在clojure函数名中使用 - 和*

Question

Every so often I run into a bit of clojure code where a function name either begins with "-" or ends with "*" and while I can make some guesses from the context, I haven't been able to find any exact definitions of what they indicate. Could someone give me a quick explanation or point me somewhere that has one?

Answer 1

Conventions for functions are...conventions. There no mandatory naming but some habits whom sometime came from lisps.

• -function is used by some programmers for private functions declared by defn-. But also
• .-function for attribute access for objects from ClojureScript.
• function? are generally boolean test function (even?, list?, ...)
• function! are functions that involve side effect.
• function name embedding -> are conversion functions.
• *var* are dynamic variables.

And a lot more from programming group conventions.

Answer 2

And the last part: foo* is often used for the underlying function of a convenience macro foo . Eg, log vs log*

Answer 3

"-" and "*" are just part of a valid Clojure symbol. They do not indicate anything special per se, and the Clojure compiler will treat them just like any other symbol.

Conventionally, *'s are used to surround the name of a dynamic var. You can make a var dynamic without the *'s, but it might cause confusion for someone dealing with your code when the value of the var unexpectedly changes out from under them due to a binding call somewhere up the stack. By including the *'s, you are reminding any users of that var that it is dynamic everytime they write/read its name.

Symbols that begin with "-" are typically used in connection with Clojure's gen-class construct. That is because "-" is the default prefix to append to method names when mapping a class's method to a function. However, there are other things it could mean as well.

As Ivan points out, there are other conventions that might be worth knowing as well. However, they're just conventions -- like camelCasing in other languages.