external-format.lisp - clic - Clic is an command line interactive client for gopher written in Common LISP
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---
external-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)))