mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-13 09:32:47 +00:00
609 lines
18 KiB
EmacsLisp
609 lines
18 KiB
EmacsLisp
;;; ebnf-bnf.el --- parser for EBNF
|
||
|
||
;; Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
|
||
;; Free Software Foundation, Inc.
|
||
|
||
;; Author: Vinicius Jose Latorre <viniciusjl@ig.com.br>
|
||
;; Maintainer: Vinicius Jose Latorre <viniciusjl@ig.com.br>
|
||
;; Keywords: wp, ebnf, PostScript
|
||
;; Version: 1.10
|
||
|
||
;; This file is part of GNU Emacs.
|
||
|
||
;; GNU Emacs 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.
|
||
|
||
;; GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
|
||
|
||
;;; Commentary:
|
||
|
||
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
;;
|
||
;;
|
||
;; This is part of ebnf2ps package.
|
||
;;
|
||
;; This package defines a parser for EBNF.
|
||
;;
|
||
;; See ebnf2ps.el for documentation.
|
||
;;
|
||
;;
|
||
;; EBNF Syntax
|
||
;; -----------
|
||
;;
|
||
;; The current EBNF that ebnf2ps accepts has the following constructions:
|
||
;;
|
||
;; ; comment (until end of line)
|
||
;; A non-terminal
|
||
;; "C" terminal
|
||
;; ?C? special
|
||
;; $A default non-terminal
|
||
;; $"C" default terminal
|
||
;; $?C? default special
|
||
;; A = B. production (A is the header and B the body)
|
||
;; C D sequence (C occurs before D)
|
||
;; C | D alternative (C or D occurs)
|
||
;; A - B exception (A excluding B, B without any non-terminal)
|
||
;; n * A repetition (A repeats at least n (integer) times)
|
||
;; n * n A repetition (A repeats exactly n (integer) times)
|
||
;; n * m A repetition (A repeats at least n (integer) and at most
|
||
;; m (integer) times)
|
||
;; (C) group (expression C is grouped together)
|
||
;; [C] optional (C may or not occurs)
|
||
;; C+ one or more occurrences of C
|
||
;; {C}+ one or more occurrences of C
|
||
;; {C}* zero or more occurrences of C
|
||
;; {C} zero or more occurrences of C
|
||
;; C / D equivalent to: C {D C}*
|
||
;; {C || D}+ equivalent to: C {D C}*
|
||
;; {C || D}* equivalent to: [C {D C}*]
|
||
;; {C || D} equivalent to: [C {D C}*]
|
||
;;
|
||
;; The EBNF syntax written using the notation above is:
|
||
;;
|
||
;; EBNF = {production}+.
|
||
;;
|
||
;; production = non_terminal "=" body ".". ;; production
|
||
;;
|
||
;; body = {sequence || "|"}*. ;; alternative
|
||
;;
|
||
;; sequence = {exception}*. ;; sequence
|
||
;;
|
||
;; exception = repeat [ "-" repeat]. ;; exception
|
||
;;
|
||
;; repeat = [ integer "*" [ integer ]] term. ;; repetition
|
||
;;
|
||
;; term = factor
|
||
;; | [factor] "+" ;; one-or-more
|
||
;; | [factor] "/" [factor] ;; one-or-more
|
||
;; .
|
||
;;
|
||
;; factor = [ "$" ] "\"" terminal "\"" ;; terminal
|
||
;; | [ "$" ] non_terminal ;; non-terminal
|
||
;; | [ "$" ] "?" special "?" ;; special
|
||
;; | "(" body ")" ;; group
|
||
;; | "[" body "]" ;; zero-or-one
|
||
;; | "{" body [ "||" body ] "}+" ;; one-or-more
|
||
;; | "{" body [ "||" body ] "}*" ;; zero-or-more
|
||
;; | "{" body [ "||" body ] "}" ;; zero-or-more
|
||
;; .
|
||
;;
|
||
;; non_terminal = "[!#%&'*-,0-:<>@-Z\\\\^-z~\\240-\\377]+".
|
||
;; ;; that is, a valid non_terminal accepts decimal digits, letters (upper
|
||
;; ;; and lower), 8-bit accentuated characters,
|
||
;; ;; "!", "#", "%", "&", "'", "*", "+", ",", ":",
|
||
;; ;; "<", ">", "@", "\", "^", "_", "`" and "~".
|
||
;;
|
||
;; terminal = "\\([^\"\\]\\|\\\\[ -~\\240-\\377]\\)+".
|
||
;; ;; that is, a valid terminal accepts any printable character (including
|
||
;; ;; 8-bit accentuated characters) except `"', as `"' is used to delimit a
|
||
;; ;; terminal. Also, accepts escaped characters, that is, a character
|
||
;; ;; pair starting with `\' followed by a printable character, for
|
||
;; ;; example: \", \\.
|
||
;;
|
||
;; special = "[^?\\000-\\010\\012-\\037\\177-\\237]*".
|
||
;; ;; that is, a valid special accepts any printable character (including
|
||
;; ;; 8-bit accentuated characters) and tabs except `?', as `?' is used to
|
||
;; ;; delimit a special.
|
||
;;
|
||
;; integer = "[0-9]+".
|
||
;; ;; that is, an integer is a sequence of one or more decimal digits.
|
||
;;
|
||
;; comment = ";" "[^\\n\\000-\\010\\016-\\037\\177-\\237]*" "\\n".
|
||
;; ;; that is, a comment starts with the character `;' and terminates at end
|
||
;; ;; of line. Also, it only accepts printable characters (including 8-bit
|
||
;; ;; accentuated characters) and tabs.
|
||
;;
|
||
;;
|
||
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
||
;;; Code:
|
||
|
||
|
||
(require 'ebnf-otz)
|
||
|
||
|
||
(defvar ebnf-bnf-lex nil
|
||
"Value returned by `ebnf-bnf-lex' function.")
|
||
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
;; Syntactic analyzer
|
||
|
||
|
||
;;; EBNF = {production}+.
|
||
|
||
(defun ebnf-bnf-parser (start)
|
||
"EBNF parser."
|
||
(let ((total (+ (- ebnf-limit start) 1))
|
||
(bias (1- start))
|
||
(origin (point))
|
||
prod-list token rule)
|
||
(goto-char start)
|
||
(setq token (ebnf-bnf-lex))
|
||
(and (eq token 'end-of-input)
|
||
(error "Invalid EBNF file format"))
|
||
(while (not (eq token 'end-of-input))
|
||
(ebnf-message-float
|
||
"Parsing...%s%%"
|
||
(/ (* (- (point) bias) 100.0) total))
|
||
(setq token (ebnf-production token)
|
||
rule (cdr token)
|
||
token (car token))
|
||
(or (ebnf-add-empty-rule-list rule)
|
||
(setq prod-list (cons rule prod-list))))
|
||
(goto-char origin)
|
||
prod-list))
|
||
|
||
|
||
;;; production = non-terminal "=" body ".".
|
||
|
||
(defun ebnf-production (token)
|
||
(let ((header ebnf-bnf-lex)
|
||
(action ebnf-action)
|
||
body)
|
||
(setq ebnf-action nil)
|
||
(or (eq token 'non-terminal)
|
||
(error "Invalid header production"))
|
||
(or (eq (ebnf-bnf-lex) 'equal)
|
||
(error "Invalid production: missing `='"))
|
||
(setq body (ebnf-body))
|
||
(or (eq (car body) 'period)
|
||
(error "Invalid production: missing `.'"))
|
||
(setq body (cdr body))
|
||
(ebnf-eps-add-production header)
|
||
(cons (ebnf-bnf-lex)
|
||
(ebnf-make-production header body action))))
|
||
|
||
|
||
;;; body = {sequence || "|"}*.
|
||
|
||
(defun ebnf-body ()
|
||
(let (body sequence)
|
||
(while (eq (car (setq sequence (ebnf-sequence))) 'alternative)
|
||
(setq sequence (cdr sequence)
|
||
body (cons sequence body)))
|
||
(ebnf-token-alternative body sequence)))
|
||
|
||
|
||
;;; sequence = {exception}*.
|
||
|
||
(defun ebnf-sequence ()
|
||
(let ((token (ebnf-bnf-lex))
|
||
seq term)
|
||
(while (setq term (ebnf-exception token)
|
||
token (car term)
|
||
term (cdr term))
|
||
(setq seq (cons term seq)))
|
||
(cons token
|
||
(ebnf-token-sequence seq))))
|
||
|
||
|
||
;;; exception = repeat [ "-" repeat].
|
||
|
||
(defun ebnf-exception (token)
|
||
(let ((term (ebnf-repeat token)))
|
||
(if (not (eq (car term) 'except))
|
||
;; repeat
|
||
term
|
||
;; repeat - repeat
|
||
(let ((exception (ebnf-repeat (ebnf-bnf-lex))))
|
||
(ebnf-no-non-terminal (cdr exception))
|
||
(ebnf-token-except (cdr term) exception)))))
|
||
|
||
|
||
(defun ebnf-no-non-terminal (node)
|
||
(and (vectorp node)
|
||
(let ((kind (ebnf-node-kind node)))
|
||
(cond
|
||
((eq kind 'ebnf-generate-non-terminal)
|
||
(error "Exception sequence should not contain a non-terminal"))
|
||
((eq kind 'ebnf-generate-repeat)
|
||
(ebnf-no-non-terminal (ebnf-node-separator node)))
|
||
((memq kind '(ebnf-generate-optional ebnf-generate-except))
|
||
(ebnf-no-non-terminal (ebnf-node-list node)))
|
||
((memq kind '(ebnf-generate-one-or-more ebnf-generate-zero-or-more))
|
||
(ebnf-no-non-terminal (ebnf-node-list node))
|
||
(ebnf-no-non-terminal (ebnf-node-separator node)))
|
||
((memq kind '(ebnf-generate-alternative ebnf-generate-sequence))
|
||
(let ((seq (ebnf-node-list node)))
|
||
(while seq
|
||
(ebnf-no-non-terminal (car seq))
|
||
(setq seq (cdr seq)))))
|
||
))))
|
||
|
||
|
||
;;; repeat = [ integer "*" [ integer ]] term.
|
||
|
||
(defun ebnf-repeat (token)
|
||
(if (not (eq token 'integer))
|
||
(ebnf-term token)
|
||
(let ((times ebnf-bnf-lex)
|
||
upper)
|
||
(or (eq (ebnf-bnf-lex) 'repeat)
|
||
(error "Missing `*'"))
|
||
(setq token (ebnf-bnf-lex))
|
||
(when (eq token 'integer)
|
||
(setq upper ebnf-bnf-lex
|
||
token (ebnf-bnf-lex)))
|
||
(ebnf-token-repeat times (ebnf-term token) upper))))
|
||
|
||
|
||
;;; term = factor
|
||
;;; | [factor] "+" ;; one-or-more
|
||
;;; | [factor] "/" [factor] ;; one-or-more
|
||
;;; .
|
||
|
||
(defun ebnf-term (token)
|
||
(let ((factor (ebnf-factor token)))
|
||
(and factor
|
||
(setq token (ebnf-bnf-lex)))
|
||
(cond
|
||
;; [factor] +
|
||
((eq token 'one-or-more)
|
||
(cons (ebnf-bnf-lex)
|
||
(and factor
|
||
(let ((kind (ebnf-node-kind factor)))
|
||
(cond
|
||
;; { A }+ + ==> { A }+
|
||
;; { A }* + ==> { A }*
|
||
((memq kind '(ebnf-generate-zero-or-more
|
||
ebnf-generate-one-or-more))
|
||
factor)
|
||
;; [ A ] + ==> { A }*
|
||
((eq kind 'ebnf-generate-optional)
|
||
(ebnf-make-zero-or-more (list factor)))
|
||
;; A +
|
||
(t
|
||
(ebnf-make-one-or-more (list factor)))
|
||
)))))
|
||
;; [factor] / [factor]
|
||
((eq token 'list)
|
||
(setq token (ebnf-bnf-lex))
|
||
(let ((sep (ebnf-factor token)))
|
||
(and sep
|
||
(setq factor (or factor (ebnf-make-empty))))
|
||
(cons (if sep
|
||
(ebnf-bnf-lex)
|
||
token)
|
||
(and factor
|
||
(ebnf-make-one-or-more factor sep)))))
|
||
;; factor
|
||
(t
|
||
(cons token factor))
|
||
)))
|
||
|
||
|
||
;;; factor = [ "$" ] "\"" terminal "\"" ;; terminal
|
||
;;; | [ "$" ] non_terminal ;; non-terminal
|
||
;;; | [ "$" ] "?" special "?" ;; special
|
||
;;; | "(" body ")" ;; group
|
||
;;; | "[" body "]" ;; zero-or-one
|
||
;;; | "{" body [ "||" body ] "}+" ;; one-or-more
|
||
;;; | "{" body [ "||" body ] "}*" ;; zero-or-more
|
||
;;; | "{" body [ "||" body ] "}" ;; zero-or-more
|
||
;;; .
|
||
|
||
(defun ebnf-factor (token)
|
||
(cond
|
||
;; terminal
|
||
((eq token 'terminal)
|
||
(ebnf-make-terminal ebnf-bnf-lex))
|
||
;; non-terminal
|
||
((eq token 'non-terminal)
|
||
(ebnf-make-non-terminal ebnf-bnf-lex))
|
||
;; special
|
||
((eq token 'special)
|
||
(ebnf-make-special ebnf-bnf-lex))
|
||
;; group
|
||
((eq token 'begin-group)
|
||
(let ((body (ebnf-body)))
|
||
(or (eq (car body) 'end-group)
|
||
(error "Missing `)'"))
|
||
(cdr body)))
|
||
;; optional
|
||
((eq token 'begin-optional)
|
||
(let ((body (ebnf-body)))
|
||
(or (eq (car body) 'end-optional)
|
||
(error "Missing `]'"))
|
||
(ebnf-token-optional (cdr body))))
|
||
;; list
|
||
((eq token 'begin-list)
|
||
(let* ((body (ebnf-body))
|
||
(token (car body))
|
||
(list-part (cdr body))
|
||
sep-part)
|
||
(and (eq token 'list-separator)
|
||
;; { A || B }
|
||
(setq body (ebnf-body) ; get separator
|
||
token (car body)
|
||
sep-part (cdr body)))
|
||
(cond
|
||
;; { A }+
|
||
((eq token 'end-one-or-more)
|
||
(ebnf-make-one-or-more list-part sep-part))
|
||
;; { A }*
|
||
((eq token 'end-zero-or-more)
|
||
(ebnf-make-zero-or-more list-part sep-part))
|
||
(t
|
||
(error "Missing `}+', `}*' or `}'"))
|
||
)))
|
||
;; no term
|
||
(t
|
||
nil)
|
||
))
|
||
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
;; Lexical analyzer
|
||
|
||
|
||
(defconst ebnf-bnf-token-table (make-vector 256 'error)
|
||
"Vector used to map characters to a lexical token.")
|
||
|
||
|
||
(defun ebnf-bnf-initialize ()
|
||
"Initialize EBNF token table."
|
||
;; control character & control 8-bit character are set to `error'
|
||
(let ((char ?\040))
|
||
;; printable character:
|
||
(while (< char ?\060)
|
||
(aset ebnf-bnf-token-table char 'non-terminal)
|
||
(setq char (1+ char)))
|
||
;; digits:
|
||
(while (< char ?\072)
|
||
(aset ebnf-bnf-token-table char 'integer)
|
||
(setq char (1+ char)))
|
||
;; printable character:
|
||
(while (< char ?\177)
|
||
(aset ebnf-bnf-token-table char 'non-terminal)
|
||
(setq char (1+ char)))
|
||
;; European 8-bit accentuated characters:
|
||
(setq char ?\240)
|
||
(while (< char ?\400)
|
||
(aset ebnf-bnf-token-table char 'non-terminal)
|
||
(setq char (1+ char)))
|
||
;; Override space characters:
|
||
(aset ebnf-bnf-token-table ?\013 'space) ; [VT] vertical tab
|
||
(aset ebnf-bnf-token-table ?\n 'space) ; [NL] linefeed
|
||
(aset ebnf-bnf-token-table ?\r 'space) ; [CR] carriage return
|
||
(aset ebnf-bnf-token-table ?\t 'space) ; [HT] horizontal tab
|
||
(aset ebnf-bnf-token-table ?\ 'space) ; [SP] space
|
||
;; Override form feed character:
|
||
(aset ebnf-bnf-token-table ?\f 'form-feed) ; [FF] form feed
|
||
;; Override other lexical characters:
|
||
(aset ebnf-bnf-token-table ?\" 'terminal)
|
||
(aset ebnf-bnf-token-table ?\? 'special)
|
||
(aset ebnf-bnf-token-table ?\( 'begin-group)
|
||
(aset ebnf-bnf-token-table ?\) 'end-group)
|
||
(aset ebnf-bnf-token-table ?* 'repeat)
|
||
(aset ebnf-bnf-token-table ?- 'except)
|
||
(aset ebnf-bnf-token-table ?= 'equal)
|
||
(aset ebnf-bnf-token-table ?\[ 'begin-optional)
|
||
(aset ebnf-bnf-token-table ?\] 'end-optional)
|
||
(aset ebnf-bnf-token-table ?\{ 'begin-list)
|
||
(aset ebnf-bnf-token-table ?| 'alternative)
|
||
(aset ebnf-bnf-token-table ?\} 'end-list)
|
||
(aset ebnf-bnf-token-table ?/ 'list)
|
||
(aset ebnf-bnf-token-table ?+ 'one-or-more)
|
||
(aset ebnf-bnf-token-table ?$ 'default)
|
||
;; Override comment character:
|
||
(aset ebnf-bnf-token-table ebnf-lex-comment-char 'comment)
|
||
;; Override end of production character:
|
||
(aset ebnf-bnf-token-table ebnf-lex-eop-char 'period)))
|
||
|
||
|
||
;; replace the range "\240-\377" (see `ebnf-range-regexp').
|
||
(defconst ebnf-bnf-non-terminal-chars
|
||
(ebnf-range-regexp "!#%&'*-,0-:<>@-Z\\\\^-z~" ?\240 ?\377))
|
||
|
||
|
||
(defun ebnf-bnf-lex ()
|
||
"Lexical analyzer for EBNF.
|
||
|
||
Return a lexical token.
|
||
|
||
See documentation for variable `ebnf-bnf-lex'."
|
||
(if (>= (point) ebnf-limit)
|
||
'end-of-input
|
||
(let (token)
|
||
;; skip spaces and comments
|
||
(while (if (> (following-char) 255)
|
||
(progn
|
||
(setq token 'error)
|
||
nil)
|
||
(setq token (aref ebnf-bnf-token-table (following-char)))
|
||
(cond
|
||
((eq token 'space)
|
||
(skip-chars-forward " \013\n\r\t" ebnf-limit)
|
||
(< (point) ebnf-limit))
|
||
((eq token 'comment)
|
||
(ebnf-bnf-skip-comment))
|
||
((eq token 'form-feed)
|
||
(forward-char)
|
||
(setq ebnf-action 'form-feed))
|
||
(t nil)
|
||
)))
|
||
(setq ebnf-default-p nil)
|
||
(cond
|
||
;; end of input
|
||
((>= (point) ebnf-limit)
|
||
'end-of-input)
|
||
;; error
|
||
((eq token 'error)
|
||
(error "Invalid character"))
|
||
;; default
|
||
((eq token 'default)
|
||
(forward-char)
|
||
(if (memq (aref ebnf-bnf-token-table (following-char))
|
||
'(terminal non-terminal special))
|
||
(prog1
|
||
(ebnf-bnf-lex)
|
||
(setq ebnf-default-p t))
|
||
(error "Invalid `default' element")))
|
||
;; integer
|
||
((eq token 'integer)
|
||
(setq ebnf-bnf-lex (ebnf-buffer-substring "0-9"))
|
||
'integer)
|
||
;; special: ?special?
|
||
((eq token 'special)
|
||
(setq ebnf-bnf-lex (concat (and ebnf-special-show-delimiter "?")
|
||
(ebnf-string " ->@-~" ?\? "special")
|
||
(and ebnf-special-show-delimiter "?")))
|
||
'special)
|
||
;; terminal: "string"
|
||
((eq token 'terminal)
|
||
(setq ebnf-bnf-lex (ebnf-unescape-string (ebnf-get-string)))
|
||
'terminal)
|
||
;; non-terminal or terminal
|
||
((eq token 'non-terminal)
|
||
(setq ebnf-bnf-lex (ebnf-buffer-substring ebnf-bnf-non-terminal-chars))
|
||
(let ((case-fold-search ebnf-case-fold-search)
|
||
match)
|
||
(if (and ebnf-terminal-regexp
|
||
(setq match (string-match ebnf-terminal-regexp
|
||
ebnf-bnf-lex))
|
||
(zerop match)
|
||
(= (match-end 0) (length ebnf-bnf-lex)))
|
||
'terminal
|
||
'non-terminal)))
|
||
;; end of list: }+, }*, }
|
||
((eq token 'end-list)
|
||
(forward-char)
|
||
(cond
|
||
((= (following-char) ?+)
|
||
(forward-char)
|
||
'end-one-or-more)
|
||
((= (following-char) ?*)
|
||
(forward-char)
|
||
'end-zero-or-more)
|
||
(t
|
||
'end-zero-or-more)
|
||
))
|
||
;; alternative: |, ||
|
||
((eq token 'alternative)
|
||
(forward-char)
|
||
(if (/= (following-char) ?|)
|
||
'alternative
|
||
(forward-char)
|
||
'list-separator))
|
||
;; miscellaneous: {, (, ), [, ], ., =, /, +, -, *
|
||
(t
|
||
(forward-char)
|
||
token)
|
||
))))
|
||
|
||
|
||
;; replace the range "\177-\237" (see `ebnf-range-regexp').
|
||
(defconst ebnf-bnf-comment-chars
|
||
(ebnf-range-regexp "^\n\000-\010\016-\037" ?\177 ?\237))
|
||
|
||
|
||
(defun ebnf-bnf-skip-comment ()
|
||
(forward-char)
|
||
(cond
|
||
;; open EPS file
|
||
((and ebnf-eps-executing (= (following-char) ?\[))
|
||
(ebnf-eps-add-context (ebnf-bnf-eps-filename)))
|
||
;; close EPS file
|
||
((and ebnf-eps-executing (= (following-char) ?\]))
|
||
(ebnf-eps-remove-context (ebnf-bnf-eps-filename)))
|
||
;; EPS header
|
||
((and ebnf-eps-executing (= (following-char) ?H))
|
||
(ebnf-eps-header-comment (ebnf-bnf-eps-filename)))
|
||
;; EPS footer
|
||
((and ebnf-eps-executing (= (following-char) ?F))
|
||
(ebnf-eps-footer-comment (ebnf-bnf-eps-filename)))
|
||
;; any other action in comment
|
||
(t
|
||
(setq ebnf-action (aref ebnf-comment-table (following-char)))
|
||
(skip-chars-forward ebnf-bnf-comment-chars ebnf-limit))
|
||
)
|
||
;; check for a valid end of comment
|
||
(cond ((>= (point) ebnf-limit)
|
||
nil)
|
||
((= (following-char) ?\n)
|
||
(forward-char)
|
||
t)
|
||
(t
|
||
(error "Invalid character"))
|
||
))
|
||
|
||
|
||
(defun ebnf-bnf-eps-filename ()
|
||
(forward-char)
|
||
(ebnf-buffer-substring ebnf-bnf-comment-chars))
|
||
|
||
|
||
(defun ebnf-unescape-string (str)
|
||
(let* ((len (length str))
|
||
(size (1- len))
|
||
(istr 0)
|
||
(n-esc 0))
|
||
;; count number of escapes
|
||
(while (< istr size)
|
||
(setq istr (+ istr
|
||
(if (= (aref str istr) ?\\)
|
||
(progn
|
||
(setq n-esc (1+ n-esc))
|
||
2)
|
||
1))))
|
||
(if (zerop n-esc)
|
||
;; no escapes
|
||
str
|
||
;; at least one escape
|
||
(let ((new (make-string (- len n-esc) ?\ ))
|
||
(inew 0))
|
||
;; eliminate all escapes
|
||
(setq istr 0)
|
||
(while (> n-esc 0)
|
||
(and (= (aref str istr) ?\\)
|
||
(setq istr (1+ istr)
|
||
n-esc (1- n-esc)))
|
||
(aset new inew (aref str istr))
|
||
(setq inew (1+ inew)
|
||
istr (1+ istr)))
|
||
;; remaining string has no escape
|
||
(while (< istr len)
|
||
(aset new inew (aref str istr))
|
||
(setq inew (1+ inew)
|
||
istr (1+ istr)))
|
||
new))))
|
||
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
||
|
||
(provide 'ebnf-bnf)
|
||
|
||
|
||
;; arch-tag: 3b1834d3-8367-475b-80d5-8e0bbd00ce50
|
||
;;; ebnf-bnf.el ends here
|