No where in the post is there an example advocating dynamic invocation based on computed strings. No where. In fact, the more I read your responses the less I believe what you're saying has anything to do with the contents and examples of the post. We're on the same page here: dynamic invocation with computed strings: bad. spaghetti code. evil like eval.
> What does "dynamic invocation" have to do with higher-order functions?
Everything? Whether you're rolling your own or making use of PHP's built-in higher order functions, like array_map http://us.php.net/array_map, you're dynamically invoking something: a lambda, a function, an instance method, or a static method. Unfortunately these are distinct things in PHP. So with array_map its first argument is a callback, or something that returns true to is_callable as described in the post. What you're arguing is that you should never send a string name of a function to array_map, but should instead wrap the invocation in a lambda. So..
array_map(function($s) { return strtolowwer($s); }, $array);
array_map('strtolowwer', $array);
As for reflection, I'm all for it but in PHP a reflected function or method object is not a callable, thus cannot be passed to a function like array_map. Even if you could, I do not believe that, in PHP, the following is any less evil:
array_map(new ReflectionFunction('strtolowwer'), $array);
I really don't think you or I disagree on anything in terms of "best programming practices". The only thing we seem to disagree on is what this post was about and trying to demonstrate/advocate.