Would it not be possible to have anonymous union types that convert to a
broader union type automatically?
This would avoid partially instanciated enum while allowing the same kind of
uses, no?
template makeError(code: int): enum of Le: string =
result.Le = codeToString(code)
proc myFunction(): Either[string, int] =
let code = readFile(myVar)
if isError(code):
return makeError(code)
return Either.Ri(myVar.toInt())
Run
Also, why not completely anonymous union types based on the different branch
types?
type ErrorString = string
template makeError(code: int): ErrorString =
result = codeToString(code)
proc myFunction(): enum[ErrorString, int] =
let code = readFile(myVar)
if isError(code):
return makeError(code)
return myVar.toInt()
Run
The discriminant would then just be the type information.
