I afraid you missed my point, I might have expressed it poorly. Let's
assume I have a simple type: {is_atom(), is_number(), is_binary()}. I want
to define a guard to match it. Without reusing I can write a function
accepting it:
func({x, y, z}) when is_atom(x) and is_number(y) and
Actually, that what I understood only in my last message - I can implement
it right now. I'm pretty new to Elixir, so that wasn't obvious to me.
Currently, it seems it's resolved, there are only suggestions to improve
syntax, that are too minor.
Thank everyone for assistance
On Wed, Nov 7, 2018
Hi all
The desire for more safety in Elixir is reasonable, both at compile time
and at runtime.
The core team have previously experimented with introducting a compile time
type checking system, and we also have the dialyser and gradualizer tools
that can be used with Elixir.
Checking at runtime
Thanks for the answers. Just want to note, that I don't want to invent type
system such as in statically typed languages. I mean more about defining
schemas we can check different values with. All pattern matching, guards
and typespec might work for this. Furthermore, it would be cool to make
Hi Sergiy
The functionality you've described can be implemented with macros, no need
to modify Elixir or Erlang.
To start it could be as simple as defining guards that assert nothing in
the production environment.
defmodule Test do
if Mix.env() == :prod do
defguard is_my_type(x) when true
Hi Sergiy
I'm afraid I don't follow. From what I understand of your proposal the
current defguard system meets your needs- what are you looking to add?
Cheers,
Louis
On Wed, 7 Nov 2018 at 18:38 Sergiy Kukunin wrote:
> I afraid you missed my point, I might have expressed it poorly. Let's
>
Hey
The implementation you've given there is expensive and only works for lists
up to a certain length.
To solve this one you'll need to step outside of guard clauses as they only
support a limited subset of Elixir/Erlang. The idea is that all operations
in guards are very fast and run in
Found another problem: can't express "list of strings" in guards nor
pattern matching. It's an easy task for typespecs `[String.t(), ...]`, but
I can't check typespecs in runtime. Found a very dirty hack, that works for
lists up to 5 strings, enjoy:
defguardp is_list_of_strings(x)
when
Thanks for the explanation about guards, makes sense. And I totally agree
with you, that can be implemented as an assertion at the very begin of
function's body.
Again, the question - is there a way to leverage typespecs? Is there a way
to implement something like this "hey elixir, is this value
Hey
I don't believe that exists, at least not in the standard distribution.
Perhaps there is a library that provides this functionality.
Cheers,
Louis
On Wed, 7 Nov 2018, 23:05 Sergiy Kukunin, wrote:
> Thanks for the explanation about guards, makes sense. And I totally agree
> with you, that
I mistook, sorry: To avoid performance penalty we could enable
the typespec runtime asserts only for development and testing environments
On Wednesday, November 7, 2018 at 1:00:53 PM UTC+2, Sergiy Kukunin wrote:
>
> Hello there. This is my first message to the elixir group. Thanks for the
>
Hello there. This is my first message to the elixir group. Thanks for the
great language.
While I'm writing my code, I want to make functions to be safer. It's bad
practice if a function accepts unexpected input and pass it further, and it
blows in a completely different part of a system.
At
If you want type-safety why not to just pick a strongly typed language,
like Ocaml for example? Elixir is bound to Erlang VM and will never provide
any features like you're describing that are not supported by Erlang. And I
don't think type-checking ever happens at runtime in any language.
On
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