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A very basic command-line option helper.
easy-args provides a simple way to handle command-line arguments as parameter objects.
define-arguments[syntax] (define-arguments (name [value [guard]]) ...)
define-arguments creates parameter objects for the given command line option names and sets them according to the application's command-line-arguments parameter.
For each specified argument, name should be an identifier and will be bound to the newly-created parameter object. value, if given, must be a boolean, string, or number and will be the default value of the parameter object. If no value is given, #f is used. If a procedure guard is given, it is used as the parameter object's conversion procedure.
name, when prefixed by a single dash ("-"), is used as the option's command-line flag. If name contains asterisks ("*"), they are stripped from the flag.
This form reads options from Chicken's command-line-arguments parameter internally, setting any matching arguments to the specified values and removing handled options from the list. Matched boolean arguments are set to #t; other arguments are set to the value following the matched option in the list. The return value of define-arguments is undefined.
A trivial example follows:
(use easy-args extras) (define-arguments (all-caps) (prompt "Your name? ") (exclamations 1)) (display (prompt)) (let ((message (string-join `("Hello," ,(read-line))))) (if (all-caps) (display (string-upcase message)) (display message))) (print (make-string (exclamations) #\!))
With the file above as greeter.scm:
$ csc greeter.scm $ ./greeter Your name? [Henrietta] Hello, Henrietta! $ ./greeter -all-caps Your name? [Henrietta] HELLO, HENRIETTA! $ ./greeter -prompt "Name: " -exclamations 3 Name: [Henrietta] Hello, Henrietta!!!
- 0.2 Rewrite as single form
- 0.1 Initial release
Copyright (c) 2010, Evan Hanson All rights reserved.
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