Paul Graham's "On Lisp" has a nice little section on anaphoric macros.
It has a few nice tricks, but generally the Clojure style tends to
avoid them if possible. ie. using if-let instead of an anaphoric-if
macro.
Also, I think the book Rob was referring to is called "Let Over
Lambda" by Hoyte. As
Sometimes it is useful to have a referentially opaque symbol that you can
refer to when calling a macro. Clojure's design encourages the idiom of let
bindings instead of anaphora to maintain referential transparency, but in
some cases it is preferable to capture a symbol and make use of it. If yo
On Tuesday, April 12, 2011 9:25:25 AM UTC-4, rob wrote:
>
> One Scheme advocate I know has that suggested that it would be more
> hygienic to have gensyms be the rule instead of the exception to the rule
> (you could still get capture by asking to *not* gensym). I'm not certain I
> agree with
Clojure's automatic gensym feature in defmacro is similar to the idea
suggested in Hoyte's Common Lisp book "Let Them Eat Lambda", though I gather
it's not historically originated by Hoyte as similar ideas have been
implemented by others. One Scheme advocate I know has that suggested that
it would
That's because of the order of the definitions of foobar and let.
Thus:
guik.evil=> (macroexpand '(foobar 10))
(let* [a__44__auto__ 10] (clojure.core/+ a__44__auto__ a__44__auto__))
But defining let before foobar:
guik.evil=> (macroexpand-1 '(let))
(guik.evil/let*)
guik.evil=> (macroexpand-1 (ma
On 11 Apr 2011, at 03:50, George Rogers wrote:
;;2) Shadowing a macro does not change macros that depend on it.
(defmacro foobar [x]
`(let [a# ~x]
(+ a# a#)))
(defmacro let []
`(guik.evil/let*))
(foobar 10) ;=> 20
That's due to namespaces, which indeed solve many of the "hygiene"
probl
(ns guik.evil)
;;1) Special forms cannot be shadowed
(defmacro let* []
(+ 1 1))
;; (let*) ; would yield
;=> clojure.lang.Compiler$CompilerException:
java.lang.IllegalArgumentException: Bad binding form, expected vector
(evil.clj:6)
;;2) Shadowing a macro does not change macros that depend on it.
