The Crystal programming language | http://crystal-lang.org | Fund Crystal's development: http://is.gd/X7PRtI | Docs: http://crystal-lang.org/docs/ | API: http://crystal-lang.org/api/
I tried
brew install crystal and with --build-from-source
I am not that familiar with generics in Crystal, and I'm wondering if they are similar to Nim or Rust in that I can restrict a generic type parameter inline. The following is a Nim function definition, where
T is restricted to be of type Vec, which is used for both arguments and the return type. How can I do similar with Crystal, without a type alias or relying on the inferred call site types?proc abs[T: Vec](o: var T, v: T): var T = ...
i.e. not something the lang supports atm
<straight-shoota> This would be an example of a macro-based type restriction: https://github.com/crystal-lang/crystal/blob/13dd77ef01c0d55f2d43372f97c648ff81c737d9/src/slice.cr#L745-L748
Yeah I'm not a fan of making the body less readable to restrict a type or two
Also not realy a fan of Nim's inline restriction...would like a more readable
where or even overloading forall
I think I want to see the information in the
signature where it belongs
so :shrug: could be worse
:) Sure, not a deal breaker for me. I like Crystal's "for humans" philosophy, and adding line noise is not in line with that :)
Regardless, it is one thing I would use a lot if it was a thing.
I might play around with a macro sometime...for now it's not really needed. Thanks!
I thought about your macro generating the entire
def instead of mine just generating the body, and I decided on mine, for a couple reasons. 1) The readability as mentioned. 2) I would like to selectively choose which ones to annotate as always inlined, 3) I would like to add additional logic to some methods.
I'm trying to write a class method that initializes an Indexable type with random floats.
def self.rand(min = 0.0, max = 1.0)
res = new
res.each_index { |i| res[i] = Random.rand min..max }
res
endThis works, but I am wondering if this can be done more concisely/in one line instead of 3. Don't really want to macro around this if the language has something I could use that I don't know about.
I am thinking you are implying I write a
new that takes a block. That would help at least.
<hightower2> Hey why is https://shardbox.org/search?q=tasko.cr not finding https://github.com/bcardiff/tasko.cr ?
its a manual registry remember
<hightower2> shards.info finds it, but also only if trying by 'tasko.cr' rather than just 'tasko'
Does the
break statement break from the first while in its dynamic scope? Or are blocks handled specially by inlining to allow loop to have a block with a break statement?
If you're curious enough to test it ping me when you do, otherwise I'll say here when I have a compiler on hand.
Didn't expect my tiny compile time warning patch to get a heart from Müller 😮
I'm curious how loop works then. In code like
loop do
break
endwouldn't the break exit the yield block and then just continue the loop?
It seems like this would work more like skip than break
Right, I guess I was just curious how this deals with environments where the break isn't in the lexical scope of a while directly, but is only there via (potentially several layers of) blocks
I think maybe loop is a macro that expands to a while? Not a hundred on that
riza: That is one thing that confuses me, when to use
initialize vs new, despite reading the docs and fully understanding what is written.