3 lines
156 B
Tcl
3 lines
156 B
Tcl
proc tcl::mathfunc::fib {n} {expr {$n<-1 ? -1**($n+1) * fib(abs($n)) : $n<2 ? $n : fib($n-1) + fib($n-2)}}
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expr {fib(-5)} ;# ==> 5
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expr {fib(-6)} ;# ==> -8
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