Checking whether types can coerce to each other

[slate rivet]

I have types TA and TB. Can I check if TB can coerce to TA? If yes, how?

[ember mirage]

There are many ways to coerce types, which can have many properties. Can you be more specific?

[slate rivet]

I want to check whether @as(TA, @as(TB, some_value)) works.

[tender void]

the simple answer is to just do it

[slate rivet]

That would give a compile error tho

[tender void]

exactly

[slate rivet]

and I want to check programatically

so that's out of the question

[tender void]

then you'll need to use @typeInfo and compare all of the possible incompatibilities; there isn't anything for this in the stdlib

[slate rivet]

yikes

thanks

[honest temple]

@TypeOf(a, b) returns the peer-resolved type of a and b. It would be nice if it returned an optional when given more than one argument

[thick herald]

I think that'd be best as a separate built-in which takes the actual types, e.g. @TypeResolve(T1, T2).?

[slate rivet]

It would, yeah

[slate rivet]

I second this, @TypeOf needs a value, a @TypeResolve would be more applicable to more situations

[sterile vortex]

FWIW, just wanted to do exactly the same. A pity it's not possible (without manually parsing the std.builtin.Type structure and hopefully reimplementing the coercion rules correctly).

[sterile vortex]

This looks to me different than the original problem. Peer-resolution IIUC finds a common type that all arguments coerce to? In that case I'm not sure how it can be used to see if TA coerces to TB.