Add Result.orElse and Option.orElse

[Dean Merchant]

These should work similarly to the corresponding or_ functions but with the arguments swapped:

Ok "the value I want"
|> Result.orElse (Ok "a default value")
= Ok “the value I want”

[fabrizzioalco]

Hey, i want to take a look at this.

[fabrizzioalco]

Can you give me more context please

[Dean Merchant]

Sure thing, I updated my original example to show the result.

Here is a bit more detail:

Result.or_ a b chooses a if it's Ok and otherwise chooses b. Result.orElse a b chooses b if it's Ok and otherwise chooses a. Particularly useful in a pipe:

Error "Snakes!"
|> Result.orElse (Ok "a default value")
= Ok "a default value"

The motivation for this function is being able to use Result.or_ in a pipeline (|> )

Feel free to shoot me a message (twitter @Dean177 / email deanmerchant@gmail / discord Dean#7331 ) if you aren't sure what you need to do as it will be a big help to streamline the process for future contributors

[shubham]

I had a question, does the Result module have an orElse function?

Because I couldn't find it in -> https://caml.inria.fr/pub/docs/manual-ocaml/libref/Result.html

[shubham]

Found it in bucklescript directory, but for Option type -> https://github.com/darklang/tablecloth/blob/master/bucklescript/src/TableclothOption.ml

[shubham]

Also there are 2 TableclothResult.ml one in native and one in bucklescript

[Paul Biggar]

Also there are 2 TableclothResult.ml one in native and one in bucklescript

Yeah, those are two different packages. One is tablecloth-native on opam, the other is tablecloth-bucklescript on npm

[Pomin Wu]

There seems already a Option.orElse but not a Result.orElse. Mind if I chip in?

[Paul Biggar]

Please do!