Translate haml file according to bemto concept

gistfile1.js

#!/usr/bin/env node

/**
* Прототип прототипа, точно работать должен только на тестовом примере
* из поста. Для дальнейшей доработки нужно будет ближе ознакомиться со
* спецификацией haml и формализовать правила по трансляции имен классов =)
* 
* .b-bl1
*     .b-bl2_foo
*         .__el
*         .____el_bar
*/


var fs = require( 'fs' ),
    fname = process.argv[2] || die( "specify file name to parse" );

var data = fs.readFileSync( fname, "utf-8" ),
    indent = '    ', // 4 spaces, hardcoded
    indentLength = indent.length,
    indentRegex = /^(    )+/,
    classStack = [],
    classRegex = /\.([a-z0-9_-]+)/i,
    lastIndent = -1,
    currentIndent = -1,
    currentClass = '',
    lines = data.replace( /\r\n/g, '\n' ).replace( '\r', '' ).split( '\n' );

function calcIndent( line ) {
    var match = indentRegex.exec( line );
    if( !match ) { return 0 }

    return match[0].length / indentLength;
}

function extractClass( line ) {
    var match = classRegex.exec( line );
    if( !match ) { return '' }

    return match[1];
}

function die( message, number ) {
    console.log( ( number ? "line " + number + ": " : "" ) + message );
    process.exit();
}

function processLine( line, number ) {
    currentIndent = calcIndent( line );
    currentClass = extractClass( line );

    var resultLine = line;

    if( currentIndent > lastIndent  &&  currentIndent - lastIndent > 1 ) {
        die( "too big indent jump", number )
    } else {
        classStack.length = currentIndent;
    }

    lastIndent = currentIndent;
    //console.log( line );
    //console.log( currentIndent, currentClass, classStack[ classStack.length - 2 ] || "none" );

    var match, replaceClass, levelCount;
    if( match = /^(__)+/.exec( currentClass ) ) {
        levelCount = match[0].length / 2;
        replaceClass = classStack[ classStack.length - levelCount ] ;
        if( !replaceClass ) { die( "there is no parent class " + levelCount + " level(s) higher", number ); }

        replaceClass += currentClass.replace( /^(__)+/, '__' );

        if( match = /[^_](_[0-9a-z-]+)$/i.exec( replaceClass ) ) {
            replaceClass = replaceClass.replace( match[1], '' ) + '.' + replaceClass;
        }

        resultLine = resultLine.replace( currentClass, replaceClass );
    } else {
        if( ( match = /^b-[^_]+/.exec( currentClass ) ) && match[0].length < currentClass.length ) {
            resultLine = resultLine.replace( currentClass, match[0] + '.' + currentClass );
            currentClass = match[0];
        }
    }

    classStack.push( currentClass );
    return resultLine;
}

//console.log( 'Input data: ');
//console.log( lines.join( '\n' ) );


for( var i = 0; i < lines.length; ++i ) {
    lines[ i ] = processLine( lines[ i ], i + 1 );
}

//console.log( 'Results: ');
console.log( lines.join( '\n' ) );