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       texternal-format.lisp - clic - Clic is an command line interactive client for gopher written in Common LISP
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       ---
       texternal-format.lisp (3688B)
       ---
            1 ;;;; -*- Mode: lisp; indent-tabs-mode: nil -*-
            2 ;;;
            3 ;;; external-format.lisp --- External format classes and functions.
            4 ;;;
            5 ;;; Copyright (C) 2007, Luis Oliveira  <loliveira@common-lisp.net>
            6 ;;;
            7 ;;; Permission is hereby granted, free of charge, to any person
            8 ;;; obtaining a copy of this software and associated documentation
            9 ;;; files (the "Software"), to deal in the Software without
           10 ;;; restriction, including without limitation the rights to use, copy,
           11 ;;; modify, merge, publish, distribute, sublicense, and/or sell copies
           12 ;;; of the Software, and to permit persons to whom the Software is
           13 ;;; furnished to do so, subject to the following conditions:
           14 ;;;
           15 ;;; The above copyright notice and this permission notice shall be
           16 ;;; included in all copies or substantial portions of the Software.
           17 ;;;
           18 ;;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
           19 ;;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
           20 ;;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
           21 ;;; NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
           22 ;;; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
           23 ;;; WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
           24 ;;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
           25 ;;; DEALINGS IN THE SOFTWARE.
           26 
           27 (in-package #:babel)
           28 
           29 (defvar *default-eol-style*
           30   #+windows :crlf
           31   #-windows :lf
           32   "The end-of-line style used by external formats if none is
           33 explicitly given.  Depends on the OS the code is compiled on.")
           34 
           35 (deftype eol-style ()
           36   "Possible end-of-line styles."
           37   '(member :cr :lf :crlf))
           38 
           39 (defclass external-format ()
           40   ((encoding :initarg :encoding :reader external-format-encoding
           41              :type character-encoding)
           42    (eol-style :initarg :eol-style :reader external-format-eol-style
           43               :type eol-style :initform *default-eol-style*))
           44   (:documentation
           45    "An EXTERNAL-FORMAT consists in a combination of a Babel
           46 CHARACTER-ENCODING and an end-of-line style."))
           47 
           48 (defmethod print-object ((ef external-format) stream)
           49   (print-unreadable-object (ef stream :type t :identity t)
           50     (format stream "~A ~A"
           51             (enc-name (external-format-encoding ef))
           52             (external-format-eol-style ef))))
           53 
           54 ;;; This interface is still somewhat sketchy.  The rest of Babel
           55 ;;; doesn't really understand external formats, for instance.
           56 (defun make-external-format (encoding &key (eol-style *default-eol-style*))
           57   (check-type eol-style eol-style)
           58   (make-instance 'external-format
           59                  :encoding (get-character-encoding encoding)
           60                  :eol-style eol-style))
           61 
           62 (defun ensure-external-format (thing)
           63   (etypecase thing
           64     (external-format thing)
           65     (character-encoding (make-instance 'external-format :encoding thing))
           66     (symbol (make-external-format thing))
           67     (list (apply #'make-external-format thing))))
           68 
           69 (defun external-format-equal (ef1 ef2)
           70   (and (eq (external-format-encoding ef1) (external-format-encoding ef2))
           71        (eq (external-format-eol-style ef1) (external-format-eol-style ef2))))
           72 
           73 (declaim (inline lookup-mapping))
           74 (defun lookup-mapping (ht encoding)
           75   "HT should be an hashtable created by
           76 INSTANTIATE-CONCRETE-MAPPINGS. ENCODING should be either an
           77 external format, an encoding object or a keyword symbol
           78 denoting a character encoding name or one of its aliases."
           79   (or (etypecase encoding
           80         (keyword
           81          (gethash encoding ht))
           82         (babel-encodings::concrete-mapping
           83          encoding)
           84         (character-encoding
           85          (gethash (enc-name encoding) ht))
           86         (external-format
           87          (gethash (enc-name (external-format-encoding encoding)) ht)))
           88       (error "~S is not a valid encoding designator" encoding)))