gash/gash/environment.scm

108 lines
3.7 KiB
Scheme

;;; Gash --- Guile As SHell
;;; Copyright © 2018 R.E.W. van Beusekom <rutger.van.beusekom@gmail.com>
;;; Copyright © 2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of Gash.
;;;
;;; Gash is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Gash is distributed in the hope that it will be useful, but WITHOUT ANY
;;; WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
;;; FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
;;; details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Gash. If not, see <http://www.gnu.org/licenses/>.
(define-module (gash environment)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (ice-9 match)
#:use-module (gash io)
#:export (
%command-line
%functions
%global-variables
assignment
function
set-shell-opt!
shell-opt?
variable
variable-and
variable-or
))
(define %command-line (make-parameter (command-line)))
;; FIXME: export/env vs set
(define %global-variables
(map identity ;; FIXME: make mutable
`(,(cons "SHELL" (car (command-line)))
,(cons "SHELLOPTS" "")
,(cons "PIPESTATUS" "([0]=\"0\"")
,(cons "?" "0")
,@(map (lambda (key-value)
(let* ((key-value (string-split key-value #\=))
(key (car key-value))
(value (cadr key-value)))
(cons key value)))
(environ)))))
(define %functions '())
(define* (assignment name #:optional value)
(let ((value (match value
((? string?) value)
(((? string?) ...) (apply string-append value))
(#f ""))))
(set! %global-variables
(assoc-set! %global-variables name value))
#t))
(define* (variable name #:optional (default ""))
(cond ((string->number name)
=>
(lambda (n)
(if (< n (length (%command-line))) (list-ref (%command-line) n)
"")))
((equal? name "@")
(if (pair? (cdr (%command-line))) (cdr (%command-line))
""))
((equal? name "#")
(number->string (length (cdr (%command-line)))))
(else
(or (assoc-ref %global-variables name)
(if (shell-opt? "nounset") (begin
;; TODO: throw/error
(format (current-error-port) "gash: ~a: unbound variable\n" name)
#f)
default)))))
(define (variable-or name . default)
(variable name (apply string-append default)))
(define (variable-and name . default)
(let ((value (variable name #f)))
(if value (apply string-append default) "")))
(define (set-shell-opt! name set?)
(let* ((shell-opts (variable "SHELLOPTS"))
(options (if (string-null? shell-opts) '()
(string-split shell-opts #\:)))
(new-options (if set? (delete-duplicates (sort (cons name options) string<))
(filter (negate (cut equal? <> name)) options)))
(new-shell-opts (string-join new-options ":")))
(assignment "SHELLOPTS" new-shell-opts)))
(define (shell-opt? name)
(member name (string-split (assoc-ref %global-variables "SHELLOPTS") #\:)))
(define (function name body)
(set! %functions
(assoc-set! %functions name body)))