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58 lines
1.5 KiB
Scheme
Executable file
58 lines
1.5 KiB
Scheme
Executable file
#! /usr/local/bin/guile -s
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!#
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;;; Commentary:
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;;; This is the famous Hello-World-program, written for Guile. It is a
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;;; little bit enhanced in that it understands the command line options
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;;; `--help' (-h) and `--version' (-v), which print a short usage
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;;; decription or version information, respectively.
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;;; Author: Martin Grabmueller
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;;; Date: 2001-05-29
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;;; Code:
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(use-modules (ice-9 getopt-long))
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;; This is the grammar for the command line synopsis we expect.
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;;
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(define command-synopsis
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'((version (single-char #\v) (value #f))
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(help (single-char #\h) (value #f))))
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;; Display version information and exit.
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;;
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(define (display-version)
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(display "hello 0.0.1\n"))
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;; Display the usage help message and exit.
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;;
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(define (display-help)
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(display "Usage: hello [options...]\n")
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(display " --help, -h Show this usage information\n")
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(display " --version, -v Show version information\n"))
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;; Interpret options, if --help or --version was given, print out the
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;; requested information and exit. Otherwise, print the famous
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;; message.
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;;
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(define (main options)
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(let ((help-wanted (option-ref options 'help #f))
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(version-wanted (option-ref options 'version #f)))
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(if (or version-wanted help-wanted)
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(begin
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(if version-wanted
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(display-version))
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(if help-wanted
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(display-help)))
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(begin
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(display "Hello, World!") (newline)))))
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;; Call the main program with parsed command line options.
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;;
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(main (getopt-long (command-line) command-synopsis))
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;; Local variables:
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;; mode: scheme
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;; End:
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