Fibbonachi generator for the Reddit thread.

nextFib.py

#!/usr/bin/env python
import sys
import re

def prompt():
	sys.stderr.write("Preceding term: (terminate with EOF)\n")
	return sys.stdin.read()

def main():
	predecessor = int(re.sub("[^\+\-eE0-9]", "", "".join(sys.argv[1:]) if len(sys.argv) > 1 else prompt()) or 0)
	
	n = 1
	previous = 0
	current = 1
	
	while current <= predecessor:
		n += 1
		previous, current = current, previous + current
	
	if previous != predecessor:
		sys.stderr.write("Warning: Given predeccessor is not in the Fibbonachi sequence!\n")
	
	wrap = 48
	
	lead = "fib(%i) = " % n
	number = len(lead) * " " + "%i" % current
	
	string = lead + " " * (wrap - len(lead)) + number
	
	# Wrap lines to {wrap} chars, crudely.
	formatted = "\t" + "\n\t".join(string[i:i+wrap] for i in range(0, len(string) + 1, 48))
	
	print formatted

if __name__ == "__main__": sys.exit(main())