Re: [julia-users] support for '?' suffix on functions that return boolean types.
On Tue, 2014-06-17 at 09:29, j.l.vanderz...@gmail.com wrote:
> On Monday, 16 June 2014 03:33:32 UTC+2, Jacob Quinn wrote:
>>
>> it has nice discoverability properties (tab-completion)
>>
> Oh that's an interesting one. Never consciously thought of the interaction
> between naming conventions and autocomplete functionality before.
>
>
>> isn't generally too awkward (though double s's are sometimes weird
>> `issubset` `issubtype`, and it took me a while to figure out isa() => is
>> a).
>>
>
> I take it you don't like camel case? (which makes me wonder: is there a
> consensus for the idiomatic way to label multi-word identifiers in Julia?)
http://docs.julialang.org/en/latest/manual/variables/?highlight=camelcase#stylistic-conventions
says:
- Names of variables are in lower case.
- Word separation can be indicated by underscores ('\_'), but use of
underscores is discouraged unless the name would be hard to read
otherwise.
- Names of Types begin with a capital letter and word separation is
shown with CamelCase instead of underscores.
- Names of functions and macros are in lower case, without underscores.
- Functions that modify their inputs have names that end in !. These
functions are sometimes called mutating functions or in-place
functions.
I think the general style is: try to use single-word. If using
multi-word, use one which can be read without _, if that is not possible
us _.
Re: [julia-users] support for '?' suffix on functions that return boolean types.
On Monday, 16 June 2014 03:33:32 UTC+2, Jacob Quinn wrote: > > it has nice discoverability properties (tab-completion) > Oh that's an interesting one. Never consciously thought of the interaction between naming conventions and autocomplete functionality before. > isn't generally too awkward (though double s's are sometimes weird > `issubset` `issubtype`, and it took me a while to figure out isa() => is > a). > I take it you don't like camel case? (which makes me wonder: is there a consensus for the idiomatic way to label multi-word identifiers in Julia?)
Re: [julia-users] support for '?' suffix on functions that return boolean types.
On Monday, June 16, 2014 12:39:39 PM UTC-4, Stefan Karpinski wrote: > > We already have ifelse as the ternary function. If the function form has > different evaluation rules than the operator form, then it ought to have a > different name. > Ok. I suppose it couldn't evaluate like the ternary operator. Well, just ignore the last statement about the ?() function. I was really just being a bit silly there, and it isn't relevant to the main of the conversation.
Re: [julia-users] support for '?' suffix on functions that return boolean types.
We already have ifelse as the ternary function. If the function form has different evaluation rules than the operator form, then it ought to have a different name. On Mon, Jun 16, 2014 at 12:34 PM, TR NS wrote: > > > On Sunday, June 15, 2014 9:33:32 PM UTC-4, Jacob Quinn wrote: >> >> Yeah, I feel kind of torn on this on. >> >> On the one hand, I've kind of grown used to the `is...` method naming >> convention and it has nice discoverability properties (tab-completion) and >> isn't generally too awkward (though double s's are sometimes weird >> `issubset` `issubtype`, and it took me a while to figure out isa() => is a). >> >> The syntax-hungry beast in me though loves the handiness of adding a `?` >> to boolean methods. At this point, it's probably not worth the change, and >> my main concern would be combining it with the ternary operator: >> >> result = good?(x) ? good : bad >> >> The double `?` would probably get real old real fast. >> > > As a long time Rubyist, I concur that the double `?` from ternary operator > has always been a little annoying. On the other hand the readability of > `?`-suffixed predicate methods has easily outweighed the downside of this > one usage. And in Julia at least you have a `()` in between. In Ruby you > don't even have that. Valid Ruby: > > result = good? ? good : bad > > The Julia equivalent of > > result = good?() ? good : bad > > isn't so bad. > > And if I might add a small aside, ternary as an honest to god function: > > result = ?(good?(), good, bad) > > >
Re: [julia-users] support for '?' suffix on functions that return boolean types.
On Sunday, June 15, 2014 9:33:32 PM UTC-4, Jacob Quinn wrote: > > Yeah, I feel kind of torn on this on. > > On the one hand, I've kind of grown used to the `is...` method naming > convention and it has nice discoverability properties (tab-completion) and > isn't generally too awkward (though double s's are sometimes weird > `issubset` `issubtype`, and it took me a while to figure out isa() => is a). > > The syntax-hungry beast in me though loves the handiness of adding a `?` > to boolean methods. At this point, it's probably not worth the change, and > my main concern would be combining it with the ternary operator: > > result = good?(x) ? good : bad > > The double `?` would probably get real old real fast. > As a long time Rubyist, I concur that the double `?` from ternary operator has always been a little annoying. On the other hand the readability of `?`-suffixed predicate methods has easily outweighed the downside of this one usage. And in Julia at least you have a `()` in between. In Ruby you don't even have that. Valid Ruby: result = good? ? good : bad The Julia equivalent of result = good?() ? good : bad isn't so bad. And if I might add a small aside, ternary as an honest to god function: result = ?(good?(), good, bad)
Re: [julia-users] support for '?' suffix on functions that return boolean types.
Yeah, I feel kind of torn on this on. On the one hand, I've kind of grown used to the `is...` method naming convention and it has nice discoverability properties (tab-completion) and isn't generally too awkward (though double s's are sometimes weird `issubset` `issubtype`, and it took me a while to figure out isa() => is a). The syntax-hungry beast in me though loves the handiness of adding a `?` to boolean methods. At this point, it's probably not worth the change, and my main concern would be combining it with the ternary operator: result = good?(x) ? good : bad The double `?` would probably get real old real fast. -Jacob On Thu, Jun 12, 2014 at 3:04 PM, Mike Innes wrote: > Indeed, Ruby has the ternary operator as well. > > I imagine it's unlikely to change at this point, but +1 for trailing ? > from me – just in case :) > > > On Thursday, 12 June 2014 19:30:58 UTC+1, Stefan Karpinski wrote: > >> It's definitely a surmountable thing – I'd actually be rather in favor of >> using a trailing ? instead of the is prefix for predicates. I believe Jeff >> prefers the is prefix. >> >> >> On Thu, Jun 12, 2014 at 1:53 PM, Jameson Nash wrote: >> >>> Interestingly (to me) Apples new language, Swift, uses ? as both a >>> ternary operator and a suffix for 'nullable' values, so this isn't an >>> insurmountable obstacle. >>> >>> >>> On Thursday, June 12, 2014, Steven G. Johnson >>> wrote: >>> On Thursday, June 12, 2014 1:08:37 PM UTC-4, Aerlinger wrote: > > Ruby has a useful convention where methods can end in a '?' to > indicate that it returns a boolean value. This capability would be useful > in Julia as well. Much like the bang (!) suffix on functions it might look > something like this: > > function isEven?(n::Int) > n % 2 == 2 > end > Yes, both the ! and ? suffixes are common conventions, possibly originating in Scheme. Note that if you have a ? suffix, then you don't need the "is" prefix. However, ? is already being used for the ternary operator in Julia and hence is not available for use in identifiers. Hence we instead adopt the "is" prefix convention. >>> >>
Re: [julia-users] support for '?' suffix on functions that return boolean types.
Indeed, Ruby has the ternary operator as well. I imagine it's unlikely to change at this point, but +1 for trailing ? from me – just in case :) On Thursday, 12 June 2014 19:30:58 UTC+1, Stefan Karpinski wrote: > > It's definitely a surmountable thing – I'd actually be rather in favor of > using a trailing ? instead of the is prefix for predicates. I believe Jeff > prefers the is prefix. > > > On Thu, Jun 12, 2014 at 1:53 PM, Jameson Nash > wrote: > >> Interestingly (to me) Apples new language, Swift, uses ? as both a >> ternary operator and a suffix for 'nullable' values, so this isn't an >> insurmountable obstacle. >> >> >> On Thursday, June 12, 2014, Steven G. Johnson > > wrote: >> >>> >>> >>> On Thursday, June 12, 2014 1:08:37 PM UTC-4, Aerlinger wrote: Ruby has a useful convention where methods can end in a '?' to indicate that it returns a boolean value. This capability would be useful in Julia as well. Much like the bang (!) suffix on functions it might look something like this: function isEven?(n::Int) n % 2 == 2 end >>> >>> Yes, both the ! and ? suffixes are common conventions, possibly >>> originating in Scheme. Note that if you have a ? suffix, then you don't >>> need the "is" prefix. >>> >>> However, ? is already being used for the ternary operator in Julia and >>> hence is not available for use in identifiers. Hence we instead adopt the >>> "is" prefix convention. >>> >> >
Re: [julia-users] support for '?' suffix on functions that return boolean types.
Back in the day, I believe that LISP programmers would end function names with "p", for "predicate", to indicate a boolean return value. So, (stringp foo). I recall a professor saying that they'd use "lunchp" to invite colleagues to lunch... On Thu, Jun 12, 2014 at 2:30 PM, Stefan Karpinski wrote: > It's definitely a surmountable thing – I'd actually be rather in favor of > using a trailing ? instead of the is prefix for predicates. I believe Jeff > prefers the is prefix. > > > On Thu, Jun 12, 2014 at 1:53 PM, Jameson Nash wrote: > >> Interestingly (to me) Apples new language, Swift, uses ? as both a >> ternary operator and a suffix for 'nullable' values, so this isn't an >> insurmountable obstacle. >> >> >> On Thursday, June 12, 2014, Steven G. Johnson >> wrote: >> >>> >>> >>> On Thursday, June 12, 2014 1:08:37 PM UTC-4, Aerlinger wrote: Ruby has a useful convention where methods can end in a '?' to indicate that it returns a boolean value. This capability would be useful in Julia as well. Much like the bang (!) suffix on functions it might look something like this: function isEven?(n::Int) n % 2 == 2 end >>> >>> Yes, both the ! and ? suffixes are common conventions, possibly >>> originating in Scheme. Note that if you have a ? suffix, then you don't >>> need the "is" prefix. >>> >>> However, ? is already being used for the ternary operator in Julia and >>> hence is not available for use in identifiers. Hence we instead adopt the >>> "is" prefix convention. >>> >> >
Re: [julia-users] support for '?' suffix on functions that return boolean types.
It's definitely a surmountable thing – I'd actually be rather in favor of using a trailing ? instead of the is prefix for predicates. I believe Jeff prefers the is prefix. On Thu, Jun 12, 2014 at 1:53 PM, Jameson Nash wrote: > Interestingly (to me) Apples new language, Swift, uses ? as both a ternary > operator and a suffix for 'nullable' values, so this isn't an > insurmountable obstacle. > > > On Thursday, June 12, 2014, Steven G. Johnson > wrote: > >> >> >> On Thursday, June 12, 2014 1:08:37 PM UTC-4, Aerlinger wrote: >>> >>> Ruby has a useful convention where methods can end in a '?' to indicate >>> that it returns a boolean value. This capability would be useful in Julia >>> as well. Much like the bang (!) suffix on functions it might look something >>> like this: >>> >>> function isEven?(n::Int) >>> n % 2 == 2 >>> end >>> >> >> Yes, both the ! and ? suffixes are common conventions, possibly >> originating in Scheme. Note that if you have a ? suffix, then you don't >> need the "is" prefix. >> >> However, ? is already being used for the ternary operator in Julia and >> hence is not available for use in identifiers. Hence we instead adopt the >> "is" prefix convention. >> >
Re: [julia-users] support for '?' suffix on functions that return boolean types.
Interestingly (to me) Apples new language, Swift, uses ? as both a ternary operator and a suffix for 'nullable' values, so this isn't an insurmountable obstacle. On Thursday, June 12, 2014, Steven G. Johnson wrote: > > > On Thursday, June 12, 2014 1:08:37 PM UTC-4, Aerlinger wrote: >> >> Ruby has a useful convention where methods can end in a '?' to indicate >> that it returns a boolean value. This capability would be useful in Julia >> as well. Much like the bang (!) suffix on functions it might look something >> like this: >> >> function isEven?(n::Int) >> n % 2 == 2 >> end >> > > Yes, both the ! and ? suffixes are common conventions, possibly > originating in Scheme. Note that if you have a ? suffix, then you don't > need the "is" prefix. > > However, ? is already being used for the ternary operator in Julia and > hence is not available for use in identifiers. Hence we instead adopt the > "is" prefix convention. >
Re: [julia-users] support for '?' suffix on functions that return boolean types.
This has been discussed previously, either on julia-dev or in github/issues. --Tim On Thursday, June 12, 2014 10:08:37 AM Aerlinger wrote: > Ruby has a useful convention where methods can end in a '?' to indicate > that it returns a boolean value. This capability would be useful in Julia > as well. Much like the bang (!) suffix on functions it might look something > like this: > > function isEven?(n::Int) > n % 2 == 2 > end > > > isEven?(4) # => true
