Rebol 程式設計/設計指南/使用外殼

命令外殼是一種測試想法或快速查詢函式答案的絕佳方式。

在外殼中，你可以快速顯示有關特定函式及其引數的資訊。

此外，SOURCE 函式還能顯示其他函式的編寫方式。

>> help func
USAGE:
   FUNC spec body
DESCRIPTION:
    Defines a user function with given spec and body.
    FUNC is a function value.
ARGUMENTS:
    spec -- Help string (opt) followed by arg words (and opt type and string) (Type: block)
    body -- The body block of the function (Type: block)
(SPECIAL ATTRIBUTES)
    catch

>> source func
func: func [
   "Defines a user function with given spec and body."
   [catch]
   spec [block!] {Help string (opt) followed by arg words (and opt type and string)}
   body [block!] "The body block of the function"
][
   throw-on-error [make function! spec body]
]