KavaScript

A quick project to bring Python-style significant whitespace to JavaScript. Works as a preprocessor.

Example:

    // comments are preserved
    cubes = closure:
        var i, len, results;
        results = []; // no matter where they are
        for (i = 0, len = list.length; i < len; i++):
            num = list[i];
            results.push(math.cube(num));
        return results;
    ;

Becomes

    // comments are preserved
    cubes = (function () {
        var i, len, results;
        results = []; // no matter where they are
        for (i = 0, len = list.length; i < len; i++) {
            num = list[i];
            results.push(math.cube(num));
        }
        return results;
    })()
    ;

Todo

This is an early alpha project.

• write command line interface
• write more tests and test infrastructure

Significant Whitespace

Brackets are added according to the indentation of each line. For indentation to be considered significant it must come four spaces at a time, and new indentations must be exactly four spaces deeper than the previous level of indentation.

Lines consisting of just whitespace and/or comments are ignored.

Lines are compared to the line of code above. If indented the same, it is a new line. If indented 4 spaces, it is the beginning of a new block. Any other level of indentation and the line is considered part of the line above it for the purposes of bracket insertion. This lets you continue a long line on the next line, as long as you avoid hitting the magic indentation level of 4 spaces.

Example: Note how the middle line is not indented four spaces more than the line above it. If it was, it would be considered the beginning of a block and a semicolon would be incorrectly inserted at the end of the first line:

    if (    (really.long.expression.goes.here === 1)
         && (another.really.long.expression.goes.here === 1) ):
        value += 1

You can still use your own brackets within a single line but don't provide your own multi-line brackets or you'll end up with double brackets.

Remember your trailing semicolons:

    var myJSON =
        name: 'joe',
        cities: ['boston',
                 'new york'] // this indent is ok because it's not
                             // four spaces in from the line above it
    ; // <-- remember this semicolon

Trailing colons

You can use a colon, Python style, to indicate that a new block is about to begin. This is optional because colons look good on most blocks (if, while, function) but not on object blocks / JSON data.

    if (value < 10):
        value += 1;

New "closure" keyword

This is experimental and likely to change.

A new keyword "closure" has been added. Use it to reduce the visual overload of "function function function" by using a different word for functions which you're just using to create a closure. It has two modes depending on the value of CLOSURE_TAILS.

When CLOSURE_TAILS is False, it is replaced with: "function ()" and its block is closed with "}"

When CLOSURE_TAILS is True, it is replaced with "(function ()" and its block is closed with "})();" In this case, you should not use the "closure" keyword to create single-line closures because they will break.