(function (tree) {

tree.Alpha = function (val) {

this.value = val;

}; tree.Alpha.prototype = {

type: "Alpha",
accept: function (visitor) {
    this.value = visitor.visit(this.value);
},
eval: function (env) {
    if (this.value.eval) { return new tree.Alpha(this.value.eval(env)); }
    return this;
},
genCSS: function (env, output) {
    output.add("alpha(opacity=");

    if (this.value.genCSS) {
        this.value.genCSS(env, output);
    } else {
        output.add(this.value);
    }

    output.add(")");
},
toCSS: tree.toCSS

};

})(require('../tree'));