Ugly Types: Less Ugly Than History, Can We Do Better?

[bradrn]

@hostilefork

But given the choice, people would prefer switch type of and being able to think of type as being a value instead of a constraint. And with the TYPE-BLOCK! answer, there's some inkling of a direction of going that way:

switch type of x [
    logic! [...]  ; wouldn't be locked in a 1:1 heart:type ratio
    integer! [...]
    splice! [...]
]

In a way, I think this just goes to prove my point. Yet again, we see the most common thing to do with types is to match against them. And, in your words, when we’re matching types it’s nice if we’re not ‘locked in a 1:1 heart:type ratio’. To me, that again implies that it should be able to take constraints, like SWITCH/TYPE does… and you can’t do that simply by SWITCHing against TYPE OF.

I suppose the point I’m making is that TYPE OF is limited in a very fundamental sense: it can only ever return one value. Perhaps you can try to predict ahead of time what people will want to test, and add things like LOGIC! that to the output of TYPE OF… but then comes someone who wants to test if a number is EVEN?, and TYPE OF just doesn’t give you that information. That’s why I think it’s a good idea to keep TYPE OF a direct reflection of the heart-byte, and use other constructions for code which needs other things.

@hostilefork

With more complex types, you'd have to use something like DESTRUCTURE to get at what you were looking for. And maybe that would be interesting.

I’ll put my support strongly behind this. Pattern-matching is inordinately useful.

@hostilefork

I'm quite glad that you're thinking about it, and that you are able to take initiative and grok these problems well.

This is really where my expertise lies. I’m a Haskeller — I spend a long time thinking about types and type systems. Additionally, over the past year or two I’ve been learning a lot about structural type systems (i.e. ones which allow union and intersection), including making my own. So when I say things like ‘a Haskell-like type system isn’t a great fit for Rebol’, there’s some intuition behind those statements.

@hostilefork

I'm pleased and terrified that you're reading the source, but... there are some files that have decent organizations and comments to them, which can give you your bearings faster than reading something like a R3-Alpha or a Red.

Sure, but I just wanted to get some statistics quickly, and Ren-C itself is the largest Ren-C codebase that I know of. (Also, sometimes I get curious how things are implemented internally.)