4 ms·

Can you add more color here? What is the separation between generics and functional programming? As an example in favor of their coupling it is very hard to wr

by bigdubs 11y ago

Can you add more color here? What is the separation between generics and functional programming? As an example in favor of their coupling it is very hard to write generalized functions for list operations without generics (without duplicating code). It is especially hard if you want to maintain type safety and don't resort to type erasure (interface{}).

nine_k 11y ago
You can do FP in Go — just not in a type-safe way. OTOH, chances are you'll still get more type safety than doing FP in Common Lisp.
- innguest 11y ago
  > OTOH, chances are you'll still get more type safety than doing FP in Common Lisp. Maybe that was the case in the past? Now there's Shen, so now you can get a lot more type safety in Common Lisp than in Go.
  - nine_k 11y ago
    Definitely Shen, Typed Scheme, and Clojure give you much more type safety than "plain" Lisp. My closest encounters with Lisp is writing elisp, which lacks all these amenities. Thus my comment.
    - karols 11y ago
      It's not entirely that bad in CL: (locally (declare (optimize (safety 3))) (defun list-int-p (list) (every #'integerp list)) (deftype list-int () `(satisfies list-int-p)) (defun xxx (list) (declare (type list-int list)) list)) It's still runtime check, but better than nothing.
      - nine_k 11y ago
        Runtime checks can be implemented anywhere — I did similar things for Python and JavaScript, as many others here did, I suppose. It's better than nothing, but it still bombs in prod, instead of giving you a static analysis error. The nice thing about static types being a core part of the language (ML, Haskell, C#,...) is that you have concise syntax and type inference at all the required spots. Otherwise (Clojure) you have to be pretty verbose, as if you were writing Java.
        rol 11y ago
        In regards to Common Lisp, depending on which implementation you use you may get some sort of type checking at compile time. For example, if you save the following code[1] into a file and try to load it into SBCL, it will give a compile time error: (ql:quickload 'defstar) (use-package 'defstar) (declaim (optimize (debug 3) (speed 0) (safety 3))) (defun* factorial ((x (integer 0 *))) ;; x is an integer from 0 up to +inf (if (zerop x) 1 (* x (factorial (1- x))))) (defun main () (factorial "foo") ;; Compile time error: "foo" conflicts with its assert type UNSIGNED-BTYE (factorial -1) ;; Compile time error: -1 conflicts with its assert type UNSIGNED-BTYE (factorial 1.0) ;; Compile time error: 1.0 conflicts with its assert type UNSIGNED-BTYE (factorial 0)) ;; Works And when you load the file into SBCL you get the following error message (assuming you have Quicklisp installed): $ sbcl --load compile-time-safety.lisp This is SBCL 1.2.7, an implementation of ANSI Common Lisp. More information about SBCL is available at <http://www.sbcl.org/>. SBCL is free software, provided as is, with absolutely no warranty. It is mostly in the public domain; some portions are provided under BSD-style licenses. See the CREDITS and COPYING files in the distribution for more information. To load "defstar": Load 1 ASDF system: defstar ; Loading "defstar" ; file: /home/rol/src/lisp/compile-time-safety.lisp ; in: DEFUN MAIN ; (FACTORIAL "foo") ; ; caught WARNING: ; Constant "foo" conflicts with its asserted type UNSIGNED-BYTE. ; See also: ; The SBCL Manual, Node "Handling of Types" ; ; compilation unit finished ; caught 1 WARNING condition It's not as nice as Haskell's type system, but it's something :) The main problem with this sort of compile-time checking is that it's implementation dependent, so some Common Lisp implementation may not provide it. You can configure the defstar library that I used on this code so that it automatically adds calls to "(check-type ...)". But then you are back at doing run-time checking of types. -- [1] - The defstar library can be found on Quicklisp or here: https://bitbucket.org/eeeickythump/defstar/ https://bitbucket.org/eeeickythump/defstar/ It's pretty much just a nicer way to write all of the "(declaim ...)" and "(declare ...)" needed to provide the most information to the Common Lisp type system.
- _yosefk 11y ago
  Well, regardless of exactly what static typing facilities CL has, at least without static type info you wouldn't need all those ugly casts.
wyager 11y ago
>What is the separation between generics and functional programming? What is the connection? There are tons of functional languages (Tulip, Racket, some Lisps) that are untyped or optionally typed. Strong types are awesome, but you don't need them for FP. Go isn't good at powerful typing or functional programming.

by bigdubs 11y ago

nine_k 11y ago

You can do FP in Go — just not in a type-safe way. OTOH, chances are you'll still get more type safety than doing FP in Common Lisp.

innguest 11y ago
> OTOH, chances are you'll still get more type safety than doing FP in Common Lisp. Maybe that was the case in the past? Now there's Shen, so now you can get a lot more type safety in Common Lisp than in Go.
- nine_k 11y ago
  Definitely Shen, Typed Scheme, and Clojure give you much more type safety than "plain" Lisp. My closest encounters with Lisp is writing elisp, which lacks all these amenities. Thus my comment.
  - karols 11y ago
    It's not entirely that bad in CL: (locally (declare (optimize (safety 3))) (defun list-int-p (list) (every #'integerp list)) (deftype list-int () `(satisfies list-int-p)) (defun xxx (list) (declare (type list-int list)) list)) It's still runtime check, but better than nothing.
    - nine_k 11y ago
      Runtime checks can be implemented anywhere — I did similar things for Python and JavaScript, as many others here did, I suppose. It's better than nothing, but it still bombs in prod, instead of giving you a static analysis error. The nice thing about static types being a core part of the language (ML, Haskell, C#,...) is that you have concise syntax and type inference at all the required spots. Otherwise (Clojure) you have to be pretty verbose, as if you were writing Java.
      - rol 11y ago
        In regards to Common Lisp, depending on which implementation you use you may get some sort of type checking at compile time. For example, if you save the following code[1] into a file and try to load it into SBCL, it will give a compile time error: (ql:quickload 'defstar) (use-package 'defstar) (declaim (optimize (debug 3) (speed 0) (safety 3))) (defun* factorial ((x (integer 0 *))) ;; x is an integer from 0 up to +inf (if (zerop x) 1 (* x (factorial (1- x))))) (defun main () (factorial "foo") ;; Compile time error: "foo" conflicts with its assert type UNSIGNED-BTYE (factorial -1) ;; Compile time error: -1 conflicts with its assert type UNSIGNED-BTYE (factorial 1.0) ;; Compile time error: 1.0 conflicts with its assert type UNSIGNED-BTYE (factorial 0)) ;; Works And when you load the file into SBCL you get the following error message (assuming you have Quicklisp installed): $ sbcl --load compile-time-safety.lisp This is SBCL 1.2.7, an implementation of ANSI Common Lisp. More information about SBCL is available at <http://www.sbcl.org/>. SBCL is free software, provided as is, with absolutely no warranty. It is mostly in the public domain; some portions are provided under BSD-style licenses. See the CREDITS and COPYING files in the distribution for more information. To load "defstar": Load 1 ASDF system: defstar ; Loading "defstar" ; file: /home/rol/src/lisp/compile-time-safety.lisp ; in: DEFUN MAIN ; (FACTORIAL "foo") ; ; caught WARNING: ; Constant "foo" conflicts with its asserted type UNSIGNED-BYTE. ; See also: ; The SBCL Manual, Node "Handling of Types" ; ; compilation unit finished ; caught 1 WARNING condition It's not as nice as Haskell's type system, but it's something :) The main problem with this sort of compile-time checking is that it's implementation dependent, so some Common Lisp implementation may not provide it. You can configure the defstar library that I used on this code so that it automatically adds calls to "(check-type ...)". But then you are back at doing run-time checking of types. -- [1] - The defstar library can be found on Quicklisp or here: https://bitbucket.org/eeeickythump/defstar/ https://bitbucket.org/eeeickythump/defstar/ It's pretty much just a nicer way to write all of the "(declaim ...)" and "(declare ...)" needed to provide the most information to the Common Lisp type system.
_yosefk 11y ago
Well, regardless of exactly what static typing facilities CL has, at least without static type info you wouldn't need all those ugly casts.

wyager 11y ago

>What is the separation between generics and functional programming? What is the connection? There are tons of functional languages (Tulip, Racket, some Lisps) that are untyped or optionally typed. Strong types are awesome, but you don't need them for FP. Go isn't good at powerful typing or functional programming.