How to read this signature? (writeTo in DIP9)

[Graham Fawcett]

On Fri, 19 Nov 2010 14:43:03 -0500, bearophile wrote:

> Graham Fawcett:
> 
>> void writeTo(scope delegate(in char[] data) sink,
>> 	     string format = null) const
>> 
>> // from http://prowiki.org/wiki4d/wiki.cgi?LanguageDevel/DIPs/DIP9
>> 
>> Particularly, how does "scope" modify the delegate, and what is the
>> meaning of the trailing "const"?
> 
> "scope" means that the sink delegate is not a true closure, its
> outer scope is never allocated on the heap. "const" member functions
> means that inside it the "this" is const, so writeTo() can't modify
> the class/struct attributes.

Ah! Thanks very much, bearophile!

Graham