wikimedia / mediawiki

	 * @throws MWException

	 * @return callable|null The old value of the mTagHooks array associated with the hook

	 */

	public function setHook( $tag, $callback ) {

		$tag = strtolower( $tag );

		if ( preg_match( '/[<>\r\n]/', $tag, $m ) ) {

			throw new MWException( "Invalid character {$m[0]} in setHook('$tag', ...) call" );

		}

		$oldVal = isset( $this->mTagHooks[$tag] ) ? $this->mTagHooks[$tag] : null;

		$this->mTagHooks[$tag] = $callback;

		if ( !in_array( $tag, $this->mStripList ) ) {

			$this->mStripList[] = $tag;

		}

		return $oldVal;

	}

	/**

	 * As setHook(), but letting the contents be parsed.

	 * @throws MWException

	 * @return null

	 */

	public function setFunctionTagHook( $tag, $callback, $flags ) {

		$tag = strtolower( $tag );

		if ( preg_match( '/[<>\r\n]/', $tag, $m ) ) {

			throw new MWException( "Invalid character {$m[0]} in setFunctionTagHook('$tag', ...) call" );

		}

		$old = isset( $this->mFunctionTagHooks[$tag] ) ?

			$this->mFunctionTagHooks[$tag] : null;

		$this->mFunctionTagHooks[$tag] = [ $callback, $flags ];

		if ( !in_array( $tag, $this->mStripList ) ) {

			$this->mStripList[] = $tag;

		}

		return $old;

	}

	/**

	 * Replace "<!--LINK-->" link placeholders with actual links, in the buffer