From 4a6eba2ab8e3862b8a1365545112c79f51dd0209 Mon Sep 17 00:00:00 2001
From: takejohn <takejohn@takejohn.jp>
Date: Thu, 7 Aug 2025 15:48:20 +0900
Subject: [PATCH 1/2] =?UTF-8?q?=E6=95=B0=E5=80=A4=E3=83=AA=E3=83=86?=
 =?UTF-8?q?=E3=83=A9=E3=83=AB=E3=81=AB=E6=8C=87=E6=95=B0=E8=A1=A8=E8=A8=98?=
 =?UTF-8?q?=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/parser/scanner.ts              | 27 +++++++++++++++++++++++++++
 test/literals.ts                   | 27 +++++++++++++++++++++++++++
 unreleased/exponential-notation.md |  1 +
 3 files changed, 55 insertions(+)
 create mode 100644 unreleased/exponential-notation.md

diff --git a/src/parser/scanner.ts b/src/parser/scanner.ts
index cb86984f9..50dad9ada 100644
--- a/src/parser/scanner.ts
+++ b/src/parser/scanner.ts
@@ -10,6 +10,7 @@ const spaceChars = [' ', '\t'];
 const lineBreakChars = ['\r', '\n'];
 const digit = /^[0-9]$/;
 const wordChar = /^[A-Za-z0-9_]$/;
+const exponentIndicatorPattern = /^[eE]$/;
 
 /**
  * 入力文字列からトークンを読み取るクラス
@@ -436,12 +437,38 @@ export class Scanner implements ITokenStream {
 				throw new AiScriptSyntaxError('digit expected', pos);
 			}
 		}
+
+		let exponentIndicator = '';
+		let exponentSign = '';
+		let exponentAbsolute = '';
+		if (!this.stream.eof && exponentIndicatorPattern.test(this.stream.char as string)) {
+			exponentIndicator = this.stream.char as string;
+			this.stream.next();
+			if (!this.stream.eof && (this.stream.char as string) === '-') {
+				this.stream.next();
+				exponentSign = '-';
+			} else if (!this.stream.eof && (this.stream.char as string) === '+') {
+				this.stream.next();
+				exponentSign = '+';
+			}
+			while (!this.stream.eof && digit.test(this.stream.char)) {
+				exponentAbsolute += this.stream.char;
+				this.stream.next();
+			}
+			if (exponentAbsolute.length === 0) {
+				throw new AiScriptSyntaxError('exponent expected', pos);
+			}
+		}
+
 		let value: string;
 		if (fractional.length > 0) {
 			value = wholeNumber + '.' + fractional;
 		} else {
 			value = wholeNumber;
 		}
+		if (exponentIndicator.length > 0) {
+			value += exponentIndicator + exponentSign + exponentAbsolute;
+		}
 		return TOKEN(TokenKind.NumberLiteral, pos, { hasLeftSpacing, value });
 	}
 
diff --git a/test/literals.ts b/test/literals.ts
index 462cb5b7e..a9f500d88 100644
--- a/test/literals.ts
+++ b/test/literals.ts
@@ -58,6 +58,33 @@ describe('literal', () => {
 		eq(res, NUM(0.5));
 	});
 
+	test.concurrent('number (positive exponent without plus sign)', async () => {
+		const res = await exe(`
+		<: 1.2e3
+		`);
+		eq(res, NUM(1200));
+	});
+
+	test.concurrent('number (positive exponent with plus sign)', async () => {
+		const res = await exe(`
+		<: 1.2e+3
+		`);
+		eq(res, NUM(1200));
+	});
+
+	test.concurrent('number (negative exponent)', async () => {
+		const res = await exe(`
+		<: 1.2e-3
+		`);
+		eq(res, NUM(0.0012));
+	});
+
+	test.concurrent('number (missing exponent)', async () => {
+		assert.rejects(() => exe(`
+		<: 1.2e+
+		`), 'exponent expected');
+	});
+
 	test.concurrent('arr (separated by comma)', async () => {
 		const res = await exe(`
 		<: [1, 2, 3]
diff --git a/unreleased/exponential-notation.md b/unreleased/exponential-notation.md
new file mode 100644
index 000000000..15fb92137
--- /dev/null
+++ b/unreleased/exponential-notation.md
@@ -0,0 +1 @@
+- 数値リテラルを指数表記で記述できるようになりました。

From dbdd775916835cb13247c278f0e2970e337be8cd Mon Sep 17 00:00:00 2001
From: takejohn <takejohn@takejohn.jp>
Date: Thu, 7 Aug 2025 15:54:24 +0900
Subject: [PATCH 2/2] =?UTF-8?q?next()=E3=83=A1=E3=82=BD=E3=83=83=E3=83=89?=
 =?UTF-8?q?=E3=81=AE=E5=91=BC=E3=81=B3=E5=87=BA=E3=81=97=E4=BD=8D=E7=BD=AE?=
 =?UTF-8?q?=E3=81=8C=E6=B0=97=E3=81=AB=E3=81=AA=E3=82=8B=E3=81=AE=E3=81=A7?=
 =?UTF-8?q?=E5=A4=89=E6=9B=B4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/parser/scanner.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/parser/scanner.ts b/src/parser/scanner.ts
index 50dad9ada..ac55843fa 100644
--- a/src/parser/scanner.ts
+++ b/src/parser/scanner.ts
@@ -445,11 +445,11 @@ export class Scanner implements ITokenStream {
 			exponentIndicator = this.stream.char as string;
 			this.stream.next();
 			if (!this.stream.eof && (this.stream.char as string) === '-') {
-				this.stream.next();
 				exponentSign = '-';
-			} else if (!this.stream.eof && (this.stream.char as string) === '+') {
 				this.stream.next();
+			} else if (!this.stream.eof && (this.stream.char as string) === '+') {
 				exponentSign = '+';
+				this.stream.next();
 			}
 			while (!this.stream.eof && digit.test(this.stream.char)) {
 				exponentAbsolute += this.stream.char;