add stacktrace on safe, and notes on curry

async.js

@@ -73,6 +73,7 @@ function tryCatchPass (_try,_catch,_pass) {
 exports.safe = safe
 
 function safe (funx) {
+  var err = new Error((funx.name || funx.toString().slice(0,100) + '...') + ' called more than once')
   return function () {
     var _callback = arguments[arguments.length - 1]
       , n = 0
@@ -82,7 +83,8 @@ function safe (funx) {
       if(!n++)
         _callback.apply(this,args)
       else
-        console.log('callback function ' + _callback.name + ' called:' + n + ' times')
+        console.err(err.stack)
+        //console.log('callback function ' + _callback.name + ' called:' + n + ' times')
     }
     try {
       funx.apply(null, arguments)
@@ -118,9 +120,9 @@ exports.timeout = function (func, time) {
                   checker(err)
                 }, time)
     function checker () {
+      clearTimeout(timer)
       if(! called ++)
         callback.apply(null, [].slice.call(arguments))
-      clearTimeout(timer)
     }
     args.push(checker)
     return func.apply(this, args)

functions.js

@@ -2,7 +2,43 @@ var objects = require('./objects')
 exports.id = function (i) {
   return i
 }
+/*
+often you want to do something like: map(array, JSON.stringify)
+but map calls the iterator with (value, key, object)
+which confuses JSON.stringify because it expects a replacer function as the second arg
+previously one would do something like this:
 
+    map(array, function (x) {return JSON.stringify(x)})
+
+TOO LONG, I can't be bothered!
+
+now use:
+
+    map(array, curry(JSON.stringify, 0))
+
+the `0` that thu first arg is in the first position.
+
+non numbers are literal, also, negative numbers count from the end of the array 
+(handy for ensuring that callbacks are in the right place)
+
+curry(func, 0)                 // function (a) { return func(a) }
+curry(func, 0, 'whatever')     // function (a) { return func(a, 'whatever') }
+curry(func, 0, 'whatever', -1) // function (a, b) { return func(a, 'whatever', b) }
+
+of course, you cannot use this function to stick in numbers, but what are you, an accountant?
+
+it's really handy though, when you can simplify this:
+
+    ctrl.toAsync(function (ls) {
+        return d.map(ls, function (e) { return path.join(dir, e) } )
+      }) ]) (dir, cb)
+
+to this:
+
+    ctrl.toAsync(d.curry(d.map, 0, d.curry(path.join, dir, 0) ))
+
+*/
+
 exports.curry = function (/*funx, args...*/) {
   var args = [].slice.call(arguments)
     , funx = args.shift()