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emacs/lisp/progmodes/ebnf-yac.el
Mattias Engdegård d950a61fc8 Remove Emacs 20 bug workaround in ebnf2ps (bug#39663)
* lisp/progmodes/ebnf2ps.el (ebnf-range-regexp): Remove.  All calls
replaced with a string equivalent to the returned value.
2020-02-20 15:52:23 +01:00

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;;; ebnf-yac.el --- parser for Yacc/Bison
;; Copyright (C) 1999-2020 Free Software Foundation, Inc.
;; Author: Vinicius Jose Latorre <viniciusjl.gnu@gmail.com>
;; Keywords: wp, ebnf, PostScript
;; Old-Version: 1.4
;; Package: ebnf2ps
;; 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 <https://www.gnu.org/licenses/>.
;;; Commentary:
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;
;; This is part of ebnf2ps package.
;;
;; This package defines a parser for Yacc/Bison.
;;
;; See ebnf2ps.el for documentation.
;;
;;
;; Yacc/Bison Syntax
;; -----------------
;;
;; YACC = { YACC-Definitions }* "%%" { YACC-Rule }* [ "%%" [ YACC-Code ] ].
;;
;; YACC-Definitions = ( "%token" | "%left" | "%right" | "%nonassoc" )
;; [ "<" Name ">" ] Name-List
;; | "%prec" Name
;; | "any other Yacc definition"
;; .
;;
;; YACC-Code = "any C definition".
;;
;; YACC-Rule = Name ":" Alternative ";".
;;
;; Alternative = { Sequence || "|" }*.
;;
;; Sequence = { Factor }*.
;;
;; Factor = Name
;; | "'" "character" "'"
;; | "error"
;; | "{" "C like commands" "}"
;; .
;;
;; Name-List = { Name || "," }*.
;;
;; Name = "[A-Za-z][A-Za-z0-9_.]*".
;;
;; Comment = "/*" "any character, but the sequence \"*/\"" "*/"
;; | "//" "any character, but the newline \"\\n\"" "\\n".
;;
;;
;; In other words, a valid Name begins with a letter (upper or lower case)
;; followed by letters, decimal digits, underscore (_) or point (.). For
;; example: this_is_a_valid.name, Another_EXAMPLE, mIxEd.CaSe.
;;
;;
;; Acknowledgments
;; ---------------
;;
;; Thanks to Matthew K. Junker <junker@alum.mit.edu> for the suggestion to deal
;; with %right, %left and %prec pragmas. His suggestion was extended to deal
;; with %nonassoc pragma too.
;;
;;
;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Code:
(require 'ebnf-otz)
(defvar ebnf-yac-lex nil
"Value returned by `ebnf-yac-lex' function.")
(defvar ebnf-yac-token-list nil
"List of `%TOKEN' names.")
(defvar ebnf-yac-skip-char nil
"Non-nil means skip printable characters with no grammatical meaning.")
(defvar ebnf-yac-error nil
"Non-nil means \"error\" occurred.")
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Syntactic analyzer
;;; YACC = { YACC-Definitions }* "%%" { YACC-Rule }* [ "%%" [ YACC-Code ] ].
;;;
;;; YACC-Code = "any C definition".
(defun ebnf-yac-parser (start)
"yacc/Bison parser."
(let ((total (+ (- ebnf-limit start) 1))
(bias (1- start))
(origin (point))
syntax-list token rule)
(goto-char start)
(setq token (ebnf-yac-lex))
(and (eq token 'end-of-input)
(error "Invalid Yacc/Bison file format"))
(or (eq (ebnf-yac-definitions token) 'yac-separator)
(error "Missing `%%%%'"))
(setq token (ebnf-yac-lex))
(while (not (memq token '(end-of-input yac-separator)))
(ebnf-message-float
"Parsing...%s%%"
(/ (* (- (point) bias) 100.0) total))
(setq token (ebnf-yac-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))
;;; YACC-Definitions = ( "%token" | "%left" | "%right" | "%nonassoc" )
;;; [ "<" Name ">" ] Name-List
;;; | "%prec" Name
;;; | "any other Yacc definition"
;;; .
(defun ebnf-yac-definitions (token)
(let ((ebnf-yac-skip-char t))
(while (not (memq token '(yac-separator end-of-input)))
(setq token
(cond
;; ( "%token" | "%left" | "%right" | "%nonassoc" )
;; [ "<" Name ">" ] Name-List
((eq token 'yac-token)
(setq token (ebnf-yac-lex))
(when (eq token 'open-angle)
(or (eq (ebnf-yac-lex) 'non-terminal)
(error "Missing type name"))
(or (eq (ebnf-yac-lex) 'close-angle)
(error "Missing `>'"))
(setq token (ebnf-yac-lex)))
(setq token (ebnf-yac-name-list token)
ebnf-yac-token-list (nconc (cdr token)
ebnf-yac-token-list))
(car token))
;; "%prec" Name
((eq token 'yac-prec)
(or (eq (ebnf-yac-lex) 'non-terminal)
(error "Missing prec name"))
(ebnf-yac-lex))
;; "any other Yacc definition"
(t
(ebnf-yac-lex))
)))
token))
;;; YACC-Rule = Name ":" Alternative ";".
(defun ebnf-yac-rule (token)
(let ((header ebnf-yac-lex)
(action ebnf-action)
body)
(setq ebnf-action nil)
(or (eq token 'non-terminal)
(error "Invalid rule name"))
(or (eq (ebnf-yac-lex) 'colon)
(error "Invalid rule: missing `:'"))
(setq body (ebnf-yac-alternative))
(or (eq (car body) 'period)
(error "Invalid rule: missing `;'"))
(setq body (cdr body))
(ebnf-eps-add-production header)
(cons (ebnf-yac-lex)
(ebnf-make-production header body action))))
;;; Alternative = { Sequence || "|" }*.
(defun ebnf-yac-alternative ()
(let (body sequence)
(while (eq (car (setq sequence (ebnf-yac-sequence)))
'alternative)
(and (setq sequence (cdr sequence))
(setq body (cons sequence body))))
(ebnf-token-alternative body sequence)))
;;; Sequence = { Factor }*.
(defun ebnf-yac-sequence ()
(let (ebnf-yac-error token seq factor)
(while (setq token (ebnf-yac-lex)
factor (ebnf-yac-factor token))
(setq seq (cons factor seq)))
(cons token
(if (and ebnf-yac-ignore-error-recovery ebnf-yac-error)
;; ignore error recovery
nil
(ebnf-token-sequence seq)))))
;;; Factor = Name
;;; | "'" "character" "'"
;;; | "error"
;;; | "{" "C like commands" "}"
;;; .
(defun ebnf-yac-factor (token)
(cond
;; 'character'
((eq token 'terminal)
(ebnf-make-terminal ebnf-yac-lex))
;; Name
((eq token 'non-terminal)
(ebnf-make-non-terminal ebnf-yac-lex))
;; "error"
((eq token 'yac-error)
(ebnf-make-special ebnf-yac-lex))
;; not a factor
(t
nil)
))
;;; Name-List = { Name || "," }*.
(defun ebnf-yac-name-list (token)
(let (names)
(when (eq token 'non-terminal)
(while (progn
(setq names (cons ebnf-yac-lex names)
token (ebnf-yac-lex))
(eq token 'comma))
(or (eq (ebnf-yac-lex) 'non-terminal)
(error "Missing token name"))))
(cons token names)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Lexical analyzer
;;; Name = "[A-Za-z][A-Za-z0-9_.]*".
;;;
;;; Comment = "/*" "any character, but the sequence \"*/\"" "*/"
;;; | "//" "any character" "\\n".
(defconst ebnf-yac-token-table
;; control character & 8-bit character are set to `error'
(let ((table (make-vector 256 'error)))
;; upper & lower case letters:
(mapc
#'(lambda (char)
(aset table char 'non-terminal))
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
;; printable characters:
(mapc
#'(lambda (char)
(aset table char 'character))
"!#$&()*+-.0123456789=?@[\\]^_`~")
;; Override space characters:
(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 ?< 'open-angle)
(aset table ?> 'close-angle)
(aset table ?, 'comma)
(aset table ?% 'yac-pragma)
(aset table ?/ 'slash)
(aset table ?\{ 'yac-code)
(aset table ?\" 'string)
(aset table ?\' 'terminal)
(aset table ?: 'colon)
(aset table ?| 'alternative)
(aset table ?\; 'period)
table)
"Vector used to map characters to a lexical token.")
(defun ebnf-yac-initialize ()
"Initializations for Yacc/Bison parser."
(setq ebnf-yac-token-list nil))
(defun ebnf-yac-lex ()
"Lexical analyzer for Yacc/Bison.
Return a lexical token.
See documentation for variable `ebnf-yac-lex'."
(if (>= (point) ebnf-limit)
'end-of-input
(let (token)
;; skip spaces, code blocks and comments
(while (if (> (following-char) 255)
(progn
(setq token 'error)
nil)
(setq token (aref ebnf-yac-token-table (following-char)))
(cond
((or (eq token 'space)
(and ebnf-yac-skip-char
(eq token 'character)))
(ebnf-yac-skip-spaces))
((eq token 'yac-code)
(ebnf-yac-skip-code))
((eq token 'slash)
(ebnf-yac-handle-comment))
((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 "Invalid character"))
;; "string"
((eq token 'string)
(setq ebnf-yac-lex (ebnf-get-string))
'string)
;; terminal: 'char'
((eq token 'terminal)
(setq ebnf-yac-lex (ebnf-string " -&(-~" ?\' "terminal"))
'terminal)
;; non-terminal, terminal or "error"
((eq token 'non-terminal)
(setq ebnf-yac-lex (ebnf-buffer-substring "0-9A-Za-z_."))
(cond ((member ebnf-yac-lex ebnf-yac-token-list)
'terminal)
((string= ebnf-yac-lex "error")
(setq ebnf-yac-error t)
'yac-error)
(t
'non-terminal)
))
;; %% and Yacc pragmas (%TOKEN, %START, etc).
((eq token 'yac-pragma)
(forward-char)
(cond
;; Yacc separator
((eq (following-char) ?%)
(forward-char)
'yac-separator)
;; %TOKEN, %RIGHT, %LEFT, %PREC, %NONASSOC
((cdr (assoc (upcase (ebnf-buffer-substring "0-9A-Za-z_"))
'(("TOKEN" . yac-token)
("RIGHT" . yac-token)
("LEFT" . yac-token)
("NONASSOC" . yac-token)
("PREC" . yac-prec)))))
;; other Yacc pragmas
(t
'yac-pragma)
))
;; miscellaneous
(t
(forward-char)
token)
))))
(defun ebnf-yac-skip-spaces ()
(skip-chars-forward
(if ebnf-yac-skip-char
"-\n\r\t !#$&()*+,.0123456789=?@[\\\\]^_`~"
"\n\r\t ")
ebnf-limit)
(< (point) ebnf-limit))
(defconst ebnf-yac-skip-chars
"^{}/'\"\000-\010\013\016-\037\177\u0080-\u009f")
(defun ebnf-yac-skip-code ()
(forward-char)
(let ((pair 1))
(while (> pair 0)
(skip-chars-forward ebnf-yac-skip-chars ebnf-limit)
(cond
((= (following-char) ?{)
(forward-char)
(setq pair (1+ pair)))
((= (following-char) ?})
(forward-char)
(setq pair (1- pair)))
((= (following-char) ?/)
(ebnf-yac-handle-comment))
((= (following-char) ?\")
(ebnf-get-string))
((= (following-char) ?\')
(ebnf-string " -&(-~" ?\' "character"))
(t
(error "Invalid character"))
)))
(ebnf-yac-skip-spaces))
(defun ebnf-yac-handle-comment ()
(forward-char)
(cond
;; begin comment
((= (following-char) ?*)
(ebnf-yac-skip-comment)
(ebnf-yac-skip-spaces))
;; line comment
((= (following-char) ?/)
(end-of-line)
(ebnf-yac-skip-spaces))
;; no comment
(t nil)
))
(defconst ebnf-yac-comment-chars
"^*\000-\010\013\016-\037\177\u0080-\u009f")
(defun ebnf-yac-skip-comment ()
(forward-char)
(cond
;; open EPS file
((and ebnf-eps-executing (= (following-char) ?\[))
(ebnf-eps-add-context (ebnf-yac-eps-filename)))
;; close EPS file
((and ebnf-eps-executing (= (following-char) ?\]))
(ebnf-eps-remove-context (ebnf-yac-eps-filename)))
;; EPS header
((and ebnf-eps-executing (= (following-char) ?H))
(ebnf-eps-header-comment (ebnf-yac-eps-filename)))
;; EPS footer
((and ebnf-eps-executing (= (following-char) ?F))
(ebnf-eps-footer-comment (ebnf-yac-eps-filename)))
;; any other action in comment
(t
(setq ebnf-action (aref ebnf-comment-table (following-char))))
)
(let ((not-end t))
(while not-end
(skip-chars-forward ebnf-yac-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 not-end nil)))
(t
(error "Invalid character"))
))))
(defun ebnf-yac-eps-filename ()
(forward-char)
(buffer-substring-no-properties
(point)
(let ((chars (concat ebnf-yac-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)))
(t
(point))
)))
found)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(provide 'ebnf-yac)
;;; ebnf-yac.el ends here