Taking inspiration from F# is always a great idea. One issue is going to be the
meaning of `:`. I think in variant type definitions, it should always be
followed by a type and there should never be a code block, while when pattern
matching, it should always be a code block and never a type.
Maybe differentiate between `variant` (new keyword where each variant is paired
with a named tuple) and `case`. For example:
type RequestResult = variant
of Success: string
of Failure: (int, string)
let response = case make_request()
of Success(payload):
echo payload
of Failure(err_no, err_msg):
echo &"Failed with error {err_no}: {err_msg}"
# Alternatively?
type RequestResult = variant
of Success: string
of Failure: tuple[err_no: int, err_msg: string]
let response = case make_request()
of Success as payload:
echo payload
of Failure as f:
echo &"Failed with error {f.err_no}: {f.err_msg}"
Run
@ingo The biggest issue I see with your sample is `either`, which I'd imagine
artificially limits the number of variants of what should be "unbounded"
variant functionality.
