(function (tree) {
tree.Expression = function (value) { this.value = value }; tree.Expression.prototype = {
eval: function (env) { if (this.value.length > 1) { return new(tree.Expression)(this.value.map(function (e) { return e.eval(env); })); } else if (this.value.length === 1) { return this.value[0].eval(env); } else { return this; } }, toCSS: function (env) { return this.value.map(function (e) { return e.toCSS ? e.toCSS(env) : ''; }).join(' '); }
};
})(require('../tree'));