Re: Is this unquote dangerous?
On Jul 7, 5:02 am, Mike wrote: > (not sure where my reply to Chouser et al. went, but basically I said > that I was writing a macro and I might be overdoing it. I was right!) > > Here's what I was trying to accomplish, but in functions, not macros: > > (defn slice > "Returns a lazy sequence composed of every nth item of > coll, starting from offset." > [n offset coll] > (if (= offset 0) > (take-nth n coll) > (take-nth n (drop offset coll [snip] Your slice function looks similar to the built-in partition: (defn slice [n offset coll] (apply concat (partition 1 n (drop offset coll --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
On Jul 6, 6:00 pm, Chouser wrote: > On Mon, Jul 6, 2009 at 4:18 PM, Meikel Brandmeyer wrote: > > Hi, > > > Am 06.07.2009 um 22:00 schrieb Chouser: > > >> Or if you really do need a list: > > >> (for [x [1 2 3]] (cons 'some-symbol (list x))) > > > o.O > > > *cough*(list 'some-symbol x)*cough* ;) > > Oh. Right. What he said. > > --Chouser Why not this? (map #(list 'some-symbol %1) [1 2 3]) or (map list (repeatedly (constantly 'some-symbol)) [1 2 3]) --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
(not sure where my reply to Chouser et al. went, but basically I said that I was writing a macro and I might be overdoing it. I was right!) Here's what I was trying to accomplish, but in functions, not macros: (defn slice "Returns a lazy sequence composed of every nth item of coll, starting from offset." [n offset coll] (if (= offset 0) (take-nth n coll) (take-nth n (drop offset coll (let [take-helper (fn [n slices coll] (apply interleave (map #(slice n % coll) slices)))] (defn take-slices "Returns a lazy sequence of items from coll. Items are rearranged according to non-negative indexes contained in collection slices, in blocks of size n (which defaults to (+ 1 (apply max slices)). Ex: (take-slices [3 2 1] (range 14)) -> (3 2 1 7 6 5 11 10 9) (take-slices 5 [2 0] (range 20)) -> (2 0 7 5 12 10 17 15)" ([slices coll] (take-helper (+ 1 (apply max slices)) slices coll)) ([n slices coll] (take-helper n slices coll Thanks again to everyone who replied! Mike --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
On Jul 6, 4:00 pm, Chouser wrote: > On Mon, Jul 6, 2009 at 3:47 PM, Sean Devlin wrote: > > > I think your unquote is okay. ClojureQL does something similar. > > > However, my gut says this should be in a doseq, not a for statement. > > Could be totally wrong, tough. > > I think the OP is trying to build and return a list, not > trying to execute a series of operations. If I'm right, > then 'for' is better than 'doseq'. [snip] > I can't think of any way in which it's dangerous. Is it > important to you that the symbol become fully-qualified? If > so, then what you've got is fine -- are you writing a macro? Yes, I am! I'm slowly getting my head back into lispyness by diving head-first into writing a macro. =) I'm working on something that will approximately do: (take-ordered [3 0 1 2] coll) -> (interleave (take-nth 4 (drop 3 coll)) (take-nth 4 coll) (take-nth 4 (drop 1 coll)) (take-nth 4 (drop 2 coll))) This is a "rearranging" lazy seq operation, and the vector provided for the "pick-list" is of variable length. So I'm trying to build up a variable-length list of take-nth and drop applications in the macro substitution. There probably is an easier way to do this just with a function. I looked at interleave in core.clj and was surprised to see it wasn't a macro. So I may be making a mountain out of a mole hill, but it's all part of the learning process, right? =) Thanks for the help guys... Mike --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
> > Or if you really do need a list: > > (for [x [1 2 3]] (cons 'some-symbol (list x))) > Why not (for [x [1 2 3]] (list 'some-symbol x)) ? --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
On Mon, Jul 6, 2009 at 4:18 PM, Meikel Brandmeyer wrote: > Hi, > > Am 06.07.2009 um 22:00 schrieb Chouser: > >> Or if you really do need a list: >> >> (for [x [1 2 3]] (cons 'some-symbol (list x))) > > o.O > > *cough*(list 'some-symbol x)*cough* ;) Oh. Right. What he said. --Chouser --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
Hi, Am 06.07.2009 um 22:00 schrieb Chouser: Or if you really do need a list: (for [x [1 2 3]] (cons 'some-symbol (list x))) o.O *cough*(list 'some-symbol x)*cough* ;) Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: Is this unquote dangerous?
On Mon, Jul 6, 2009 at 3:47 PM, Sean Devlin wrote: > > I think your unquote is okay. ClojureQL does something similar. > > However, my gut says this should be in a doseq, not a for statement. > Could be totally wrong, tough. I think the OP is trying to build and return a list, not trying to execute a series of operations. If I'm right, then 'for' is better than 'doseq'. > On Jul 6, 2:39 pm, Mike wrote: >> Newbie question here. Probably answered in Stu's book, but I forgot >> it at home today. >> >> is: >> >> (for [x [1 2 3]] `(some-symbol ~x)) >> >> dangerous? I mean, assuming that some-symbol is bound and all. At >> the REPL I get >> >> ((user/some-symbol 1) (user/some-symbol 2) (user/some-symbol 3)) >> >> which is what I'm interested in getting, but somehow the fact that >> "for" is a macro and I'm escaping x assuming it's there is >> disconcerting. I can't think of any way in which it's dangerous. Is it important to you that the symbol become fully-qualified? If so, then what you've got is fine -- are you writing a macro? If some-symbol is not referring to a Var, though, it's more likely you want a regular quote than a syntax quote, in which case it may be more idiomatic to build a vector: (for [x [1 2 3]] ['some-symbol x]) Or if you really do need a list: (for [x [1 2 3]] (cons 'some-symbol (list x))) --Chouser --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Re: Is this unquote dangerous?
I think your unquote is okay. ClojureQL does something similar. However, my gut says this should be in a doseq, not a for statement. Could be totally wrong, tough. My $.02 Sean On Jul 6, 2:39 pm, Mike wrote: > Newbie question here. Probably answered in Stu's book, but I forgot > it at home today. > > is: > > (for [x [1 2 3]] `(some-symbol ~x)) > > dangerous? I mean, assuming that some-symbol is bound and all. At > the REPL I get > > ((user/some-symbol 1) (user/some-symbol 2) (user/some-symbol 3)) > > which is what I'm interested in getting, but somehow the fact that > "for" is a macro and I'm escaping x assuming it's there is > disconcerting. > > Thanks for any style tips... > Mike --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Is this unquote dangerous?
Newbie question here. Probably answered in Stu's book, but I forgot it at home today. is: (for [x [1 2 3]] `(some-symbol ~x)) dangerous? I mean, assuming that some-symbol is bound and all. At the REPL I get ((user/some-symbol 1) (user/some-symbol 2) (user/some-symbol 3)) which is what I'm interested in getting, but somehow the fact that "for" is a macro and I'm escaping x assuming it's there is disconcerting. Thanks for any style tips... Mike --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
