feature: implement selectPrefix

closes #13

Author: Greg Bowler

src/Input.php

@@ -3,6 +3,7 @@
 
 use ArrayAccess;
 use Countable;
+use Gt\Input\Trigger\NeverTrigger;
 use Gt\Json\JsonDecodeException;
 use Gt\Json\JsonObject;
 use Gt\Json\JsonObjectBuilder;
@@ -243,14 +244,31 @@ public function select(string...$keys):Trigger {
 			}
 		}
 
-		return $this->newTrigger("with", ...$keys);
+		return $this->newTrigger("select", ...$keys);
 	}
 
 	/** @deprecated Use select() instead to avoid ambiguity with immutable `with` functions */
 	public function with(string...$keys):Trigger {
 		return $this->select(...$keys);
 	}
 
+	public function selectPrefix(string $prefix):Trigger {
+		$keys = [];
+
+		foreach($this->parameters as $key => $param) {
+			if(str_starts_with($key, $prefix)) {
+				array_push($keys, $key);
+			}
+		}
+
+		if($keys) {
+			return $this->when(...$keys);
+		}
+		else {
+			return new NeverTrigger($this);
+		}
+	}
+
 	/**
 	 * Return a Trigger that will pass all keys apart from the provided
 	 * keys to its callback.

src/Trigger/NeverTrigger.php

@@ -0,0 +1,16 @@
+<?php
+namespace Gt\Input\Trigger;
+
+class NeverTrigger extends Trigger {
+	public function call(callable $callback, string ...$args):Trigger {
+		return $this;
+	}
+
+	public function orCall(callable $callback, string ...$args):Trigger {
+		return $this;
+	}
+
+	public function fire():bool {
+		return false;
+	}
+}

test/phpunit/InputTest.php

@@ -710,6 +710,30 @@ public function testGetBodyJson_withQueryString():void {
 		self::assertSame(123, $sut->getInt("id"));
 	}
 
+	public function testSelectPrefix_noMatch():void {
+		$sut = new Input(["id" => 123]);
+		$trigger = $sut->selectPrefix("io_");
+
+		$triggered = false;
+		$trigger->call(function(...$args)use(&$triggered) {
+			$triggered = true;
+		});
+		$trigger->fire();
+		self::assertFalse($triggered);
+	}
+
+	public function testSelectPrefix_match():void {
+		$sut = new Input(["id" => 123, "io_database" => "connect"]);
+		$trigger = $sut->selectPrefix("io_");
+
+		$triggered = false;
+		$trigger->call(function(...$args)use(&$triggered) {
+			$triggered = true;
+		});
+		$trigger->fire();
+		self::assertTrue($triggered);
+	}
+
 	public static function dataRandomGetPost():array {
 		$data = [];