MDL-55224 core: Import PHP-CSS-Parser into core

Part of MDL-55071

lib/php-css-parser/Value/ValueList.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Sabberworm\CSS\Value;
+
+abstract class ValueList extends Value {
+
+	protected $aComponents;
+	protected $sSeparator;
+
+	public function __construct($aComponents = array(), $sSeparator = ',', $iLineNo = 0) {
+		parent::__construct($iLineNo);
+		if (!is_array($aComponents)) {
+			$aComponents = array($aComponents);
+		}
+		$this->aComponents = $aComponents;
+		$this->sSeparator = $sSeparator;
+	}
+
+	public function addListComponent($mComponent) {
+		$this->aComponents[] = $mComponent;
+	}
+
+	public function getListComponents() {
+		return $this->aComponents;
+	}
+
+	public function setListComponents($aComponents) {
+		$this->aComponents = $aComponents;
+	}
+
+	public function getListSeparator() {
+		return $this->sSeparator;
+	}
+
+	public function setListSeparator($sSeparator) {
+		$this->sSeparator = $sSeparator;
+	}
+
+	public function __toString() {
+		return $this->render(new \Sabberworm\CSS\OutputFormat());
+	}
+
+	public function render(\Sabberworm\CSS\OutputFormat $oOutputFormat) {
+		return $oOutputFormat->implode($oOutputFormat->spaceBeforeListArgumentSeparator($this->sSeparator) . $this->sSeparator . $oOutputFormat->spaceAfterListArgumentSeparator($this->sSeparator), $this->aComponents);
+	}
+
+}