[erlang-questions] what does when do here? fib(1200000) so slow, erlang cant handle big numbers?

[t ty]

What would happen if you didn't have the 'when N > 0' and you call
using fib(-1) ?

2008/7/1 Circular Function <circularfunc@REDACTED>:
> what does when N>0 do here? seems like no difference.
> and would you consider this good idiomatic erlang(ofc there is an even
> faster one that i found, posted at the end)?
>