Support module attributes inside << ... >>

[Mário Guimarães]

Hello,

It would be very useful if module attributes could be used when defining binary values via << ... >>, like in this example

defmodule MyModule do
  @param 8
  @bin << 0 :: @param >>
end

which fails to compile

== Compilation error in file lib/..../file.ex ==
** (CompileError) lib/..../file.ex:6: unknown bitstring specifier: Module.__get_attribute__(__MODULE__, :param, 6)
    (elixir) src/elixir_bitstring.erl:171: :elixir_bitstring.expand_specs/6
    (elixir) src/elixir_bitstring.erl:41: :elixir_bitstring.expand/8
    (elixir) src/elixir_bitstring.erl:20: :elixir_bitstring.expand/4
    (stdlib) lists.erl:1354: :lists.mapfoldl/3
    (stdlib) lists.erl:1355: :lists.mapfoldl/3
    (elixir) expanding macro: Kernel.@/1

Thanks

Mário Guimarães

[Mário Guimarães]

I discovered that it is possible to achieve the same effect this way

defmodule MyModule do
  @param 8

  param = @param
  @bin << 0 :: size(param) >>
end

so perhaps this is enough.

Thanks