you can just use (every? true? '(arg1 arg2 ....)) or def a simple function . i think the Core is powerful enough.
2013/6/11 Cedric Greevey <cgree...@gmail.com> > There's also the defmacro route: > > (defmacro if-and [test-expr binding & tests] > `(let [~binding ~test-expr] > (and ~@(concat tests [binding])))) > > Evaluates test-expr, then evaluates to the result of that if the tests all > pass, and to a falsey value otherwise (in fact, the first falsey value > returned by any of the tests). If you want only nil or the value, the and > sexp can be changed to (if (and ~@tests) binding). Short-circuits at the > first falsey test of course. Might be more convenient (fewer lambdas > needed) sometimes and more efficient sometimes -- on the other hand, to use > as a function itself it will need wrapping in a lambda: #(if-and % % > tests-using-%). > > > > On Mon, Jun 10, 2013 at 4:31 PM, Ben Wolfson <wolf...@gmail.com> wrote: > >> On Mon, Jun 10, 2013 at 1:20 PM, Steven Degutis <sbdegu...@gmail.com>wrote: >> >>> Sometimes I've wanted a function that takes a value and a bunch of >>> tests, and returns it if it passes every test, otherwise nil. >>> >>> So I wrote if-and: >>> >>> (if-and "foo" >>> >>> string? >>> #(.startsWith % "f") >>> >>> #(.contains % "oo")) >>> >>> ;; => "foo" >>> >>> >>> (if-and "foo" >>> string? >>> #(.startsWith % "f") >>> >>> #(.contains % "NOT IN THE STRING")) >>> >>> ;; => nil >>> >>> >>> Source: >>> https://github.com/evanescence/if-and/blob/master/src/if_and/core.clj >>> >>> Does this seem useful enough to put into core? >>> >>> >> "Takes a value and a bunch of tests, and returns [the value] if it passes >> every test" implies that (if-and false false?) should return false, but: >> >> user> (if-and false false?) >> nil >> >> It's also kind of confusing to me *anyway* that (if-and false false?) >> would return false and not true (to indicate that the supplied value passed >> every test). Something like this seems more intuitive to me: >> >> user> (defn allpreds [x & ts] (every? #(% x) ts)) >> #'user/allpreds >> user> (allpreds false false?) >> true >> user> (allpreds nil false?) >> false >> >> With if-and being definable in terms of allpreds: >> >> user> (defn if-and* [x & ts] (when (apply allpreds x ts) x)) >> #'user/if-and* >> user> (if-and* false false?) >> false >> user> (if-and* false nil?) >> nil >> >> -- >> Ben Wolfson >> "Human kind has used its intelligence to vary the flavour of drinks, >> which may be sweet, aromatic, fermented or spirit-based. ... Family and >> social life also offer numerous other occasions to consume drinks for >> pleasure." [Larousse, "Drink" entry] >> >> -- >> -- >> 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 >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- > -- > 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 > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- ------------------------------------**** 刘家齐 （Jacky Liu） ** 手机：15201091195 邮箱：liujiaq...@gmail.com Skype：jacky_liu_1987 QQ：406229156 -- -- 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 --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
