crystal-lang/crystal

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/

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@FromIRC

<oprypin> macros need to be evaluated before everything but also after everything :⁠D

<oprypin> in simple cases macros are evaluated before everything, but for example if you refer to the current type in the macro, that delays the expansion until the type's semantics are figured out

@marceloboeira

macros need to be evaluated before everything but also after everything :⁠D
http://www.reactiongifs.com/wp-content/uploads/2013/10/tim-and-eric-mind-blown.gif

@marceloboeira

https://github.com/marceloboeira/option.cr

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@FromIRC

<Papierkorb> Why

@marceloboeira

just experimenting, I wanted to do it with macros, but then I've realised that it does not make any sense considering that you might have dynamic results

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@FromIRC

<Papierkorb> For real code, you'd just rely on Nil

<Papierkorb> In your example, it'd simply be a Unsafe.new.io || "Empty..."

Cris Ward

@crisward

Just need 4,027 more stars to overtake ruby... https://github.com/showcases/programming-languages :wink:

@marceloboeira

But considering everything can be nil,
Unsafe.new.io.foo.bar
you would have to

(((Unsafe.new.io || "default").foo) || "default_2").bar

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@FromIRC

<Papierkorb> No

<Papierkorb> Everything can't be nil

@marceloboeira

not everything, but the calls to unsafe things

IO related

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@FromIRC

<Papierkorb> That's the whole point. Nil is a type on its own in Crystal. Try this: def foo(a : String); a; end; foo(nil) - Won't work

<Papierkorb> ..huh

<Papierkorb> IO is a type. If you expect an IO, or pledge to return an IO, you can only return that, no nil

<Papierkorb> Impossible. If you do find a way, it's a serious compiler bug

<RX14> if you do find a way you'll get segfaults lol

<Papierkorb> The only way to 'escape' having to return something matching the method prototype is raising an Exception. Another common theme is something like this: def read_input : String?; ...; end. It may return a String, or nil. In this case, the compiler will force you to work with the result in a type-safe manner

@marceloboeira

e.g.:

User.where(foo: "bar").first.name

will never be nil?

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@FromIRC

<Papierkorb> If #where, #first and #name are not nil-able, never.

<RX14> @marceloboeira have a pay with nil, you'll find out what works and what doesn't.

@marceloboeira

you mean because of the nilable String?, ok, fair enough

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@FromIRC

<Papierkorb> The type system of Crystal alone safes you from having to clutter your code with Just(x) etc.

John Jansen

@johnjansen

ok people, can someone point me at the solution to this on Ubuntu 16.04.2 LTS

$ crystal build test.cr --release
crystal: /var/cache/omnibus/src/llvm/llvm-3.8.1.src/lib/CodeGen/LexicalScopes.cpp:160: llvm::LexicalScope* llvm::LexicalScopes::getOrCreateRegularScope(const llvm::DILocalScope*): Assertion `cast<DISubprogram>(Scope)->describes(MF->getFunction())' failed.
/usr/bin/crystal: line 102:  7523 Aborted                 (core dumped) "$INSTALL_DIR/embedded/bin/crystal" "$@"

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@FromIRC

<Papierkorb> That is a compiler crash

<Papierkorb> Can you share the code?

Nick Franken

@fridgerator

@johnjansen its an issue with the latest build

crystal-lang/crystal#4719

John Jansen

@johnjansen

thanks @fridgerator, i feel another broken record coming on ;-)

Nick Franken

@fridgerator

lol

nah there is a workaround for this one

add --no-debug

John Jansen

@johnjansen

thanks, reading all that would have taken an age

Cris Ward

@crisward

@johnjansen Just tried compiling with --release and --no-debug and I'm get a strange bug where my app doesn't recognise '/' as a path. Will try and isolate the specific bug tomorrow.

John Jansen

@johnjansen

interesting

Cris Ward

@crisward

It's fine without --release, which means it's probably something to do with an llvm optimisation.

Rubi

@codenoid

morning ,,, :hatching_chick:

Rubi

@codenoid

btw gets method (from IO) wont work if i compile it with S E N T R Y

Dominic Muller

@domgetter

I can build just fine, but when I build --release, I'm getting this error: https://gist.github.com/domgetter/2da07138559cc4b86d3bcdbda66da398

Any thoughts?

John Jansen

@johnjansen

add —no-debug its a bug with 0.23.1

thats double dash

Dominic Muller

@domgetter

oh man I just had to scroll up 10 lines to see someone else with the issue. Thanks @johnjansen

John Jansen

@johnjansen

it was me ;-)

Dominic Muller

@domgetter

Now I can get back to figuring out why my SDL event handling is slow

bigDaddyS1oth

@bigDaddyS1oth

Hey all, it's been awhile. I'm on a new comfy Linux distro called Void and I'm installing Crystal from source, and I was curious if it's taken awhile for those of you who've done the same.

make is just taking awhile but I did give it the -si flags so that's probably why.

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@FromIRC

<hightower2> Did you run it with -jX?

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