You could try elm-generic-dict to have arbitrary keys in dicts. On Monday, January 16, 2017 at 6:31:28 AM UTC-8, Austin Bingham wrote: > > Ah ha! That bit of syntax is exactly what I was looking for. That get's me > a lot of what I was hoping for. > > Regarding the use of helper functions, I agree in principle. But in my > particular case, at least, I think it's mostly an academic issue. I want to > distinguish between various "classes" of strings using the type system, but > mostly all I do with them is store them and use them as keys. > > One interesting issue I've run into is the use of single-contructor unions > as e.g. the key-type in a dict. As far as I can tell, I can't do something > like this: > > type Foo = Foo String > type alias FooDict = Dict Foo String > > because Foo isn't "comparable" and can't be made so. Is there some way to > do this, or is this just a limitation of elm? > > On Monday, January 16, 2017 at 2:49:46 PM UTC+1, Ian Mackenzie wrote: >> >> I agree with the point about adding helper functions for your data type >> so you can treat it as opaque in most places. For the rest, though, you can >> also use the slightly obscure 'as' syntax 'foo ((Foo s) as f) = ...' which >> allows you to use both 's' and 'f' in your function body (with the >> additional bonus of avoiding an extra object allocation). > >
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