[erlang-questions] an erlang "gotcha"

Anthony Shipman <>
Thu Apr 5 12:38:26 CEST 2007


Is there a place where difficulties with erlang and their solutions are 
described? Perhaps another page at Trapexit.

Here's one that got me.

-module(g).
-export([run/0]).

run() ->
    Pid = spawn(fun() -> io:fwrite("spawned~n") end),
    L = [1, 2, 3],
    io:fwrite("Pid=~p L=~p~n", [Pid, L]),
    if
	is_pid(Pid) and L /= [] ->
	    io:fwrite("it worked~n");

	true ->
	    io:fwrite("it failed~n")
    end.

It prints out "it failed". If you change the 'and' to 'andalso' it works.

-- 
Anthony Shipman                    Mamas don't let your babies 
                   grow up to be outsourced.



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