3 ms·

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 mat

by ngruhn 11mo 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 -> ... } } }

WJW 11mo ago
There are (some) guards available though? You could rewrite your example as: case x { n if x < 0 -> ... n if x > 10 -> ... n if x <= 10 -> ... } 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.
- tymscar 11mo ago
  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.
  - WJW 11mo ago
    There is though? https://tour.gleam.run/flow-control/guards/ https://tour.gleam.run/flow-control/guards/
- ngruhn 11mo ago
  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?
  - zelphirkalt 10mo ago
    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?
lpil 10mo ago
In Gleam we would typically write this code with `use`, which doesn’t introduce nesting.