Basic idea for a Lexer flow.. not taking into account quotes or comments

basicLexerFlow.js

// the first few dozen lines are more boilerplate that we will probably already have built-in with OCaml
// In addition, the Token prototype is really a do-nothing.  A real token prototype/datatype will be much, much cooler

Object.prototype.keys = function () {
    var keys = [];

    for (var key in this) {
        keys.push(key);
    }

    return keys;
};

Array.prototype.filter = function (item) {
    return this.reduce(
        function (previousValue, currentValue) {
            if (currentValue != item) return previousValue.concat(currentValue);
            return previousValue;
        },
        []
    );
};

function replaceAll (str, charToReplace, charToBeReplacedWith) {
    return str.split(charToReplace).join(charToBeReplacedWith);
}


var OPTIONAL_SPACE_TOKEN_WORDS_REPLACEMENTS = {
    '(': ' ( ',
    ')': ' ) ',
    '{': ' { ',
    '}': ' } ',
    '+': ' + ',
    '=': ' = ',
    // notice the hack here.  Assignment will separate these two first.  Then we can rebuild it with this
    '= =': ' == '

};

function addSpaceAroundOptional(str, optional) {
    return replaceAll(str, optional, OPTIONAL_SPACE_TOKEN_WORDS_REPLACEMENTS[optional]);
}

function addSpacesAroundAllOptionals (str) {

    var partialAssignment = function (char) {
        return addSpaceAroundOptional(str, char);
    };
    return OPTIONAL_SPACE_TOKEN_WORDS_REPLACEMENTS.keys().reduce(
        function (previousValue, currentValue) {
            return addSpaceAroundOptional(previousValue, currentValue);
        },
        str
    );
}

function Token(tokenName) {
    this.name = tokenName;
}

function tokenizeOne(tokenString) {
    // TODO
    return new Token(tokenString);
}

var program = "{print() while if int string boolean == != false true +}";

console.log(addSpacesAroundAllOptionals(program).split(' ').filter('').map(tokenizeOne));