Re: simple debugging utility
Hi, Am 24.03.2009 um 16:00 schrieb Mark Volkmann: Thanks! It looks like I don't need the let now. But there are reasons to keep it! Eg. returning the expression result! (defmacro dump [expr] `(let [value# ~expr] (println (pr-str (quote ~expr)) "=" (pr-str value#)) value#)) Then you can mix in your dump macro where you want. Your version always returns nil. Or you can have a look at clojure.contrib.trace. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: simple debugging utility
For reference, here's a version I wrote while I was working on cl- format and the pretty printer: (defn prerr [& args] "Println to *err*" (binding [*out* *err*] (apply println args))) (defmacro prlabel [prefix arg & more-args] "Print args to *err* in name = value format" (cons 'prerr (cons (list 'quote prefix) (mapcat #(list (list 'quote %) "=" %) (cons arg more- args) It prints a label (which is a string, but the macro quotes it for you and a set of forms you want to print. Using the above example, this would be (prlabel foo (+ 1 2)) and it would print: foo (+ 1 2) = 3 A real example from the PrettyWriter is: (prlabel tf? (.getColumn this) (buffer-length tokens)) I make sure the output goes to *err* partially because that just seems right for trace output and partially because cl-format tends to have *out* bound at its whim. Tom On Mar 24, 8:32 am, Joshua Fox wrote: > Eric Rochester has a debug macro, together with a walkthrough of how he > built it, > herehttp://writingcoding.blogspot.com/2008/09/stemming-part-19-debugging > > Joshua > > On Tue, Mar 24, 2009 at 4:43 PM, Mark Volkmann > wrote: > > > > > I want to write a function or macro that allows me to output the value > > of an expression without repeating it. For example, I want something > > like (dump (+ 1 2)) to output "(+ 1 2) = 3". > > > This works. > > > (defn dump1 [string] > > (println string "=" (load-string string))) > > (dump1 "(+ 1 2)") > > > Note how I had to put the expression passed to dump1 in quotes to make a > > string. > > > I'm wondering if there is a way to avoid that using a macro. The hard > > part is printing the expression. The following doesn't work. It > > outputs "3 = 3". > > > (defmacro dump2 [expr] > > `(let [value# ~expr] > > (pr ~expr) > > (println " =" value#))) > > (dump2 (+ 1 2)) > > > -- > > R. Mark Volkmann > > Object Computing, Inc. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: simple debugging utility
Eric Rochester has a debug macro, together with a walkthrough of how he built it, here http://writingcoding.blogspot.com/2008/09/stemming-part-19-debugging.html Joshua On Tue, Mar 24, 2009 at 4:43 PM, Mark Volkmann wrote: > > I want to write a function or macro that allows me to output the value > of an expression without repeating it. For example, I want something > like (dump (+ 1 2)) to output "(+ 1 2) = 3". > > This works. > > (defn dump1 [string] > (println string "=" (load-string string))) > (dump1 "(+ 1 2)") > > Note how I had to put the expression passed to dump1 in quotes to make a > string. > > I'm wondering if there is a way to avoid that using a macro. The hard > part is printing the expression. The following doesn't work. It > outputs "3 = 3". > > (defmacro dump2 [expr] > `(let [value# ~expr] > (pr ~expr) > (println " =" value#))) > (dump2 (+ 1 2)) > > -- > R. Mark Volkmann > Object Computing, Inc. > > > > --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: simple debugging utility
On Mar 24, 2009, at 16:00, Mark Volkmann wrote: > Thanks! It looks like I don't need the let now. Indeed. > Does a macro have to evaluate to one form? For example, this works, > but it seems I can't > drop the do. Yes, a macro has to evaluate to one form. This is actually not so much a condition on macros as a consequence of the fact that a macro, like any function, has a single return value. What else could that reasonably be but a form? Konrad. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: simple debugging utility
2009/3/24 Mark Volkmann : > > Thanks! It looks like I don't need the let now. Does a macro have to > evaluate to one form? For example, this works, but it seems I can't > drop the do. > > (defmacro dump [expr] > `(do > (print (quote ~expr)) > (println " =" ~expr))) How about: (defmacro dump [expr] `(println '~expr "=" ~expr)) > R. Mark Volkmann -- ! Lauri --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: simple debugging utility
On Tue, Mar 24, 2009 at 9:55 AM, Konrad Hinsen wrote: > > On Mar 24, 2009, at 15:44, Mark Volkmann wrote: > >> I'm wondering if there is a way to avoid that using a macro. The hard >> part is printing the expression. The following doesn't work. It >> outputs "3 = 3". >> >> (defmacro dump2 [expr] >> `(let [value# ~expr] >> (pr ~expr) >> (println " =" value#))) >> (dump2 (+ 1 2)) > > All it takes to make it work is a slight modification: > > (defmacro dump [expr] > `(let [value# ~expr] > (pr (quote ~expr)) > (println " =" value#))) > > (dump (+ 1 2)) > > prints: > > (+ 1 2) = 3 Thanks! It looks like I don't need the let now. Does a macro have to evaluate to one form? For example, this works, but it seems I can't drop the do. (defmacro dump [expr] `(do (print (quote ~expr)) (println " =" ~expr))) -- R. Mark Volkmann Object Computing, Inc. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: simple debugging utility
On Mar 24, 2009, at 15:44, Mark Volkmann wrote: > I'm wondering if there is a way to avoid that using a macro. The hard > part is printing the expression. The following doesn't work. It > outputs "3 = 3". > > (defmacro dump2 [expr] > `(let [value# ~expr] > (pr ~expr) > (println " =" value#))) > (dump2 (+ 1 2)) All it takes to make it work is a slight modification: (defmacro dump [expr] `(let [value# ~expr] (pr (quote ~expr)) (println " =" value#))) (dump (+ 1 2)) prints: (+ 1 2) = 3 Konrad. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---