Further insights here: http://aplwiki.com/Left,%20Right,%20or%20the%20Same%3F
BTW, note that ISO APL conjugate returns DOMAIN ERROR for a non-numeric argument. When Dyalog introduced the identity function, they deprecated use of + as identity; perhaps they're attempting to move closer to standards conformance in this case. On Tue, Jul 1, 2014 at 9:56 AM, Elias Mårtenson <loke...@gmail.com> wrote: > Exactly, and since an identity function is useful it makes sense to map it > to the same symbol as Dyalog. > > Regards, > Elias > > > On 2 July 2014 00:55, David Lamkins <da...@lamkins.net> wrote: > >> Digging further, it's interesting to note that ISO APL defines + as >> conjugate, but does not have a binding for the identity function. >> >> >> On Tue, Jul 1, 2014 at 9:42 AM, David Lamkins <da...@lamkins.net> wrote: >> >>> I looked this up yesterday. Dialog version 13 introduced the use of the >>> tack as identity and repurposed + as conjugate. (Actually, they bound both >>> left and right tacks identically, even though they call left tack "same" >>> and right tack "identity".) If the argument of conjugate is imaginary, >>> conjugate returns the number with the imaginary part negated. If the >>> argument of conjugate is real or non-numeric, conjugate returns the >>> argument unchanged. >>> >>> >>> >>> >>> From: Juergen Sauermann <juergen.sauerm...@t-online.de> >>> >>>> To: "Elias Mårtenson" <loke...@gmail.com> >>>> Cc: "bug-apl@gnu.org" <bug-apl@gnu.org> >>>> Date: Tue, 01 Jul 2014 17:04:24 +0200 >>>> Subject: Re: [Bug-apl] Identify function >>>> Hi Elias, >>>> >>>> I looked in "Mastering APL" from Dyalog and could not find it. >>>> They call + the identity function. >>>> >>>> And what would be the use of it? >>>> >>>> /// Jürgen >>>> >>>> >>> -- >>> "The secret to creativity is knowing how to hide your sources." >>> Albert Einstein >>> >>> >>> http://soundcloud.com/davidlamkins >>> http://reverbnation.com/lamkins >>> http://reverbnation.com/lcw >>> http://lamkins-guitar.com/ >>> http://lamkins.net/ >>> http://successful-lisp.com/ >>> >> >> >> >> -- >> "The secret to creativity is knowing how to hide your sources." >> Albert Einstein >> >> >> http://soundcloud.com/davidlamkins >> http://reverbnation.com/lamkins >> http://reverbnation.com/lcw >> http://lamkins-guitar.com/ >> http://lamkins.net/ >> http://successful-lisp.com/ >> > > -- "The secret to creativity is knowing how to hide your sources." Albert Einstein http://soundcloud.com/davidlamkins http://reverbnation.com/lamkins http://reverbnation.com/lcw http://lamkins-guitar.com/ http://lamkins.net/ http://successful-lisp.com/
