Cameron Simpson wrote:
get_clock already has two arguments - you can optionally hand it a clock list - that's used by monotonic_clock() and hires_clock().
def get_clock(*flags, *, clocklist=None): ''' Return a Clock based on the supplied `flags`. The returned clock shall have all the requested flags. If no clock matches, return None. ''' wanted = 0 for flag in flags: wanted |= flag if clocklist is None: clocklist = ALL_CLOCKS for clock in clocklist: if clock.flags & wanted == wanted: return clock.factory() return None Would need to make *flags change to the other *_clock functions.
Have a quick glance at:
https://bitbucket.org/cameron_simpson/css/src/tip/lib/python/cs/clockutils.p...
Thanks.
The return of None is very deliberate. I _want_ user specified fallback to be concise and easy. The example:
clock = get_clock(MONOTONIC|HIRES) or get_clock(MONOTONIC)
Which would become: clock = get_clock(MONOTONIC, HIGHRES) or get_clock(MONOTONIC) +1 to returning None
Exceptions are all very well when there is just one thing to do: parse this or fail, divide this by that or fail. If fact they're the very image of "do this one thing or FAIL". They are not such a good match for do this thing or that thing or this other thing.
When you want a simple linear cascade of choices, Python's short circuiting "or" operator is a very useful thing. Having an obsession with exceptions is IMO unhealthy.
Another +1. ~Ethan~