One thing that helps in some of these cases, and not many people seem to
know, is that you can match "several levels" at once, like so:
type Top
= Some
| Other (Maybe Int)
-- and then match with
case value of
Other (Just n) ->
doStuffwith n
Other Nothing ->
doWithoutNumber
Some ->
doSomething
On Wednesday, March 29, 2017 at 7:40:40 PM UTC+3, Matthieu Pizenberg wrote:
>
> Multiple times in my projects, I happen to need nested pattern matching.
> Below is a raw extract of code (in an update) showing this need.
>
> Study.ScribblesMsg scribblesMsg ->
> case model.study.status of
> Study.Progressing steps ->
> case Pivot.getC steps of
> Study.ScribblesStep ( imageUrl, scribbles ) ->
> ( Scribbles.update scribblesMsg model scribbles
> , Cmd.none
> )
>
> _ ->
> ( model, Cmd.none )
>
> _ ->
> ( model, Cmd.none )
>
> Basically, this is a specific case of a generic following code:
>
> case f1 var1 of
> DataType2 var2 ->
> ...
> case fn varn of
> finalVar ->
> doSomethingOf finalVar
> _ ->
> otherwise
> ...
> _ ->
> otherwise
>
> Do you think there could exist a syntax enabling better handling of such a
> case?
> Have you encountered one in another langage maybe?
>
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