tests/seq.py

tests: introduce 'seq.py' as a portable replacement for 'seq'

OS X 10.6.8 doesn't have it, while 10.10 does.  I'm not sure when it was added.
It may be missing from other platforms as well.

This currently doesn't handle the string manipulation options (-f, -s and -w in
MinGW anyway), since there is currently no need for it.  Since xrange defaults
to starting at 0 instead of 1, and treats the end as exclusive instead of
inclusive, the args need to be extracted instead of doing:

        xrange(*[int(a) for a in sys.argv[1:]])

Therefore, the step might as well be added, even though there is no current use.

#!/usr/bin/env python
#
# A portable replacement for 'seq'
#
# Usage:
#   seq STOP              [1, STOP] stepping by 1
#   seq START STOP        [START, STOP] stepping by 1
#   seq START STEP STOP   [START, STOP] stepping by STEP

import sys

start = 1
if len(sys.argv) > 2:
    start = int(sys.argv[1])

step = 1
if len(sys.argv) > 3:
    step = int(sys.argv[2])

stop = int(sys.argv[-1]) + 1

for i in xrange(start, stop, step):
    print i