# CommonMark\CQL::__invoke

(cmark >= 1.1.0)

CommonMark\CQL::__invoke — CQL Execution

### Description

public CommonMark\CQL::__invoke ( CommonMark\Node `$root` , callable `$handler` )

Shall invoke the current CQL function on the given `root`, executing the given `handler` on entry to a CommonMark\Node

### Parameters

`root`

  the root node of a tree

`handler`

  should have the prototype:

  handler ( CommonMark\Node `$root` , CommonMark\Node `$entering` ) : bool|null
  - Should `handler` fail to return (void), or return null, CQL will continue executing
  - Should the handler return a truthy value, CQL will continue executing.
  - Should the handler return a falsy value, CQL will stop executing