Robert Klemme
12/23/2005 8:36:00 AM
Joe Van Dyk wrote:
> On 12/22/05, Edward Faulkner <ef@alum.mit.edu> wrote:
>> On Fri, Dec 23, 2005 at 09:00:31AM +0900, Joe Van Dyk wrote:
>>> def foo
>>> yield
>>> end
>>>
>>> foo do
>>> puts "hey"
>>> end
>>>
>>>
>>> What's the correct description of what is going on there? I've got
>>> a function foo. No arguments, right? Does it "take a block"? I
>>> know it gives control to the block, but I'm not sure of the correct
>>> terminology to use.
>>
>> It does indeed "take a block". The block argument is implicit. You
>> could make it explicit if you wanted to:
>>
>> def foo(&blk)
>> blk.call
>> end
Note, that this has some performance implications though.
>> In more general terms, any function that takes another function as an
>> argument (or returns one as a result) is known as a higher-order
>> function.
>
> Ok, thanks. I'm writing documentation for a domain-specific language
> (in Ruby) that I created. People who use it are probably programmers,
> but may not be experienced with Ruby, so I wanted to explain a little
> bit about what's going on behind the scenes.
You can as well call the block "anonymous function" or "anonymous
callback" IMHO. What I like about the "callback" variant is that it
precisely describes what's happening here: the caller provides a function
as hook that is called by the method.
Kind regards
robert