variants of S.get, S.gets, and S.parseJson which use $.test

[davidchambers]

Using $.test in conjunction with S.get, S.gets, or S.parseJson is incredibly powerful. Consider these examples:

> S.parseJson ($.test ([]) ($.Array ($.Integer))) ('[1,2')
Nothing

> S.parseJson ($.test ([]) ($.Array ($.Integer))) ('[1,2,3]')
Just ([1, 2, 3])

> S.parseJson ($.test ([]) ($.Array ($.Integer))) ('[1,2,3,0.5]')
Nothing

We could provide _-suffixed variants for convenience:

get_ :: Type -> String -> Any -> Maybe a
gets_ :: Type -> Array String -> Any -> Maybe a
parseJson_ :: Type -> String -> Maybe a

One could then write:

> S.parseJson_ ($.Array ($.Integer)) ('[1,2')
Nothing

> S.parseJson_ ($.Array ($.Integer)) ('[1,2,3]')
Just ([1, 2, 3])

> S.parseJson_ ($.Array ($.Integer)) ('[1,2,3,0.5]')
Nothing

👍 / 👎 ?

[miwillhite]

👍 I like this a lot! Shaping data is one of the biggest and most important tasks I find myself in when working with the large, unkempt codebase that is my current job ;)

This is a great, non-intrusive (vs creating ADTs for everything) way of adding some safety around the data floating around my application.

[najlachamseddine]

I like it as it makes the type checking on data more explicit

[davidchambers]

#513 greatly improved the usability of S.get, S.gets, and S.parseJson, so variants of these functions are no longer necessary.