Comment by ngruhn
1 month ago
I can live with these negatives. What irritates me the most is the lack of if/else or guards or some kind of dedicated case-distinction on booleans. Pattern matching is great but for booleans it can be kinda verbose. E.g.
case x < 0 {
True -> ...
False ->
case x > 10 {
True -> ...
False ->
case x <= 10 {
True -> ...
False -> ...
}
}
}
There are (some) guards available though? You could rewrite your example as:
Guards are a bit limited in that they cannot contain function calls, but that's a problem of the BEAM and not something Gleam could control.
Ah right, I remember now.
> Guards are a bit limited in that they cannot contain function calls,
I feel like that's not a small sacrifice.
> but that's a problem of the BEAM and not something Gleam could control.
Could Gleam desugar to a case expression like I wrote above?
Guards also eliminate checking for whether a pattern matching is comprehensive. Or do I remember wrong and the language does not check it at all?
You most likely asked an AI for this. They always think there is an `if` keyword in case statements in Gleam. There isn't one, sadly.
EDIT: I am wrong. Apparently there are, but it's a bit of a strange thing where they can only be used as clauses in `if` statements, and without doing any calculations.
There is though?
https://tour.gleam.run/flow-control/guards/
In Gleam we would typically write this code with `use`, which doesn’t introduce nesting.