toHash => pure, nothrow, const, @safe

[Jonathan M Davis]

On Tuesday, March 13, 2012 01:15:59 Stewart Gordon wrote:
> On 11/03/2012 23:54, Walter Bright wrote:
> > Consider the toHash() function for struct key types:
> > 
> > http://dlang.org/hash-map.html
> > 
> > And of course the others:
> > 
> > const hash_t toHash();
> > const bool opEquals(ref const KeyType s);
> > const int opCmp(ref const KeyType s);
> 
> <snip>
> 
> And what about toString?

That really should be too, but work is probably going to have to be done to 
make sure that format and std.conv.to can be pure, since they're pretty much 
required in most toString functions.

I believe that changes to toUTF8, toUTF16, and toUTF32 were made recently 
which are at least a major step in that direction for std.conv.to (since it 
uses them) and may outright make it so that it can be pure now (I'm not sure 
if anything else is preventing them from being pure). But I have no idea what 
the current state of format is with regards to purity, and if the changes to 
toUTFx weren't enough to make std.conv.to pure for strings, then more will 
need to be done there as well.

- Jonathan M Davis