Const, strings, and other things.

[Paul Findlay]

> It has something to do with it.  If you have a function like so:
> 
> void drawImage(Image i, int x, int y) ...
> 
> And Image is a class type, do you expect images that you pass in to be
> modified?  No, because that would be stupid.
Yeah, but it happens with code I use in ruby land. This is a bug I reported:
http://projects.jkraemer.net/acts_as_ferret/ticket/181
(happens easily since ruby strings are like references to classes).

Having optional const may not have prevented the error, but if ruby had
something like a const attribute I imagine I could have simply added it and
tracked down the modification by waiting for a compiler/runtime error
rather than tracing the whole flow of the code manually.

I don't really know, but I wish the D compiler had support for ensuring
things that could be const are, and that functions that can return
null-references get checked their return value checked by their users. I
don't think it should substitute for programming habits, but a compiler
should be able to do so much more grunt work.

 - Paul