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Diffstat (limited to 'js/dojo-1.7.2/dojox/lang/functional/linrec.js')
| -rw-r--r-- | js/dojo-1.7.2/dojox/lang/functional/linrec.js | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/js/dojo-1.7.2/dojox/lang/functional/linrec.js b/js/dojo-1.7.2/dojox/lang/functional/linrec.js new file mode 100644 index 0000000..066ff54 --- /dev/null +++ b/js/dojo-1.7.2/dojox/lang/functional/linrec.js @@ -0,0 +1,147 @@ +//>>built +// wrapped by build app +define("dojox/lang/functional/linrec", ["dijit","dojo","dojox","dojo/require!dojox/lang/functional/lambda,dojox/lang/functional/util"], function(dijit,dojo,dojox){ +dojo.provide("dojox.lang.functional.linrec"); + +dojo.require("dojox.lang.functional.lambda"); +dojo.require("dojox.lang.functional.util"); + +// This module provides recursion combinators: +// - a linear recursion combinator. + +// Acknoledgements: +// - recursion combinators are inspired by Manfred von Thun's article +// "Recursion Theory and Joy" +// (http://www.latrobe.edu.au/philosophy/phimvt/joy/j05cmp.html) + +// Notes: +// - recursion combinators produce a function, which implements +// their respective recusion patterns. String lambdas are inlined, if possible. + +(function(){ + var df = dojox.lang.functional, inline = df.inlineLambda, + _x ="_x", _r_y_a = ["_r", "_y.a"]; + + df.linrec = function( + /*Function|String|Array*/ cond, + /*Function|String|Array*/ then, + /*Function|String|Array*/ before, + /*Function|String|Array*/ after){ + // summary: + // Generates a function for the linear recursion pattern. + // All parameter functions are called in the context of "this" object. + // cond: + // The lambda expression, which is used to detect the termination of recursion. + // It accepts the same parameter as the generated recursive function itself. + // This function should return "true", if the recursion should be stopped, + // and the "then" part should be executed. Otherwise the recursion will proceed. + // then: + // The lambda expression, which is called upon termination of the recursion. + // It accepts the same parameters as the generated recursive function itself. + // The returned value will be returned as the value of the generated function. + // before: + // The lambda expression, which is called before the recursive step. + // It accepts the same parameter as the generated recursive function itself. + // The returned value should be an array, which is used to call + // the generated function recursively. + // above: + // The lambda expression, which is called after the recursive step. + // It accepts two parameters: the returned value from the recursive step, and + // the original array of parameters used with all other functions. + // The returned value will be returned as the value of the generated function. + + var c, t, b, a, cs, ts, bs, as, dict1 = {}, dict2 = {}, + add2dict = function(x){ dict1[x] = 1; }; + if(typeof cond == "string"){ + cs = inline(cond, _x, add2dict); + }else{ + c = df.lambda(cond); + cs = "_c.apply(this, _x)"; + dict2["_c=_t.c"] = 1; + } + if(typeof then == "string"){ + ts = inline(then, _x, add2dict); + }else{ + t = df.lambda(then); + ts = "_t.t.apply(this, _x)"; + } + if(typeof before == "string"){ + bs = inline(before, _x, add2dict); + }else{ + b = df.lambda(before); + bs = "_b.apply(this, _x)"; + dict2["_b=_t.b"] = 1; + } + if(typeof after == "string"){ + as = inline(after, _r_y_a, add2dict); + }else{ + a = df.lambda(after); + as = "_a.call(this, _r, _y.a)"; + dict2["_a=_t.a"] = 1; + } + var locals1 = df.keys(dict1), locals2 = df.keys(dict2), + f = new Function([], "var _x=arguments,_y,_r".concat( // Function + locals1.length ? "," + locals1.join(",") : "", + locals2.length ? ",_t=_x.callee," + locals2.join(",") : t ? ",_t=_x.callee" : "", + ";for(;!", + cs, + ";_x=", + bs, + "){_y={p:_y,a:_x}}_r=", + ts, + ";for(;_y;_y=_y.p){_r=", + as, + "}return _r" + )); + if(c){ f.c = c; } + if(t){ f.t = t; } + if(b){ f.b = b; } + if(a){ f.a = a; } + return f; + }; +})(); + +/* +For documentation only: + +1) The original recursive version: + +var linrec1 = function(cond, then, before, after){ + var cond = df.lambda(cond), + then = df.lambda(then), + before = df.lambda(before), + after = df.lambda(after); + return function(){ + if(cond.apply(this, arguments)){ + return then.apply(this, arguments); + } + var args = before.apply(this, arguments); + var ret = arguments.callee.apply(this, args); + return after.call(this, ret, arguments); + }; +}; + +2) The original iterative version (before minification and inlining): + +var linrec2 = function(cond, then, before, after){ + var cond = df.lambda(cond), + then = df.lambda(then), + before = df.lambda(before), + after = df.lambda(after); + return function(){ + var args = arguments, top, ret; + // 1st part + for(; !cond.apply(this, args); args = before.apply(this, args)){ + top = {prev: top, args: args}; + } + ret = then.apply(this, args); + //2nd part + for(; top; top = top.prev){ + ret = after.call(this, ret, top.args); + } + return ret; + }; +}; + +*/ +}); |
