For the sake of contradicting myself, in this paper Alan Bawden explains quasi-quote much better than I can.
https://eprints.kfupm.edu.sa/60346/1/60346.pdf Note the explanation towards the end of defmacro and constructs such as ',' (in clojure I believe it would be '~' ) Also note that Clojure has the added wrinkle of namespace qualification. On Aug 11, 1:31 am, Jonathan Smith <jonathansmith...@gmail.com> wrote: > On Aug 10, 3:20 pm, Dragan Djuric <draga...@gmail.com> wrote: > > > For example: > > > (defmacro creator [param] > > `(defmacro created [p] `(the code...)) ;; note the nested quote... > > how to resolve that? any examples? > > Although I wouldn't cite my own code as a necessarily *good* or easy > to understand example, I'll pimp it anyway as it is written and > already on the net... > > http://github.com/JonathanSmith/CRIB/blob/89a3f4d9c797ef6f4e4f456001f... > > A macro is exactly the same as a function, except it has special > evaluation rules. > You'll notice that in what I posted, I only use defmacro once, > everything else is a function that returns a list > > (I've found that this gives me extra flexibility later on when I want > to continue extending the macro-metaphor... (or if I happen to want to > do runtime definition of certain things, I can swap out the macro for > a function call and an 'eval')). > > You'll also notice that syntax quote qualifies every symbol that it is > passed. > Your particular example wouldn't work, because you can't define a name- > space qualified symbol. There are two ways that you could circumvent > this. > 1.) use regular old list > (list 'defmacro 'created ['p] `(code ...)) > > 2a.) Escape and quote certain things: > > `(defmacro ~'created [p#] `(code goes here..)) > > or > > 2b.) `(defmacro ~'created [p#] ~(fn-that-returns-your-code p# and > probably some args and stuff)) > > or > > 2c.) > (let [fn-that-generates-expansion > (code-to-generate-a-fn-that-generates-an-expansion)] > `(defmacro ~'created [p#] (~fn-that-generates-expansion p#))) > > You don't actually need to use nested backquote* (For anything**, > AFAIK), I tend to avoid it because I think it makes the code fairly > unreadable (yes, more unreadable than what I posted). I normally use a > helper function and pass the arguments (similar to a foo and foo-1 > function when doing recursion). > > --------------------- > * backquote == syntaxquote > > ** I think I used nested backquotes one time in common lisp for > something, but I can't remember *why* it was necessary, in particular. > I think it is the case where you want to pass a symbol from one macro- > environment to the next, say generating a bunch of accessors... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
