define(["dojo/_base/kernel", "dojo/_base/lang", "./lambda"], function(kernel, lang, df){

// This module adds high-level functions and related constructs:
//	- object/dictionary helpers

// Defined methods:
//	- take any valid lambda argument as the functional argument
//	- skip all attributes that are present in the empty object
//		(IE and/or 3rd-party libraries).

	var empty = {};

	lang.mixin(df, {
		// object helpers
		keys: function(/*Object*/ obj){
			// summary:
			//		returns an array of all keys in the object
			var t = [];
			for(var i in obj){
				if(!(i in empty)){
					t.push(i);
				}
			}
			return	t; // Array
		},
		values: function(/*Object*/ obj){
			// summary:
			//		returns an array of all values in the object
			var t = [];
			for(var i in obj){
				if(!(i in empty)){
					t.push(obj[i]);
				}
			}
			return	t; // Array
		},
		filterIn: function(/*Object*/ obj, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary:
			//		creates new object with all attributes that pass the test
			//		implemented by the provided function.
			o = o || kernel.global; f = df.lambda(f);
			var t = {}, v, i;
			for(i in obj){
				if(!(i in empty)){
					v = obj[i];
					if(f.call(o, v, i, obj)){ t[i] = v; }
				}
			}
			return t;	// Object
		},
		forIn: function(/*Object*/ obj, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary:
			//		iterates over all object attributes.
			o = o || kernel.global; f = df.lambda(f);
			for(var i in obj){
				if(!(i in empty)){
					f.call(o, obj[i], i, obj);
				}
			}
			return o;	// Object
		},
		mapIn: function(/*Object*/ obj, /*Function|String|Array*/ f, /*Object?*/ o){
			// summary:
			//		creates new object with the results of calling
			//		a provided function on every attribute in this object.
			o = o || kernel.global; f = df.lambda(f);
			var t = {}, i;
			for(i in obj){
				if(!(i in empty)){
					t[i] = f.call(o, obj[i], i, obj);
				}
			}
			return t;	// Object
		}
	});
	
	return df;
});
