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How to determine the name of a variable in a piece of code

I am trying to write a halstead complexity measure in X ++ (language not important) and I think the best way to do this is to use regex in source.

I've managed to do 90% of this, but I'm struggling with variable names.

How to determine the name of a variable in a piece of code.

Considering the following piece of code

public void main()
{
    int a, b, c, av;
    className class;
    strFmt("%1 %2 %3", a, b, c);
    av = (a + b + c) / 3;
    info("avg = %1");*/

    if(a)
    {
        a++;
        class.add(a);
    }
    else
    {
        b++;
        class.subtract(b)
    }

    this.main();
}

I expect to return "a" "b" "c" "av" "class"

With halstead, he needs to count their copies. The way I thought it was to store the above in a list and then use whatever is in the list in the regex query. Service for all possible uses of the variable would be insane.

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6 answers


I ended up cheating the solution. I already had all the operator data like int / public / methods etc., so I just used substituion in the source and then ran the following regex which found the operands for the metric for me.

'_?\w+(?=([^"]*"[^"]*")*[^"]*$)|".+"'

There were some really good answers here, so I'm going to look into a hybrid of them to improve the implementation at a later date, but while we get the information we need and seem to work in all cases, we've tested it.

In case anyone is interested, the regex I used for operators is the following



(?i)\(|\{|\w+(?=(\(|:|\.))|\w+(?=\s\w)|(break|continue|return|true|false|retry|asc|breakpoint|desc|null|pause|throw|ttsAbort|ttsBegin|ttsCommit)(?=;)|((try|catch|else|by|do)(?=\n))|(\+=|-=|>=|<=|==|!=|=|\+\+|--|<<|>>|&&|\|\||\*|\/|\+|-|~|&|\^|\||>|<|!|\?|::|:|\.)+(?=([^"]*"[^"]*")*[^"]*$)

It has all the reserved keywords that are not covered by the first 4 operators, I also got a list of operators that use x ++.

This will require some modification that will be used in other languages, but given that other languages ​​have better ways of solving these problems, you probably don't need to.

Thanks for all your answers

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I think you will need to think about AOT to get different variables.

You can use using reflection TreeNode

, or perhaps you could use XPPCompiler to get information about the objects you are processing to help:



info(strFmt("%1", new xppCompiler().dumpClass('salesformletter')));

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This question got me curious about how to do it and I came across this great post which has a dedicated AX tool for measuring difficulty as well as a 175 page engraving written about it.

http://bojanjovicic.com/complexity-tool-dynamics-ax-2009/

I'm experimenting with this now and seeing how I can pounce on it.

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I came back with a real answer! Use the object SysScannerClass

and TreeNode

for the proper analysis of the code. Here is a lovely sample I wrote that should make his cake.

static void JobParseSourceCode(Args _args)
{
    TreeNode        treeNode = TreeNode::findNode(@'\Data Dictionary\Tables\SalesTable\Methods\find');
    SysScannerClass sysScannerClass = new SysScannerClass(treeNode);
    int             symbol;
    int             curLine;
    str             lineStr;  

    setPrefix("Scanning " + treeNode.treeNodePath());
    for (symbol = sysScannerClass.firstSymbol(); symbol; symbol = sysScannerClass.nextSymbol())
    {
        if (curLine != sysScannerClass.line())
        {
            curLine = sysScannerClass.line();
            lineStr = sysScannerClass.sourceLine(curLine);
        }

        // NOTE: symbol corresponds to macros in #TokenTypes
        info(strFmt("Line %1: %2\t(Col %3): '%4' - MacroValue: %5, [%6]", curLine, lineStr, sysScannerClass.col(), sysScannerClass.strValue(), symbol, xppScanner::symbolClass(symbol)));
    }
}
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Well, the example doesn't quite qualify as an X ++ source because it class

is a reserved word and cannot be used for a variable name.

Also, a rough search [a-zA-Z_][a-zA-Z_0-9]+

will give you all the strings that could be a variable name. But without a complete parser, it will be difficult for you to determine if it is a keyword, class name, table name, etc. Or the name of a genuine variable.

You can also use TextBuffer

to tokenize your source :

static void TokenTest(Args _args)
{
    str src = @'
        public void main()
        {
            int a = 7, b = 11, c = 13, av;
            info(strFmt("%1 %2 %3", a, b, c));
            av = (a + b + c) / 3;
            info(strFmt("avg = %1"));
            this.main();
        }    
    ';
    TextBuffer t = new TextBuffer();
    t.ignoreCase(true);
    t.setText(src); // Set the text to break in to tokens
    while (t.nextToken(false,' (){}.,:;!=+-*/\n')) // The delimiters to search 
    {
        info(t.token());
    }
}

This won't work with lines and comments, of course.

There is even an undocumented core class called Keywords !

Perhaps the best option would be to integrate with the cross-referencing tool , it did the splitting for you!

I'm afraid your remaining 10% might take 90% of your time!

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You can use regex101.com to play with regex. I think you can play with lookups (?=...)

and groups (?<=...)

:

This regex will match all your variables:

/(?!void)(?<=[ \(])[a-z]+(?=[, ;+*\/\)])/

And here's the proof:

http://regex101.com/r/hS9dQ6/2

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