public function isFunctionUsed( $functions )
	{
		if ( is_string( $functions ) )
		{
			$functions = array( $functions );
		}

		$result = $this->traverseNodes( $this->exprTree, function( $node ) use( &$result, $functions )
		{
			// TODO Test the functions in this node and return false if any are found
			return true;
		} );

		return ! $result;
	}
public function isFunctionUsed( $functions )
	{
		if ( is_string( $functions ) )
		{
			$functions = array( $functions );
		}

		$result = $this->traverseNodes( $this->exprTree, function( $node ) use( &$result, $functions )
		{
			// TODO Test the functions in this node and return false if any are found
			return true;
		} );

		return ! $result;
	}
public function isFunctionUsed ( $ functions ) { if ( is_string ( $ functions ) ) { $ functions = array ( $ functions ) ; } $ result = $ this -> traverseNodes ( $ this -> exprTree , function ( $ node ) use ( & $ result , $ functions ) { // TODO Test the functions in this node and return false if any are found
 return true ; } ) ; return ! $ result ; }
Checks to see is one or any of a collection of functions are used in an expression
@param array $functions
Checks to see is one or any of a collection of functions are used in an expression