I've noticed that Clojure is missing several math functions that come standard with most programming languages, especially other Schemes/Lisps. Many of these functions are available in java's math library, but only for doubles.
I am attaching a file that tries to "do the right thing" for Clojure's other numeric types, for inclusion in the contribs, or possibly the core. I have sent in a contributor agreement, but am unfamiliar with the submission process. Do I just attach the file here, or is there somewhere I'm supposed to upload them? Are there standards for documenting and including test cases that I need to follow? I started with expt, because the lack of expt was the biggest nuisance for me. If you give it an exact number (i.e., not a floating point), and an integer exponent, it will give you a precise result, otherwise it calls Java's double version of pow. I posted this the other day, but it is included again here, with a couple minor tweaks. Next, I did floor, ceiling, and round. All of these functions yield an integer if the input is an exact number, otherwise they do whatever Java's double version does (Java's floor and ceiling yield doubles, and round yields an integer or the max int if out of range). round is a round-up to mimic Java's behavior (I think that in Scheme, round is usually a round-to-even, so this is a potential gotcha to be aware of). Those are the additions that I consider most essential. While I was at it, I added implementations for abs and mod, which are standard in most languages, and gcd which is standard in Scheme. Also, I added a version of sqrt that gives an exact answer whenever there is an exact answer (works on integers, decimals, and fractions), otherwise it gives you whatever Java's sqrt produces. I don't know how generally useful this is, but it's the behavior I've come to expect from working with Scheme. I hope everyone finds these functions as useful as I do. P.S. While writing these functions, I really liked working with Clojure's multimethod system, and found it very intuitive to set up functions that do the right things. For example, expressing a custom version of expt when the base is "exact" and the power is "some kind of integer type" was a snap. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
math.clj
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