FLEX{er}

Dump Debug Method (Like var_dump Function in PHP) and Debug Class

Andrei Ionescu | 25.06.08 | 8 Comments

Although Flex Builder and Eclipse do have nice debug utilities built in, today I needed a function/method in Actionscript to display into the current application some variables’ content. So I started to implement a var_dump alike function (var_dump from PHP language).

So I started and I made the Debug class that will implement the static dump function. Looking at the PHP var_dump function I noticed two, three main problems that will appear:

data types – ex: array is displayed as object by typeof function/operator
length of objects and associative arrays – ex: length property for objects and associative arrays is undefined
behaviour of static methods and variables inside calsses – ex: a static variable will keep its content even new methods calls appear, so calling the static dump method will not reinitialize the static vars.

For al these problems solutions are available:

instead of using typeof we will use flash.utils.getQualifiedClassName static method (see also this old article) – more about typeof operator and its return values here
we will implement a method to count the first children in an object
there will be an internal recursiveDump function and a generic public dump function

Here is the application code:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 
    layout="absolute" width="500" height="400"
    creationComplete="start()">
    <mx:TextArea id="debugTA" x="10" y="10" 
        width="480" height="380"/>
    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import com.flexer.Debug;
 
            private var testdata:Object;
 
            private function start():void
            {
                // even though the object is created like here
                // the order does not reflect the order of
                // creation - the order is somehow made internally 
                testdata = new Object();
                testdata["row1"] = {
                    "col1":"a",
                    "col2":{
                        "12":"12",
                        "13":[1,2,3,4]
                    },
                    "col3":"c",
                    "col4":"d"
                };
                testdata["row2"] = new XML();
                testdata["row2"] = <test><tag1 att="att">val</tag1></test>;
                testdata["row3"] = {"col1":"a","col2":"b","col3":"c","col4":"d"};
                testdata["row4"] = {"col1":"a","col2":"b","col3":"c","col4":"d"};
                testdata["row5"] = new Array();
                testdata["row5"] = ["a","b","c","d"];
                testdata["row6"] = {"col1":"a","col2":"b","col3":"c","col4":"d"};
                // calling debug.dump
                debugTA.text = Debug.dump(testdata,3,5.5);
            }
        ]]>
    </mx:Script>
</mx:Application>

The Debug class with its static methods can be downloaded at the end but now you can see the dump of the above flex code.

Share and Enjoy:

var_dump_app

var_dump_sources

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Tags: ActionScript, class, Debug, static

This post was written by Andrei Ionescu

Views: 5830

8 Comments

On 06.25.08 TiTerm wrote these pithy words:

nice try,

you can also do ObjectUtil.toString(testdata), it will give you same result with regular lib.

On 06.26.08 Andrei Ionescu wrote these pithy words:

Thanks for comment. ObjectUtil.toString is very helpful but has some differences…

doesn’t calculate the number of children
doesn’t display all data types (XML data is not displayed)
doesn’t display the data type of the leafs
if you want to dump more than one object you have to put all your objects into an array

…but these are not major drawbacks so use ObjectUtil.toString with confidence.

On 03.05.09 Gary wrote these pithy words:

Andrei, you were very polite to TiTerm. Your dump is way more useful than ObjectUtil.toString ! The fact that it is recursive makes all the
difference for me, and the fact its not in the standard library is
negligable. Thanks heaps for this ! Exactly what I was looking for.

Gary

On 03.05.09 Andrei Ionescu wrote these pithy words:

Gary, thank you for comment. Is great to hear that the method is helpful to programmers.

On 04.20.09 alivejune wrote these pithy words:

great!

On 02.02.10 leon wrote these pithy words:

respect, I was planning to write this..but you beat me first

On 02.03.10 leon wrote these pithy words:

I made some effort to make it support XML.
This var_dump syntax is really handy to keep things uniform when displaying large structures, and share it between XML/JSON/PHP/YAML/Whatever technology.

// put these as the first lines of recursiveDump()
if (o is XML || o is XMLList)
{
    var xml:XML = (o is XML) ? o as XML : undefined;
    var xmllist:XMLList = (o is XMLList) ? o as XMLList : undefined;
    o = xml2Object((o is XML) ? xml.toString() : xmllist.toString());
}
 
internal static function xml2Object(xml:String):Object
{
    var xmlDoc:XMLDocument = new XMLDocument(xml);
    var decoder:SimpleXMLDecoder = new SimpleXMLDecoder(true);
    return decoder.decodeXML(xmlDoc);
}

On 02.03.10 Andrei Ionescu wrote these pithy words:

Leon, thanks for your piece of code. Nice approach. It is helpful but it would be great if we could get rid of those ObjectProxy displaying around the dump.

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