Uh... destructors?

[Michel Fortin]

On 2011-02-23 12:01:15 -0500, Andrei Alexandrescu 
<SeeWebsiteForEmail at erdani.org> said:

> Because a pure unsafe function is useless.

I disagree. Suppose you have a function which is conceptually pure but 
requires a temporary 100 Mb matrix of doubles. Wouldn't it make sense 
to use malloc/free for this temporary storage instead of using the GC 
and risking the block never being collected because of a false pointer 
somewhere?

Should a function be prevented from being pure just because the 
programmer decided to use some tricks the compiler can't guaranty the 
safety of? There might be legitimate reasons for those tricks like 
optimization, solving GC memory problems, using special hardware for 
some calculation, etc.

@safe has an escape route (@trusted) for when you need to perform these 
things. If pure makes a function @safe by default, we need to have an 
escape route for it too ("@trusted pure" perhaps?). My only fear is 
that pure implying @safe needlessly complicates the attribute system.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/