lispy js

lispy.js

// var myfun = defun(function () {
//     // do something with/to this.args;
// });
defun = function defun() {
    var orig_func = arguments[0];
    return function() {
        // convert the arguments object into a plain old array
        var args = Array.prototype.slice.call(arguments);
        return orig_func.apply({args:args});
    }   
}

// 1 === car(1,2,3);
// 1 === car([1,2,3]);
car = defun(function() {
    if (this.args.length === 1 && typeof(this.args[0]) === typeof([])) {
        return this.args[0][0];
    }   
    else {
        return this.args[0];
    }   
});

// [2,3] === cdr(1,2,3);                                                                                                                                                              
// [2,3] === cdr([1,2,3]);
cdr = defun(function() {
    if (this.args.length === 1 && typeof(this.args[0]) === typeof([])) {
        return this.args[0].splice(1);
    }   
    else {
        return this.args.splice(1);
    }   
});

// [4,9,16] === map(function(x) { return x*x }, 2, 3, 4);
// [4,9,16] === map(function(x) { return x*x }, [2, 3, 4]);
map = defun(function() {
    var func = car(this.args);
    var args = cdr(this.args);
    var collect = []; 
    var xs; 
    if (args.length === 1 && typeof(car(args)) === typeof([])) {
        xs = car(args);
    }   
    else {
        xs = args;
    }   
    for (key in xs) {
        var x = xs[key];
        collect.push(func(x));
    }   
    return collect;
});


console.log("> car(1,2,3)");
console.log("< " + car(1,2,3));
console.log("> cdr(1,2,3)");
console.log("< " + cdr(1,2,3));
console.log("> map(function(x) { x*x }, 2,3,4)");
console.log("< " + map(function(x) {return x*x;}, 2,3,4));

console.log("\n");
console.log("> car([1,2,3])");
console.log("< " + car([1,2,3]));
console.log("> cdr([1,2,3]");
console.log("< " + cdr([1,2,3]));
console.log("> map(function(x) { x*x }, [2,3,4])");
console.log("< " + map(function(x) {return x*x;}, [2,3,4]));