Phobos - pure, const, safe, nothrow

[monarch_dodra]

On Sunday, 29 September 2013 at 09:00:56 UTC, simendsjo wrote:
> What is the status of adding these annotations to phobos? It's 
> difficult to use these until phobos gets them. E.g. to! and 
> format is not pure.

Most of phobos is templated, meaning it relies on inference. 
These functions are pure/nothrow/safe, if their implementations 
are. Also, since they are templates, more often then not, they 
depend on their parameters, making them *conditionally* 
pure/nothrow/safe. Under such circumstances, there is simply no 
way to *mark* them as such (even if they are).

Efforts have been made recently for more "base" functions to be 
pure/nothrow (and ctfe btw), especially in std.string and 
std.array.

*If* they can be marked as such, then (right now), we are tending 
to mark them as such.

As for to!: it really depends on the parameters. Plus, to! is 
very complicated. If there are specific conversion types you 
think should be safe, but aren't, then please file a report, (or 
just quickly say what you had in mind here).

I have an open pull that makes string transcoding 
"to!SomeStringType(someOtherStringInstance)" safe and pure. It 
still needs to get reviewed though. It can't be nothrow due to 
UTF though.