Filters: added rtrim and ltrim filter

src/Latte/Essential/Filters.php

@@ -487,6 +487,44 @@ public static function trim(FilterInfo $info, string $s, string $charlist = " \t
 
 		return $s;
 	}
+
+
+	/**
+	 * Strip whitespace (or other characters) from the beginning of a string.
+	 */
+	public static function ltrim(FilterInfo $info, string $s, string $charlist = " \t\n\r\0\x0B\u{A0}"): string
+	{
+	    if ($charlist === "") {
+		return $s;
+	    }
+
+	    $charlist = preg_quote($charlist, '#');
+	    $s = preg_replace('#^[' . $charlist . ']+#Du', '', $s);
+	    if (preg_last_error() || $s === null) {
+		throw new Latte\RuntimeException(preg_last_error_msg());
+	    }
+
+	    return $s;
+	}
+
+
+	/**
+	 * Strip whitespace (or other characters) from the end of a string.
+	 */
+	public static function rtrim(FilterInfo $info, string $s, string $charlist = " \t\n\r\0\x0B\u{A0}"): string
+	{
+	    if ($charlist === "") {
+		return $s;
+	    }
+
+	    $charlist = preg_quote($charlist, '#');
+	    $s = preg_replace('#[' . $charlist . ']+$#Du', '', $s);
+	    if (preg_last_error() || $s === null) {
+		throw new Latte\RuntimeException(preg_last_error_msg());
+	    }
+
+	    return $s;
+	}
 
 
 	/**

tests/filters/ltrim.phpt

@@ -0,0 +1,25 @@
+<?php declare(strict_types=1);
+
+/**
+ * Test: Latte\Essential\Filters::ltrim()
+ */
+
+use Latte\ContentType;
+use Latte\Essential\Filters;
+use Latte\Runtime\FilterInfo;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$info = new FilterInfo(ContentType::Text);
+Assert::same('x', Filters::ltrim($info, " \t\n\r\x00\x0B\u{A0}x"));
+Assert::same('a b ', Filters::ltrim($info, ' a b '));
+Assert::same(' a b ', Filters::ltrim($info, ' a b ', ''));
+Assert::same('e-', Filters::ltrim($info, "\u{158}e-", "\u{158}-")); // Ře-
+
+Assert::exception(
+	fn() => Filters::ltrim($info, "\xC2x\xA0"),
+	Latte\RuntimeException::class,
+	null,
+);

tests/filters/rtrim.phpt

@@ -0,0 +1,25 @@
+<?php declare(strict_types=1);
+
+/**
+ * Test: Latte\Essential\Filters::rtrim()
+ */
+
+use Latte\ContentType;
+use Latte\Essential\Filters;
+use Latte\Runtime\FilterInfo;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$info = new FilterInfo(ContentType::Text);
+Assert::same('x', Filters::rtrim($info, "x \t\n\r\x00\x0B\u{A0}"));
+Assert::same(' a b', Filters::rtrim($info, ' a b '));
+Assert::same(' a b ', Filters::rtrim($info, ' a b ', ''));
+Assert::same('e', Filters::rtrim($info, "e\u{158}-", "\u{158}-")); // eŘ-
+
+Assert::exception(
+	fn() => Filters::rtrim($info, "\xC2x\xA0"),
+	Latte\RuntimeException::class,
+	null,
+);