(def +M (first [+' 1])) seems like it should work in both versions? On Oct 10, 4:28 pm, Brian Marick <mar...@exampler.com> wrote: > I may be missing something obvious. > > Midje has a checker that lets users say things like > > (fact (my-computation) => (roughly 15 2)) > > Where the first number in `roughly` is the target number and the second is an > acceptable range around that target. Part of what the checker does in 1.2 is > this: > > (<= expected (+ actual delta)) > > Now, Midje is a service. If the 1.3 user has taken care to use > promoting-to-bignum arithmetic, it would be rude to blow up if `actual` > happens to be a regular integer but adding `delta` to it causes an overflow. > I should use promoting-to-bignum addition. In Clojure 1.3, thats +'. In 1.2, > it's +. > > I can't use the token +' because it doesn't exist in 1.2: > > > java.lang.ClassCastException: clojure.lang.Symbol cannot be cast to > > java.lang.Number (NO_SOURCE_FILE:0) > > I can't use the token + because that blows up in the boundary case under 1.3 > (but not under 1.2). > > One thought is variations of code like this: > > > (if (clojure-1-3?) > > (def +M +') > > (def +M +) > > This causes amusing results because of the quote. I haven't found a variation > that works. > > So what should a library writer who wants to honor the choices of his users > do? > > ----- > Brian Marick, Artisanal Labrador > Now working athttp://path11.com > Contract programming in Ruby and Clojure > Occasional consulting on Agile
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