I'm trying to do something like this:
-module(count).
-export([main/0]).
sum(X, Sum) -> X + Sum.
main() ->
lists:foldl(sum, 0, [1,2,3,4,5]).but see a warning and code fails:
function sum/2 is unusedHow to fix the code?
NB: this is just a sample which illustrates problem, so there is no reason to propose solution which uses fun -expression.
1条答案
按热度按时间ckocjqey1#
Erlang has slightly more explicit syntax for that:
See also " Learn you some Erlang ":
If function names are written without a parameter list then those names are interpreted as atoms, and atoms can not be functions, so the call fails.
...
This is why a new notation has to be added to the language in order to let you pass functions from outside a module. This is what fun Module:Function/Arity is: it tells the VM to use that specific function, and then bind it to a variable.