Might as well set Pi=3 while you're at it (sarcasm)
Seriously. Please don't set month=30 days. It won't end well. On Thu, Sep 19, 2019 at 8:41 AM Andrew Milner <[email protected]> wrote: > ...... or compromise, and define 'month' = 30 days in weewxese perhaps. > > > > On Thursday, 19 September 2019 17:39:47 UTC+3, Thomas Keffer wrote: >> >> I guess I'm queasy at the thought of a solution that simply does not >> raise an error. It should obey some basic laws of math. For example, >> subtracting a month, then adding it back on should yield the same date. >> This solution would not. >> >> I'm in favor of eliminating month arithmetic. It doesn't add anything. >> >> Alternatively, we could leave it in, but require the user to catch any >> exceptions, then make up his/her mind what the semantics should be. >> >> -tk >> >> On Thu, Sep 19, 2019 at 6:25 AM mph <[email protected]> wrote: >> >>> Hi all, >>> >>> the primary requirement is: „Do not generate errors on month_delta >>> mathematics“ >>> >>> The implementation and thus resulting date is not so important, I think. >>> >>> So if we will implement any error-free logic, then everything will be ok. >>> >>> >>> >>> In my opinion, if the user has date say Mar 10th, or 03/10 and wants to >>> subtract one month, it just wants to do MM=03-1 -> 02/10. If the formula >>> generates invalid date (03/31 -> 02/31) then we should offer a valid date, >>> e.g. 02/28. Nothing more special. >>> For general use the implementation of any existing logic (bash) should >>> be acceptable. >>> >>> Thank you >>> >>> Pavel >>> >>> >>> Dne čtvrtek 19. září 2019 15:00:20 UTC+2 Thomas Keffer napsal(a): >>>> >>>> On Wed, Sep 18, 2019 at 11:37 PM gjr80 <[email protected]> wrote: >>>> >>>>> That aside, whether you call it a bug or not I don't think we should >>>>> have a tag that when you give it an allowed value/parameter it aborts the >>>>> template. >>>>> >>>> >>>> We don't. The tag that caused the error was user-supplied. >>>> >>>> From Graham's experiments, it looks like sqlite and bash simply >>>> subtract four weeks. The span tag can already do that, so if that's >>>> what the user wants, s/he can just specify it. >>>> >>>> As for Python, it doesn't even offer month arithmetic (at least, >>>> through class datetime.timedelta), probably for the reasons we have >>>> discovered. I'm thinking we should do the same. >>>> >>>> -tk >>>> >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "weewx-user" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/weewx-user/36ad9d07-b295-4733-b0b2-44c9437133cd%40googlegroups.com >>> <https://groups.google.com/d/msgid/weewx-user/36ad9d07-b295-4733-b0b2-44c9437133cd%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > You received this message because you are subscribed to the Google Groups > "weewx-user" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/weewx-user/9df7a851-5ec6-43c3-8231-4d6f06364a58%40googlegroups.com > <https://groups.google.com/d/msgid/weewx-user/9df7a851-5ec6-43c3-8231-4d6f06364a58%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- Peter Quinn (415)794-2264 -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/CAA1SM20uCzJxyfs3DBJ6GhcgC5YAzkZ5ZahGwT0GRsHi%3DamQ%3Dg%40mail.gmail.com.
