1
0
mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-12 09:28:24 +00:00
emacs/lisp/progmodes/ebnf-iso.el
2003-02-10 09:56:14 +00:00

616 lines
17 KiB
EmacsLisp
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; ebnf-iso.el --- parser for ISO EBNF
;; Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
;; Author: Vinicius Jose Latorre <vinicius@cpqd.com.br>
;; Maintainer: Vinicius Jose Latorre <vinicius@cpqd.com.br>
;; Keywords: wp, ebnf, PostScript
;; Time-stamp: <2003-02-10 10:26:32 jbarranquero>
;; Version: 1.6
;; 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 2, 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; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;
;; This is part of ebnf2ps package.
;;
;; This package defines a parser for ISO EBNF.
;;
;; See ebnf2ps.el for documentation.
;;
;;
;; ISO EBNF Syntax
;; ---------------
;;
;; See the URL:
;; `http://www.cl.cam.ac.uk/~mgk25/iso-ebnf.html'
;; ("International Standard of the ISO EBNF Notation").
;;
;;
;; ISO EBNF = syntax rule, {syntax rule};
;;
;; syntax rule = meta identifier, '=', definition list, ';';
;;
;; definition list = single definition, {'|', single definition};
;;
;; single definition = term, {',', term};
;;
;; term = factor, ['-', exception];
;;
;; exception = factor (* without <meta identifier> *);
;;
;; factor = [integer, '*'], primary;
;;
;; primary = optional sequence | repeated sequence | special sequence
;; | grouped sequence | meta identifier | terminal string
;; | empty;
;;
;; empty = ;
;;
;; optional sequence = '[', definition list, ']';
;;
;; repeated sequence = '{', definition list, '}';
;;
;; grouped sequence = '(', definition list, ')';
;;
;; terminal string = "'", character - "'", {character - "'"}, "'"
;; | '"', character - '"', {character - '"'}, '"';
;;
;; special sequence = '?', {character - '?'}, '?';
;;
;; meta identifier = letter, { letter | decimal digit | ' ' };
;;
;; integer = decimal digit, {decimal digit};
;;
;; comment = '(*', {comment symbol}, '*)';
;;
;; comment symbol = comment (* <== NESTED COMMENT *)
;; | terminal string | special sequence | character;
;;
;; letter = ? A-Z a-z ?;
;;
;; decimal digit = ? 0-9 ?;
;;
;; character = letter | decimal digit
;; | ',' | '=' | '|' | '/' | '!' | '*' | '(' | ')' | '[' | ']' | '{'
;; | '}' | "'" | '"' | '?' | '-' | ';' | '.' | ' ' | ':' | '+' | '_'
;; | '%' | '@' | '&' | '#' | '$' | '<' | '>' | '\' | '^' | '`' | '~';
;;
;;
;; There is also the following alternative representation:
;;
;; STANDARD ALTERNATIVE
;; | ==> / or !
;; [ ==> (/
;; ] ==> /)
;; { ==> (:
;; } ==> :)
;; ; ==> .
;;
;;
;; Differences Between ISO EBNF And ebnf2ps ISO EBNF
;; -------------------------------------------------
;;
;; ISO EBNF accepts the characters given by <character> production above,
;; HORIZONTAL TAB (^I), VERTICAL TAB (^K), NEWLINE (^J or ^M) and FORM FEED
;; (^L), any other characters are illegal. But ebnf2ps accepts also the
;; european 8-bit accentuated characters (from \240 to \377).
;;
;;
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Code:
(require 'ebnf-otz)
(defvar ebnf-iso-lex nil
"Value returned by `ebnf-iso-lex' function.")
(defconst ebnf-no-meta-identifier nil)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Syntactic analyzer
;;; ISO EBNF = syntax rule, {syntax rule};
(defun ebnf-iso-parser (start)
"ISO EBNF parser."
(let ((total (+ (- ebnf-limit start) 1))
(bias (1- start))
(origin (point))
syntax-list token rule)
(goto-char start)
(setq token (ebnf-iso-lex))
(and (eq token 'end-of-input)
(error "Invalid ISO EBNF file format"))
(while (not (eq token 'end-of-input))
(ebnf-message-float
"Parsing...%s%%"
(/ (* (- (point) bias) 100.0) total))
(setq token (ebnf-iso-syntax-rule token)
rule (cdr token)
token (car token))
(or (ebnf-add-empty-rule-list rule)
(setq syntax-list (cons rule syntax-list))))
(goto-char origin)
syntax-list))
;;; syntax rule = meta identifier, '=', definition list, ';';
(defun ebnf-iso-syntax-rule (token)
(let ((header ebnf-iso-lex)
(action ebnf-action)
body)
(setq ebnf-action nil)
(or (eq token 'non-terminal)
(error "Invalid meta identifier syntax rule"))
(or (eq (ebnf-iso-lex) 'equal)
(error "Invalid syntax rule: missing `='"))
(setq body (ebnf-iso-definition-list))
(or (eq (car body) 'period)
(error "Invalid syntax rule: missing `;' or `.'"))
(setq body (cdr body))
(ebnf-eps-add-production header)
(cons (ebnf-iso-lex)
(ebnf-make-production header body action))))
;;; definition list = single definition, {'|', single definition};
(defun ebnf-iso-definition-list ()
(let (body sequence)
(while (eq (car (setq sequence (ebnf-iso-single-definition)))
'alternative)
(setq sequence (cdr sequence)
body (cons sequence body)))
(ebnf-token-alternative body sequence)))
;;; single definition = term, {',', term};
(defun ebnf-iso-single-definition ()
(let (token seq term)
(while (and (setq term (ebnf-iso-term (ebnf-iso-lex))
token (car term)
term (cdr term))
(eq token 'catenate))
(setq seq (cons term seq)))
(cons token
(cond
;; null sequence
((null seq)
term)
;; sequence with only one element
((and (null term) (= (length seq) 1))
(car seq))
;; a real sequence
(t
(ebnf-make-sequence (nreverse (cons term seq))))
))))
;;; term = factor, ['-', exception];
;;;
;;; exception = factor (* without <meta identifier> *);
(defun ebnf-iso-term (token)
(let ((factor (ebnf-iso-factor token)))
(if (not (eq (car factor) 'except))
;; factor
factor
;; factor - exception
(let ((ebnf-no-meta-identifier t))
(ebnf-token-except (cdr factor) (ebnf-iso-factor (ebnf-iso-lex)))))))
;;; factor = [integer, '*'], primary;
(defun ebnf-iso-factor (token)
(if (eq token 'integer)
(let ((times ebnf-iso-lex))
(or (eq (ebnf-iso-lex) 'repeat)
(error "Missing `*'"))
(ebnf-token-repeat times (ebnf-iso-primary (ebnf-iso-lex))))
(ebnf-iso-primary token)))
;;; primary = optional sequence | repeated sequence | special sequence
;;; | grouped sequence | meta identifier | terminal string
;;; | empty;
;;;
;;; empty = ;
;;;
;;; optional sequence = '[', definition list, ']';
;;;
;;; repeated sequence = '{', definition list, '}';
;;;
;;; grouped sequence = '(', definition list, ')';
;;;
;;; terminal string = "'", character - "'", {character - "'"}, "'"
;;; | '"', character - '"', {character - '"'}, '"';
;;;
;;; special sequence = '?', {character - '?'}, '?';
;;;
;;; meta identifier = letter, {letter | decimal digit};
(defun ebnf-iso-primary (token)
(let ((primary
(cond
;; terminal string
((eq token 'terminal)
(ebnf-make-terminal ebnf-iso-lex))
;; meta identifier
((eq token 'non-terminal)
(ebnf-make-non-terminal ebnf-iso-lex))
;; special sequence
((eq token 'special)
(ebnf-make-special ebnf-iso-lex))
;; grouped sequence
((eq token 'begin-group)
(let ((body (ebnf-iso-definition-list)))
(or (eq (car body) 'end-group)
(error "Missing `)'"))
(cdr body)))
;; optional sequence
((eq token 'begin-optional)
(let ((body (ebnf-iso-definition-list)))
(or (eq (car body) 'end-optional)
(error "Missing `]' or `/)'"))
(ebnf-token-optional (cdr body))))
;; repeated sequence
((eq token 'begin-zero-or-more)
(let* ((body (ebnf-iso-definition-list))
(repeat (cdr body)))
(or (eq (car body) 'end-zero-or-more)
(error "Missing `}' or `:)'"))
(ebnf-make-zero-or-more repeat)))
;; empty
(t
nil)
)))
(cons (if primary
(ebnf-iso-lex)
token)
primary)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Lexical analyzer
(defconst ebnf-iso-token-table
;; control character & 8-bit character are set to `error'
(let ((table (make-vector 256 'error))
(char ?\040))
;; printable character
(while (< char ?\060)
(aset table char 'character)
(setq char (1+ char)))
;; digits:
(while (< char ?\072)
(aset table char 'integer)
(setq char (1+ char)))
(while (< char ?\101)
(aset table char 'character)
(setq char (1+ char)))
;; upper case letters:
(while (< char ?\133)
(aset table char 'non-terminal)
(setq char (1+ char)))
(while (< char ?\141)
(aset table char 'character)
(setq char (1+ char)))
;; lower case letters:
(while (< char ?\173)
(aset table char 'non-terminal)
(setq char (1+ char)))
(while (< char ?\177)
(aset table char 'character)
(setq char (1+ char)))
;; European 8-bit accentuated characters:
(setq char ?\240)
(while (< char ?\400)
(aset table char 'non-terminal)
(setq char (1+ char)))
;; Override space characters:
(aset table ?\013 'space) ; [VT] vertical tab
(aset table ?\n 'space) ; [NL] linefeed
(aset table ?\r 'space) ; [CR] carriage return
(aset table ?\t 'space) ; [HT] horizontal tab
(aset table ?\ 'space) ; [SP] space
;; Override form feed character:
(aset table ?\f 'form-feed) ; [FF] form feed
;; Override other lexical characters:
(aset table ?\" 'double-terminal)
(aset table ?\' 'single-terminal)
(aset table ?\? 'special)
(aset table ?* 'repeat)
(aset table ?, 'catenate)
(aset table ?- 'except)
(aset table ?= 'equal)
(aset table ?\) 'end-group)
table)
"Vector used to map characters to a lexical token.")
(defun ebnf-iso-initialize ()
"Initialize ISO EBNF token table."
(if ebnf-iso-alternative-p
;; Override alternative lexical characters:
(progn
(aset ebnf-iso-token-table ?\( 'left-parenthesis)
(aset ebnf-iso-token-table ?\[ 'character)
(aset ebnf-iso-token-table ?\] 'character)
(aset ebnf-iso-token-table ?\{ 'character)
(aset ebnf-iso-token-table ?\} 'character)
(aset ebnf-iso-token-table ?| 'character)
(aset ebnf-iso-token-table ?\; 'character)
(aset ebnf-iso-token-table ?/ 'slash)
(aset ebnf-iso-token-table ?! 'alternative)
(aset ebnf-iso-token-table ?: 'colon)
(aset ebnf-iso-token-table ?. 'period))
;; Override standard lexical characters:
(aset ebnf-iso-token-table ?\( 'begin-parenthesis)
(aset ebnf-iso-token-table ?\[ 'begin-optional)
(aset ebnf-iso-token-table ?\] 'end-optional)
(aset ebnf-iso-token-table ?\{ 'begin-zero-or-more)
(aset ebnf-iso-token-table ?\} 'end-zero-or-more)
(aset ebnf-iso-token-table ?| 'alternative)
(aset ebnf-iso-token-table ?\; 'period)
(aset ebnf-iso-token-table ?/ 'character)
(aset ebnf-iso-token-table ?! 'character)
(aset ebnf-iso-token-table ?: 'character)
(aset ebnf-iso-token-table ?. 'character)))
;; replace the range "\240-\377" (see `ebnf-range-regexp').
(defconst ebnf-iso-non-terminal-chars
(ebnf-range-regexp " 0-9A-Za-z" ?\240 ?\377))
(defun ebnf-iso-lex ()
"Lexical analyser for ISO EBNF.
Return a lexical token.
See documentation for variable `ebnf-iso-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-iso-token-table (following-char)))
(cond
((eq token 'space)
(skip-chars-forward " \013\n\r\t" ebnf-limit)
(< (point) ebnf-limit))
((or (eq token 'begin-parenthesis)
(eq token 'left-parenthesis))
(forward-char)
(if (/= (following-char) ?*)
;; no comment
nil
;; comment
(ebnf-iso-skip-comment)
t))
((eq token 'form-feed)
(forward-char)
(setq ebnf-action 'form-feed))
(t nil)
)))
(cond
;; end of input
((>= (point) ebnf-limit)
'end-of-input)
;; error
((eq token 'error)
(error "Illegal character"))
;; integer
((eq token 'integer)
(setq ebnf-iso-lex (ebnf-buffer-substring "0-9"))
'integer)
;; special: ?special?
((eq token 'special)
(setq ebnf-iso-lex (concat "?"
(ebnf-string " ->@-~" ?\? "special")
"?"))
'special)
;; terminal: "string"
((eq token 'double-terminal)
(setq ebnf-iso-lex (ebnf-string " !#-~" ?\" "terminal"))
'terminal)
;; terminal: 'string'
((eq token 'single-terminal)
(setq ebnf-iso-lex (ebnf-string " -&(-~" ?\' "terminal"))
'terminal)
;; non-terminal
((eq token 'non-terminal)
(setq ebnf-iso-lex
(ebnf-iso-normalize
(ebnf-trim-right
(ebnf-buffer-substring ebnf-iso-non-terminal-chars))))
(and ebnf-no-meta-identifier
(error "Exception sequence should not contain a meta identifier"))
'non-terminal)
;; begin optional, begin list or begin group
((eq token 'left-parenthesis)
(forward-char)
(cond ((= (following-char) ?/)
(forward-char)
'begin-optional)
((= (following-char) ?:)
(forward-char)
'begin-zero-or-more)
(t
'begin-group)
))
;; end optional or alternative
((eq token 'slash)
(forward-char)
(if (/= (following-char) ?\))
'alternative
(forward-char)
'end-optional))
;; end list
((eq token 'colon)
(forward-char)
(if (/= (following-char) ?\))
'character
(forward-char)
'end-zero-or-more))
;; begin group
((eq token 'begin-parenthesis)
'begin-group)
;; miscellaneous
(t
(forward-char)
token)
))))
;; replace the range "\177-\237" (see `ebnf-range-regexp').
(defconst ebnf-iso-comment-chars
(ebnf-range-regexp "^*(\000-\010\016-\037" ?\177 ?\237))
(defun ebnf-iso-skip-comment ()
(forward-char)
(cond
;; open EPS file
((and ebnf-eps-executing (= (following-char) ?\[))
(ebnf-eps-add-context (ebnf-iso-eps-filename)))
;; close EPS file
((and ebnf-eps-executing (= (following-char) ?\]))
(ebnf-eps-remove-context (ebnf-iso-eps-filename)))
;; any other action in comment
(t
(setq ebnf-action (aref ebnf-comment-table (following-char))))
)
(let ((pair 1))
(while (> pair 0)
(skip-chars-forward ebnf-iso-comment-chars ebnf-limit)
(cond ((>= (point) ebnf-limit)
(error "Missing end of comment: `*)'"))
((= (following-char) ?*)
(skip-chars-forward "*" ebnf-limit)
(when (= (following-char) ?\))
;; end of comment
(forward-char)
(setq pair (1- pair))))
((= (following-char) ?\()
(skip-chars-forward "(" ebnf-limit)
(when (= (following-char) ?*)
;; beginning of comment
(forward-char)
(setq pair (1+ pair))))
(t
(error "Illegal character"))
))))
(defun ebnf-iso-eps-filename ()
(forward-char)
(buffer-substring-no-properties
(point)
(let ((chars (concat ebnf-iso-comment-chars "\n"))
found)
(while (not found)
(skip-chars-forward chars ebnf-limit)
(setq found
(cond ((>= (point) ebnf-limit)
(point))
((= (following-char) ?*)
(skip-chars-forward "*" ebnf-limit)
(if (/= (following-char) ?\))
nil
(backward-char)
(point)))
((= (following-char) ?\()
(forward-char)
(if (/= (following-char) ?*)
nil
(backward-char)
(point)))
(t
(point))
)))
found)))
(defun ebnf-iso-normalize (str)
(if (not ebnf-iso-normalize-p)
str
(let ((len (length str))
(stri 0)
(spaces 0))
;; count exceeding spaces
(while (< stri len)
(if (/= (aref str stri) ?\ )
(setq stri (1+ stri))
(setq stri (1+ stri))
(while (and (< stri len) (= (aref str stri) ?\ ))
(setq stri (1+ stri)
spaces (1+ spaces)))))
(if (zerop spaces)
;; no exceeding space
str
;; at least one exceeding space
(let ((new (make-string (- len spaces) ?\ ))
(newi 0))
;; eliminate exceeding spaces
(setq stri 0)
(while (> spaces 0)
(if (/= (aref str stri) ?\ )
(progn
(aset new newi (aref str stri))
(setq stri (1+ stri)
newi (1+ newi)))
(aset new newi (aref str stri))
(setq stri (1+ stri)
newi (1+ newi))
(while (and (> spaces 0) (= (aref str stri) ?\ ))
(setq stri (1+ stri)
spaces (1- spaces)))))
;; remaining is normalized
(while (< stri len)
(aset new newi (aref str stri))
(setq stri (1+ stri)
newi (1+ newi)))
new)))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(provide 'ebnf-iso)
;;; ebnf-iso.el ends here