<div dir="ltr">I also generally think of Enum as a collection of constants so I favor CAP_WORDS for enum members. I will admit that my answer is biased in that I don't typically create Enums that have a whole bunch of methods as you've done in your example. For your example code, I might separate it out into two classes (something representing a Date and an enum representing a Holidays). The former class could use the latter to compute things like "Next business day", etc.</div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jul 18, 2016 at 8:41 AM, Guido van Rossum <span dir="ltr"><<a href="mailto:guido@python.org" target="_blank">guido@python.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Honestly my own preference would be to use UPPER_CASE, emphasizing the<br>
const-ness. CapWords is really only used for classes, which are<br>
entirely different beasts. And lower_case is for methods and<br>
variables. I think it's useful to emphasize that an enum is neither.<br>
<div class="HOEnZb"><div class="h5"><br>
On Mon, Jul 18, 2016 at 8:17 AM, Ethan Furman <<a href="mailto:ethan@stoneleaf.us">ethan@stoneleaf.us</a>> wrote:<br>
> There are currently a few locations in the stdlib, such as http and socket,<br>
> that are now using<br>
> Enums to replace constants; those names are all upper-case -- those aren't<br>
> the names I am<br>
> speaking of.<br>
><br>
> The names I am speaking of are those in brand-new enumerations where we have<br>
> full control.<br>
><br>
> As an example:<br>
><br>
> class FederalHoliday(AutoNumberEnum):<br>
> NewYear = "First day of the year.", 'absolute', JANUARY, 1<br>
> MartinLutherKingJr = "Birth of Civil Rights leader.", 'relative',<br>
> JANUARY, MONDAY, 3<br>
> President = "Birth of George Washington", 'relative', FEBRUARY, MONDAY,<br>
> 3<br>
> Memorial = "Memory of fallen soldiers", 'relative', MAY, MONDAY, 5<br>
> Independence = "Declaration of Independence", 'absolute', JULY, 4<br>
> Labor = "American Labor Movement", 'relative', SEPTEMBER, MONDAY, 1<br>
> Columbus = "Americas discovered", 'relative', OCTOBER, MONDAY, 2<br>
> Veterans = "Recognition of Armed Forces service", 'relative', NOVEMBER,<br>
> 11, 1<br>
> Thanksgiving = "Day of Thanks", 'relative', NOVEMBER, THURSDAY, 4<br>
> Christmas = "Birth of Jesus Christ", 'absolute', DECEMBER, 25<br>
><br>
> def __init__(self, doc, type, month, day, occurance=None):<br>
> self.__doc__ = doc<br>
> self.type = type<br>
> self.month = month<br>
> self.day = day<br>
> self.occurance = occurance<br>
><br>
> def date(self, year):<br>
> """<br>
> returns the observed date of the holiday for `year`<br>
> """"<br>
> ...<br>
><br>
> @classmethod<br>
> def next_business_day(cls, date, days=1):<br>
> """<br>
> Return the next `days` business day from date.<br>
> """<br>
> ...<br>
> @classmethod<br>
> def count_business_days(cls, date1, date2):<br>
> """<br>
> Return the number of business days between 'date1' and 'date2'.<br>
> """<br>
> ...<br>
> @classmethod<br>
> def year(cls, year):<br>
> """<br>
> Return a list of the actual FederalHoliday dates for `year`.<br>
> """<br>
> ...<br>
> Take the name "NewYear": if it had been a global constant I would have<br>
> named it "NEWYEAR"; if<br>
> it had been a normal class attribute I would have named it "new_year";<br>
> however, being an Enum<br>
> member, it is neither of those things.<br>
><br>
> <context switch><br>
> I've written some custom data types as part of my dbf package, and a few of<br>
> them have instances<br>
> that are singletons that are created in the global (okay, module) namespace,<br>
> and for them I<br>
> followed Python's lead in naming singletons: Python has used Title Case in<br>
> such things as None,<br>
> True, and False, so I followed suit and named mine -- Null, NullDate,<br>
> NullTime, NullDateTime, etc.<br>
> </context switch><br>
><br>
> Given my past history with using and creating singleton objects, I followed<br>
> suit when creating<br>
> my own Enum classes.<br>
><br>
> I was recently queried about my apparent break with PEP 8 for naming Enum<br>
> members, to which I<br>
> replied:<br>
><br>
>> Considering the strange beast that an Enum is, there is not much precedent<br>
>> for it anywhere.<br>
>><br>
>> Consider:<br>
>><br>
>> - Enum is a class<br>
>> - but it is a container<br>
>> - and can be iterated over<br>
>> - and it has a length (which can be zero)<br>
>> - but it's always True in a boolean sense<br>
>><br>
>> - Enum members are instances of the Enum class<br>
>> - but are pre-created<br>
>> - and new ones cannot be created<br>
>> - but are available as attributes on the class<br>
>><br>
>> Given all that I have been using Title case (or CamelCase) to name the<br>
>> members as it helps<br>
>> distinguish an Enum member from an ordinary attribute (which Enum classes<br>
>> can also have).<br>
><br>
><br>
> I forgot to include in that reply that I think CamelCase also helps to<br>
> emphasize the special<br>
> singleton nature of Enum members.<br>
><br>
> My question for the community: Your thoughts/opinions of my reasoning, and<br>
> if you don't agree<br>
> then which casing choice would you recommend and use, and why? (Reminder:<br>
> this question does<br>
> not include Enums whose names are replacements for existing constants and so<br>
> the names cannot<br>
> be changed.)<br>
><br>
> --<br>
> ~Ethan~<br>
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<br>
<br>
<br>
</div></div><span class="HOEnZb"><font color="#888888">--<br>
--Guido van Rossum (<a href="http://python.org/~guido" rel="noreferrer" target="_blank">python.org/~guido</a>)<br>
</font></span><div class="HOEnZb"><div class="h5">_______________________________________________<br>
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