Racket command line use

cmdline.rkt

#| This script demos the use of command line library. Note the use
   of parameters, and the effort of encapsulating them in the local
   bound function variables.
|#

#lang racket

  (define [file-to-compile argv]
    (let ([verbose-mode (make-parameter #f)]
          [profiling-on (make-parameter #f)]
          [optimize-level (make-parameter 0)]
          [link-flags (make-parameter null)])
      (command-line
       #:program "compiler"
       #:argv argv
       #:once-each
       [("-v" "--verbose") "Compile with verbose messages"
                           (verbose-mode #t)]
       [("-p" "--profile") "Compile with profiling"
                           (profiling-on #t)]
       #:once-any
       [("-o" "--optimize-1") "Compile with optimization level 1"
                              (optimize-level 1)]
       ["--optimize-2"        (; show help on separate lines
                               "Compile with optimization level 2,"
                               "which includes all of level 1")
                              (optimize-level 2)]
       #:multi
       [("-l" "--link-flags") lf ; flag takes one argument
                              "Add a flag <lf> for the linker"
                              (link-flags (cons lf (link-flags)))]
       #:args (filename) ; expect one command-line argument: <filename>
       ; return the argument as a filename to compile
       `(,filename ,(verbose-mode)))))

(file-to-compile '("-v" "foo"))