gilbertbw
Writing a macro that defines infix operators
I am trying to write a macro to define a custom operator
defmacro infix_function(op, function) do
quote do
def (a unquote(op) b), do: unquote(function)(a, b)
end
end
But I am getting a syntax error on the def (a unquote(op) b) bit. I am not sure if there is an alternative syntax to define operators that would let this work?
As an aside, when pattern matching while writing an operator I am having to do something like this:
def ((%MyStruct{} = a) * b), do: MyStruct.mult(a, b)
Is there an alternative syntax to defining infix operators that is better suited to pattern matching?
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NobbZ
There is only a coupld of valid infix operators that you can use.
Plase see Operators reference — Elixir v1.20.2 for more information.
NobbZ
infix_function(:"+", adder/2) could be made work roughly by this, IIRC how things work:
defmodule M do
defmacro infic_function(op, fun)
quote do
def unquote(op)(a, b), do: unqote(fun)(a, b)
end
end
end
You can actually use the same trick for “simpler” pattern matching…
def unquote(:"*")(%MyStruct{} = a, b), do: # impl
Whether or not this is actually “simpler” us left to you…
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