Qqwy
I stumbled across the following curious tidbit of how Elixir’s parser/compiler works:
defmodule Example do
def {} do
"Yes, this is allowed!"
end
end
iex> Example.{}
"Yes, this is allowed!"
I cannot imagine any serious use-case for this, but it is curious.
I believe the cause is that :{} is a special atom that Elixir uses in its AST-definition to describe tuples with more than two elements.
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First 3 of 3 Posts
ityonemo
henrik
Not the same, but here’s another fun one: How to "expect(…).to" in Elixir – The Pug Automatic
Qqwy
It is impossible to import the
Examplemodule in this case, however, because that will make Elixir complain that you are attempting to override one of its special forms.That said, it is possible to wrap any piece of Elixir AST in a macro that alters how the code that is passed to it is expanded. In this way you are able to alter even the behaviour of Elixir’s special forms.
One place where I’ve used this in the past is the Solution library, where the clauses of
withandcase-statements are overridden to have slightly extended support for tuples.Another is e.g. the experiment I wrote late yesterday evening which allows bare captures to exist in pipes.
@henrik Thanks for sharing that piece of code! Tuple calls are indeed a strange historic artifact.