We can match arguments like this in elixir: iex(1)> f = fn(a, [b: a]) -> a end #Function<12.99386804/2 in :erl_eval.expr/5> iex(2)> f.(:me, b: :me) :me iex(3)> f.(:me, a: :me) ** (FunctionClauseError) We can even mat…

[image] ijverig: Is there a way to match on keys in Maps? You can use the pin operator ^ for this. a = 1 case %{1 => :value} do %{^a => value} -> value end So f = fn(a, %{a => a}) -> a end might be “rewritten” as f = fn a, map -> case map do %{^a => ^a} -> a end end iex(2)> f.(1, %{1 =>…

It’s currently impossible to match on “variable” map keys when passed as function arguments, yes. It is possible to match on map values for predefined keys def f(%{a: a}, %{a: a}), do: true def f(_m1, _m2), do: false

Elixir Programming Language Forum

Matching argument and map key in function parameters

Questions & Help Questions

ijverig May 8, 2018, 5:37pm 3

Sure. Impossible to match on the parameters, then.