4 ms·

>Well I can do runtime checks just as easily in Clojure, but I'm really talking about compile time checks. Take a look at this: http://ahungry.com/blog/2015-07

>Well I can do runtime checks just as easily in Clojure, but I'm really talking about compile time checks. Take a look at this: http://ahungry.com/blog/2015-07-10-Type-Safety-and-Lack-Thereof.html#org8c81166 http://ahungry.com/blog/2015-07-10-Type-Safety-and-Lack-Ther... It shows you a 9-lines macro for CL, that allows you to declare types in a way resembling Haskell, and having the compiler do the static checks. Very nice. Another example is here: https://news.ycombinator.com/item?id=8598149 https://news.ycombinator.com/item?id=8598149

hellofunk 9y ago
That's a neat example (the first one) but it's using compile time constants in the type check, which is not as impressive. You could write a similar macro in Clojure that does that.
- lispm 9y ago
  (declaim (ftype (function (integer string) cons) foo)) (defun foo (a b) (list a b)) (declaim (ftype (function (integer) cons) bar)) (defun bar (a) (foo a a)) (declaim (ftype (function (integer) integer) baz)) (defun baz (a) (+ (foo a "b") 42)) The SBCL compiler: in BAR: an argument of the wrong type. ; in: DEFUN BAR ; (FOO A A) ; ; note: deleting unreachable code ; ; caught WARNING: ; Derived type of A is ; (VALUES INTEGER &OPTIONAL), ; conflicting with its asserted type ; STRING. ; See also: ; The SBCL Manual, Node "Handling of Types" in BAZ: the wrong return type ; compiling (DECLAIM (FTYPE # ...)) ; compiling (DEFUN BAZ ...) ; file: /private/tmp/test.lisp ; in: DEFUN BAZ ; (+ (FOO A "b") 42) ; ; note: deleting unreachable code ; ; caught WARNING: ; Derived type of (FOO A "b") is ; (VALUES CONS &REST T), ; conflicting with its asserted type ; NUMBER. ; See also: ; The SBCL Manual, Node "Handling of Types"