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 <[email protected]> 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 <[email protected]> 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 <[email protected]> >> 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. >>> >> >
