Const sucks

[Bruce Adams]

Russell Lewis Wrote:

> Walter Bright wrote:
> > What we are trying to achieve:
> > 
> > a) utility for functional programming
> > b) better modularity by self-documenting interfaces better
> > c) be able to treat reference types as if they were value types (i.e. 
> > strings should behave to the user like value types, even though they are 
> > references)
> 
> Is there a way to express (for a pointer passed as a function parameter) 
> "the callee is allowed to modify this object through the pointer, but 
> the caller ensures that no other code will be modifying it at the same 
> time"?   Sort of a "you have exclusive write access" modifier?  Is that 
> a common enough case to even support?
> 
> Russ

That's an interesting concept. From the functions point of view it would compile as if it was invariant but the invariantness doesn't have a lifetime beyond the function. I think its slightly off topic here though, multi-threading / IPC is an entirely different kettle of bananas. How do you even declare whether a variable is shared or thread-local at the moment? This is only indirectly related to the const concept. What we have hear is "shared locked" versus "shared volatile" versus "local".

Bruce.