Hey Chris,
Thanks for bringing that up! Before submitting this, I actually had the
syntax for multiple matches for one arm being separated by or. And frankly
I just didn't like how that looked for more than 3 items:
'1' or '2' or '3' or '4' or '5' vs '1', '2', '3', '4', '5'
But you're right. The syntax should be for tuples instead.
Here's my revised syntax, using a guard instead for the moment:
def convert_time_to_timedelta_with_match(unit:str, amount:int, now:date):
return match unit:
x if x in ('days', 'hours', 'weeks') => timedelta(**{unit: amount})
'months' => timedelta(days=30 * amount)
'years' => timedelta(days=365 * amount)
'cal_years' => now - now.replace(year=now.year - amount)
On Thursday, May 3, 2018 at 2:54:24 PM UTC-4, Chris Angelico wrote:
>
> On Fri, May 4, 2018 at 4:36 AM, Robert Roskam <raider...@gmail.com
> <javascript:>> wrote:
> > Hey Chris,
> >
> > So I started extremely generally with my syntax, but it seems like I
> should
> > provide a lot more examples of real use. Examples are hard. Here's my
> > hastily put together example from an existing piece of production code:
> >
> >
> > # New Syntax for same problem
> >
> >
> > def convert_time_to_timedelta_with_match(unit:str, amount:int,
> now:date):
> > return match unit:
> > 'days', 'hours', 'weeks' => timedelta(**{unit: amount})
> > 'months' => timedelta(days=30 * amount)
> > 'years' => timedelta(days=365 * amount)
> > 'cal_years' => now - now.replace(year=now.year - amount)
>
> Okay, here we may have a problem. You're expecting a comma separated
> set of values to indicate "any of these", but elsewhere, pattern
> matching against a list of values is making an assertion about a
> tuple. So if you have any pattern matching that isn't based on
> equality, you're going to need to clearly stipulate how your syntax
> works.
>
> If you are NOT going to support tuple pattern matching (but only
> dict), you'll need to make this VERY clear, because people are going
> to expect it.
>
> ChrisA
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