And identity in mathematics: https://en.wikipedia.org/wiki/Identity_function
Allen Madsen http://www.allenmadsen.com On Tue, Jul 2, 2019 at 4:05 PM Ryan Winchester <[email protected]> wrote: > And `identity` in Scala > > docs: > https://www.scala-lang.org/api/current/scala/Predef$.html#identity[A](x:A):A > > > interesting read: > https://emilvarga.com/posts/2016/08/01/using-identity-functions > > On July 2, 2019 at 1:00:53 PM, Wiebe-Marten Wijnja ([email protected]) wrote: > > > Anyway, to move the discussion forward, can someone do a more complete > survey on what this function are called in many of the other languages? I > just want to make sure we do our due diligence before adding it to the > language. > > Haskell: id > <https://hackage.haskell.org/package/base-4.12.0.0/docs/Prelude.html#v:id> > C++: std::identity > <https://en.cppreference.com/w/cpp/utility/functional/identity> > Rust: std::convert::identity > <https://doc.rust-lang.org/nightly/std/convert/fn.identity.html> > Clojure: identity <https://clojuredocs.org/clojure.core/identity> > Ruby: Object#itself > <https://ruby-doc.org/core-2.6.3/Object.html#method-i-itself> (although > this is a bound method that returns the *receiver* rather than an unbound > function taking one parameter that returns it unchanged. It is the > closest thing we have built-in in Ruby > <https://bugs.ruby-lang.org/issues/6373>, however) > Racket (and some other Lisps): identity > <https://docs.racket-lang.org/reference/procedures.html?q=identity#%28def._%28%28lib._racket%2Ffunction..rkt%29._identity%29%29> > Python: no built-in named identity function. > JS: no built-in named identity function. > PHP: no built-in named identity function. > Kotlin: no built-in named identity function. > > > > On Tuesday, July 2, 2019 at 8:40:45 PM UTC+2, José Valim wrote: >> >> Thanks Chris, it is important that someone being counter arguments, even >> if they can be disproved. :) >> >> I definitely see how such a small function can be useful but, at the same >> time, I am not convinced about the name "identity". >> >> I found it curious that Clojure actually have an identity function >> because the definition of Identity they use when talking about values and >> change is a more complex one (and one that really stuck with me): >> >> *> By identity I mean a stable logical entity associated with a series of >> different values over time* >> >> https://clojure.org/about/state#_working_models_and_identity >> >> Of course, my interpretation above is likely uncommon and there are other >> interpretations of identity that would fit nicely. >> >> Anyway, to move the discussion forward, can someone do a more complete >> survey on what this function are called in many of the other languages? I >> just want to make sure we do our due diligence before adding it to the >> language. >> >> Thank you, >> >> *José Valim* >> www.plataformatec.com.br >> Skype: jv.ptec >> Founder and Director of R&D >> >> >> On Tue, Jul 2, 2019 at 8:25 PM Christopher Keele <[email protected]> >> wrote: >> >>> Derp, I knew that. Good point. >>> >>> On Tue, Jul 2, 2019 at 9:55 AM Michał Muskała <[email protected]> wrote: >>> >>>> Because Elixir is a lisp-2 language, variables and functions are in >>>> different "namespaces". This means you can have local variables with names >>>> of local functions without any issues, but it also means you need different >>>> syntax when you want to call a function contained in a variable. Or >>>> formulated differently - variables can't shadow functions. For example, >>>> consider: >>>> >>>> bar = &foo/0 >>>> bar.() #=> 1 >>>> bar() #=> 2 >>>> def foo(), do: 1def bar(), do: 2 >>>> >>>> Having a Kernel.id/1 function would not preclude you from using variables >>>> called id. >>>> >>>> >>>> Michał. >>>> On 2 Jul 2019, 18:41 +0200, Christopher Keele <[email protected]>, >>>> wrote: >>>> >>>> I'd cast my vote against this. The proposal seems to be: >>>> >>>> 1. Create a function named 'id' or some such >>>> 2. Put it in the Kernel namespace (so it need not be prefixed) >>>> >>>> I've been doing a lot of python lately and they have a lot of things >>>> like this, including the same 'filter' global function mentioned in this >>>> thread. >>>> >>>> Points against: >>>> >>>> 1. It'd suck to not be able to use 'id' as a variable name, and would >>>> conflict with a lot of existing code. >>>> 2. Alternative names to 'id' or namespacing it are not shorter than >>>> '&(&1)' >>>> 3. '&(&1)' is more open to change with requirements >>>> 4. Adopting 'id' within Kernel would encourage adding more utility >>>> functions to it, exacerbating 1, like the proposed 'filter' function >>>> 5. Not adopting it within the Kernel would be hard, as there's no real >>>> appropriate place for it elsewhere in standard lib, unlike Enum's 'filter' >>>> >>>> Generally it's a nice idea, but I can't think of a great way to make it >>>> work, and it'd open the floodgates to more utility functions that I've come >>>> to find grating in day-to-day python development. >>>> >>>> Just my two cents, >>>> Chris K >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "elixir-lang-core" 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/elixir-lang-core/fffd5b76-4385-40de-93bd-148f1b94bb27%40googlegroups.com >>>> <https://groups.google.com/d/msgid/elixir-lang-core/fffd5b76-4385-40de-93bd-148f1b94bb27%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>> -- >>>> You received this message because you are subscribed to a topic in the >>>> Google Groups "elixir-lang-core" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/elixir-lang-core/tB61BHYIH1s/unsubscribe >>>> . >>>> To unsubscribe from this group and all its topics, send an email to >>>> [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/elixir-lang-core/b2149582-b8ba-4759-99ac-a634f73f3243%40Spark >>>> <https://groups.google.com/d/msgid/elixir-lang-core/b2149582-b8ba-4759-99ac-a634f73f3243%40Spark?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "elixir-lang-core" 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/elixir-lang-core/CAD9kT2R41gmZXU9_YAqAdyJQDP-M37j-mgUet-okoeBzF%3DdMDA%40mail.gmail.com >>> <https://groups.google.com/d/msgid/elixir-lang-core/CAD9kT2R41gmZXU9_YAqAdyJQDP-M37j-mgUet-okoeBzF%3DdMDA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" 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/elixir-lang-core/458469ec-ac00-4155-b8f0-717e6623f820%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/458469ec-ac00-4155-b8f0-717e6623f820%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" 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/elixir-lang-core/CAKBKqKQRVE1wPbfqPVSsuiR7oBUiRTAKLqojmUtZ6-G94VohPg%40mail.gmail.com > <https://groups.google.com/d/msgid/elixir-lang-core/CAKBKqKQRVE1wPbfqPVSsuiR7oBUiRTAKLqojmUtZ6-G94VohPg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" 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/elixir-lang-core/CAK-y3CtUqEy84xBwaU942exgh0y0JKq3F9XQ__BcJRyMo0Q2Qw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
