51 lines
1.6 KiB
Scheme
51 lines
1.6 KiB
Scheme
;;; Gash -- Guile As SHell
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;;; Copyright 2018 Timothy Sample <samplet@ngyro.com>
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;;;
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;;; This file is part of Gash.
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;;;
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;;; Gash is free software: you can redistribute it and/or modify
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;;; it under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation, either version 3 of the License, or
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;;; (at your option) any later version.
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;;;
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;;; Gash is distributed in the hope that it will be useful,
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;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with Gash. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gash built-ins shift)
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#:use-module (gash environment)
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#:use-module (ice-9 match)
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#:use-module (srfi srfi-1))
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;;; Commentary:
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;;;
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;;; The 'shift' utility.
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;;;
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;;; Code:
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(define (main . args)
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(match args
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(() (main "1"))
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((n-string)
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(let ((n (string->number n-string)))
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(cond
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((and n (exact? n) (>= n 0)
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(<= n (length (cdr (program-arguments)))))
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(set-program-arguments
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(cons (car (program-arguments))
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(drop (cdr (program-arguments)) n)))
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EXIT_SUCCESS)
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(else
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(format (current-error-port)
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"~a: shift: Invalid option ~s.~%"
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(car (program-arguments)) n-string)
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EXIT_FAILURE))))
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(_ (format (current-error-port)
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"~a: shift: Invalid options ~s.~%"
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(car (program-arguments)) args)
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EXIT_FAILURE)))
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