@safe status

[Michel Fortin]

On 2010-02-08 17:20:21 -0500, Andrei Alexandrescu 
<SeeWebsiteForEmail at erdani.org> said:

> Michel Fortin wrote:
>> On 2010-02-08 16:21:31 -0500, bearophile <bearophileHUGS at lycos.com> said:
>> 
>>> Michel Fortin:
>>>> But unsafe functions can give whatever pointer they want to a safe function,<
>>> 
>>> Can pointers be used in safe modules/functions?
>> 
>> Yes. And object references too. And arrays. All those are pointers of 
>> some sort. You wouldn't go very far without them.
> 
> Pointers undergo significantly less control than arrays and object references.

Yes. But an unsafe function can still give a bad pointer to a safe 
function and have the safe function corrupt some memory.

The whole point is that you don't have a "safe pointer" type for giving 
only safe pointers to safe functions: a safe function will accept any 
pointer. The same should be true for delegates: an unsafe function 
should be able to call any delegate you feed it with. But only unsafe 
functions should be allowed to create an unsafe delegate in the first 
place.

It could be achieved simply by abolishing the @safe qualifier for 
variables of type delegate or function pointer and restricting @safe 
code so that it can only get the address of another @safe function.

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