriptSyntaxError, AiScriptUnexpectedEOFError } from '../error.js';
+import { TokenKind } from './token.js';
+import type { AiScriptError } from '../error.js';
 import type * as Ast from '../node.js';
 
 export function NODE<T extends Ast.Node['type']>(
@@ -29,3 +32,11 @@ export function CALL_NODE(
 		args,
 	}, start, end);
 }
+
+export function unexpectedTokenError(token: TokenKind, pos: Ast.Pos, info?: unknown): AiScriptError {
+	if (token === TokenKind.EOF) {
+		return new AiScriptUnexpectedEOFError(pos, info);
+	} else {
+		return new AiScriptSyntaxError(`unexpected token: ${TokenKind[token]}`, pos, info);
+	}
+}