#!/usr/bin/env escript
%% -*- erlang -*-
%%! -smp enable -sname fibonacci debug verbose

%% I've written this as an escript rather than something that we need to compile
%% This means it will compile on the fly and execute the function named main
main([]) ->
	%% Getting the input here is simple a single call to an io function
	Num = io:get_line("\nHow many numbers of the sequence would you like?\n"),
	%% Erlang does have types - we need to remove the newline and convert the
	%% input to an integer here before passing it to the fibonacci function
	fibonacci(0, 1, list_to_integer(string:strip(Num, both, $\n)), 0);
main([Num]) ->
	fibonacci(0, 1, list_to_integer(string:strip(Num, both, $\n)), 0).


%% Here we see the elegance of erlang's tail recursion and multiple function
%% definitions. Rather than changing variables (which we can't do anyway - 
%% they are immutable!), we call the function again with new values. When
%% the end is reached ( Num == Count ), we exit with ok. Notice that the end
%% clause is first so it is exectued when the 3rd and 4th arguments match.
fibonacci( _, _, Count, Count ) ->
	ok;
fibonacci( A, B, Num, Count ) ->
	io:format("~w~n", [A]),
	fibonacci( B, A + B, Num, Count + 1).