REBOL[ File: %tj-operators.r Date: 27-Dec-2006 Title: {Custom math operators} Purpose: {Math shorthand. Used by other of my library functions. Rollover operator} Author: "Tim Johnson" email: %tim--johnsons-web--com NOTE: {'++ is copied directly from the REBOL docs, '-- and '++- based on '++} Library: [ level: 'beginner platform: 'all type: [Function one-liner] domain: [math] tested-under: "Linux, CGI" support: ["Tim Johnson" %tim--johnsons-web--com] license: none see-also: none ] ] ; ----------------------------------------------------------------------------------------- div: func[ {returns [quotient remainder]} dividend[integer!] divisor[integer!] /obj {return context[quot: n rem: n]} ][ either obj[ make object! compose[ quot: (to-integer dividend / divisor) rem: (dividend // divisor) ] ][ reduce[to-integer dividend / divisor dividend // divisor] ] ] ; ----------------------------------------------------------------------------------------- ++: func[ {increments a value} 'word ] [ set word 1 + get word ] ; ----------------------------------------------------------------------------------------- --: func[ {decrements a value} 'word ] [ set word -1 + get word ] ; ----------------------------------------------------------------------------------------- ++-: func[ {increments a value. If it exceeds limiter (or length of limiter), reset to 1} 'word limiter[number! series!] /local limit][ limit: either series? limiter[length? limiter][limiter] set word 1 + get word if (get word) > limit[set word 1] ] ; ----------------------------------------------------------------------------------------- ; '++- is very useful for interating over a series and "rolling back" to the first ; element when past end. ; ----------------------------------------------------------------------------------------- comment { CONSOLE EXAMPLES FOLLOW ----------------------- >> do %operators++.r >> a: 1 == 1 >> ++ a == 2 >> -- a == 1 >> s: "abcd" == "abcd" >> loop 6[++- a s print s/:a] b c d a b c >> div 11 4 == [2 3] >> t: div/obj 11 4 >> probe t make object! [ quot: 2 rem: 3 ] }