当函数调用的括号不可以省略时 When Function Parentheses Are Not Optional

## 问题 Problem 你想调用一个无参数的函数，但是你不想使用括号。 You want to call a function that takes no arguments, but don’t want to use parentheses. ## 方法 Solution 不管怎样，都是用括号。 Use parentheses anyway. 另外一种方案：利用do标记法，例如： Another alternative is to utilize the do-notation like so: ~~~ notify = -> alert "Hello, user!" do notify if condition ~~~ 编译成JavaScript如下： This compiles to the following JavaScript: ~~~ var notify; notify = function() { return alert("Hello, user!"); }; if (condition) { notify(); } ~~~ ## 讨论 Discussion 和Ruby一样，CoffeeScript允许你在调用方法时不使用括号。然后，CoffeeScript会把纯粹的函数名当作指向这个函数的指针。这样实际会导致这样的结果——你没有给方法传递函数，CoffeeScript就无法分辨出你想调用这个函数还是把它当作一个引用使用。 Like Ruby, CoffeeScript allows you to drop parentheses to method calls. Unlike Ruby, however, CoffeeScript treats a bare function name as the pointer to the function. The practical upshot of this is that if you give no arguments to a method, CoffeeScript cannot tell if you want to call the function or use it as a reference. 谁优谁劣？我这并没有好坏之分，就只是不一样。这产生了一个与预期不一样的语法特例——括号不_总是_可选的——但是作为回报，它给予了使用名字平凡传递或者接受一个函数的能力，这样看Ruby就有点不给力了。 Is this good or bad? It’s just different. It creates an unexpected syntax case – parentheses aren’t _always_ optional – but in exchange it gives you the ability to pass and receive functions fluently by name, something that’s a bit klunky in Ruby. 这种do记法对于那些使用CoffeeScript但有括号恐惧症的人来说是一种优雅的方式。尽管如此，有些人还是喜欢在调用函数时把括号写上。 This usage of the do-notation is a neat approach for CoffeeScript with parenphobia. Some people simply prefer to write out the parentheses in the function call, though.