From 388f339de8385aaf352e664456d1e04fb131fe65 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 14:58:49 +0000
Subject: [PATCH 1/2] Initial plan


From 4c12a5e30f1e6be61461b0ad92eadaaabd6f7954 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 15:05:22 +0000
Subject: [PATCH 2/2] feat: add T_PERCENT to ArgumentLexeme for %4% style
 specifiers

Agent-Logs-Url: https://github.com/donatj/printf-parser/sessions/e0bec571-8995-42d0-95e4-b614c587fb7f

Co-authored-by: donatj <133747+donatj@users.noreply.github.com>
---
 src/ArgumentLexeme.php          |  3 +++
 test/Integration/ParserTest.php | 39 +++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/src/ArgumentLexeme.php b/src/ArgumentLexeme.php
index c945faf..cc5c88c 100644
--- a/src/ArgumentLexeme.php
+++ b/src/ArgumentLexeme.php
@@ -43,6 +43,8 @@ class ArgumentLexeme extends Lexeme {
 	public const T_INT_HEX = 'x';
 	/** @var string the argument is treated as an integer and presented as a hexadecimal number (with uppercase letters). */
 	public const T_INT_HEX_CAP = 'X';
+	/** @var string a percent-sign type specifier (e.g. `%4%`). Unlike `%%`, an argument must be supplied even though it is not used. */
+	public const T_PERCENT = '%';
 
 	public const VALID_T_TYPES = [
 		self::T_INT_AS_BINARY,
@@ -61,6 +63,7 @@ class ArgumentLexeme extends Lexeme {
 		self::T_INT_UNSIGNED,
 		self::T_INT_HEX,
 		self::T_INT_HEX_CAP,
+		self::T_PERCENT,
 	];
 
 	public const ARG_TYPE_MISSING = '';
diff --git a/test/Integration/ParserTest.php b/test/Integration/ParserTest.php
index 086d7bc..2d1b8b8 100644
--- a/test/Integration/ParserTest.php
+++ b/test/Integration/ParserTest.php
@@ -233,6 +233,24 @@ public static function parseStringProvider() : array {
 				'[=ll:1|||pos:|||left:||l][!=s:3]',
 				false,
 			],
+
+			'percent type with width' => [
+				'%4%',
+				'[%=4%:1|||pos:||4|left:|]',
+				true,
+			],
+
+			'percent type with long modifier' => [
+				'%l%',
+				'[%=l%:1|||pos:|||left:||l]',
+				true,
+			],
+
+			'percent type with flags and precision' => [
+				'%+5.5%',
+				'[%=+5.5%:1|||pos:1||5|left:|5]',
+				true,
+			],
 		];
 	}
 
@@ -377,6 +395,27 @@ public static function printfWithTypeProvider() : array {
 				[ 1 => ArgumentLexeme::ARG_TYPE_DOUBLE, ArgumentLexeme::ARG_TYPE_INT ],
 				true,
 			],
+
+			'percent type with width consumes one argument' => [
+				'%4%',
+				[ [ ArgumentLexeme::ARG_TYPE_MISSING ] ],
+				[ 1 => ArgumentLexeme::ARG_TYPE_MISSING ],
+				true,
+			],
+
+			'percent type with long modifier consumes one argument' => [
+				'%l%',
+				[ [ ArgumentLexeme::ARG_TYPE_MISSING ] ],
+				[ 1 => ArgumentLexeme::ARG_TYPE_MISSING ],
+				true,
+			],
+
+			'percent type with flags and precision consumes one argument' => [
+				'%+5.5%',
+				[ [ ArgumentLexeme::ARG_TYPE_MISSING ] ],
+				[ 1 => ArgumentLexeme::ARG_TYPE_MISSING ],
+				true,
+			],
 		];
 	}