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baldwindavid
Maxximiliann
Maxximiliann
@Qqwy, my friend, let me first start off by saying how much I absolutely love TypeCheck! I’m an Elixir noob (started learning it on my own last year with ZERO programming background) and I don’t know how I’ve gotten as far I have without it. It’s absolutely amazing!!
Your focus on generating user friendly error messages is one of its very best features! With that in mind I’d like to offer up the following suggestion: It would be very helpful if the error message were restructured to something along the lines of-
** (TypeCheck.TypeError) The call `THE_FUNCTION_EVALUATED/arity' does not adhere to spec `THE_@spec!'. Reason: parameter no. PARAMETER_NUMBER (or result) is not a 'TYPE_SPECIFIED_IN_THE_@spec!'
Details: 'COPY_OF_THE_PARAMETER_DATA_THAT_TRIGGERED_THE TypeError'.
The advantage of such a format is that it provides the most actionable information right from the jump. (My project manipulates very dense data sets so whenever there’s a TypeError I have to wade through literally pages and pages of an error report to figure out exactly what went wrong.)
2
Qqwy
TypeCheck Core Team
Interesting! Adding function/arity at the top (including its line number and filename if available) and specifying which parameter (or the result) failed before printing them might indeed be an improvement for when functions are called with arguments that are very large.
I’ll give the matter some thought 
.
4
Qqwy
TypeCheck Core Team
Version 0.3.0 has been released, which contains the improved error formatter output. (details can be found in this PR) as well as a small bugfix for types using tuple/1.
5
baldwindavid
Is there anything unique about TypeCheck that might stop me from writing a macro that generates a function with a @spec!?
I’m experimenting with a few macros for functions I write all over the place and was hoping to include specs. This example (which I import) works fine except when I add the @spec!. Is it because it is a macro in a macro?
defmacro crud_list(resource) do
quote bind_quoted: [resource: resource] do
@spec! unquote(:"list_#{resource.plural_name}")(query_pipe()) ::
list(unquote(resource.schema).t())
def unquote(:"list_#{resource.plural_name}")(queries \\ & &1) do
unquote(resource.schema)
|> queries.()
|> unquote(resource.repo).all()
end
end
end
0
Qqwy
TypeCheck Core Team
There should not be.
While TypeCheck does need to jump through some tricky hoops to make all of the syntax and semantics work and be desugared at compile-time, wrapping specs in macros is a use case which, if at all possible, I’d like TypeCheck to be able to handle properly.
If you could open an issue on GitHub that explains the code you are trying to compile and the errors you encounter, then I’ll take a look at it ASAP .
2
tcoopman
Would there be any way of integrating with TypedStruct — TypedStruct v0.3.0? Or something similar?
This would mean something like this is possible:
defmodule Example do
use TypedStruct
use TypeCheck
typedstruct module: Options do
field :name, String.t()
field :age, integer()
end
@spec! init(Example.Options.t()) :: :ok
def init(opts) do
:ok
end
end
over
defmodule Example do
use TypeCheck
defmodule Options do
defstruct [:name, :age]
@type! t :: %Options{name: binary, age: integer}
end
@spec! init(Example.Options.t()) :: :ok
def init(opts) do
:ok
end
end
3
Qqwy
TypeCheck Core Team
Qqwy
TypeCheck Core Team
Version 0.3.2 has been released.
This adds support for unquote fragments inside types and specs, so now you can use TypeCheck in metaprogramming. David’s earlier example will now compile.
Another example:
defmodule MetaExample do
use TypeCheck
people = ~w[joe robert mike]a
for name <- people do
@type! unquote(name)() :: %{name: unquote(name), coolness_level: :high}
end
end
iex> MetaExample.joe
#TypeCheck.Type< %{coolness_level: :high, name: :joe} >
iex> MetaExample.mike
#TypeCheck.Type< %{coolness_level: :high, name: :mike} >
5