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515 lines
13 KiB
EmacsLisp
515 lines
13 KiB
EmacsLisp
;;; ebnf-yac.el --- parser for Yacc/Bison
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;; Copyright (C) 1999-2019 Free Software Foundation, Inc.
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;; Author: Vinicius Jose Latorre <viniciusjl.gnu@gmail.com>
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;; Keywords: wp, ebnf, PostScript
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;; Old-Version: 1.4
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;; Package: ebnf2ps
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;
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;;
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;; This is part of ebnf2ps package.
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;;
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;; This package defines a parser for Yacc/Bison.
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;;
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;; See ebnf2ps.el for documentation.
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;;
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;;
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;; Yacc/Bison Syntax
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;; -----------------
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;;
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;; YACC = { YACC-Definitions }* "%%" { YACC-Rule }* [ "%%" [ YACC-Code ] ].
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;;
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;; YACC-Definitions = ( "%token" | "%left" | "%right" | "%nonassoc" )
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;; [ "<" Name ">" ] Name-List
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;; | "%prec" Name
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;; | "any other Yacc definition"
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;; .
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;;
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;; YACC-Code = "any C definition".
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;;
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;; YACC-Rule = Name ":" Alternative ";".
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;;
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;; Alternative = { Sequence || "|" }*.
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;;
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;; Sequence = { Factor }*.
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;;
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;; Factor = Name
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;; | "'" "character" "'"
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;; | "error"
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;; | "{" "C like commands" "}"
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;; .
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;;
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;; Name-List = { Name || "," }*.
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;;
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;; Name = "[A-Za-z][A-Za-z0-9_.]*".
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;;
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;; Comment = "/*" "any character, but the sequence \"*/\"" "*/"
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;; | "//" "any character, but the newline \"\\n\"" "\\n".
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;;
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;;
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;; In other words, a valid Name begins with a letter (upper or lower case)
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;; followed by letters, decimal digits, underscore (_) or point (.). For
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;; example: this_is_a_valid.name, Another_EXAMPLE, mIxEd.CaSe.
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;;
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;;
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;; Acknowledgments
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;; ---------------
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;;
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;; Thanks to Matthew K. Junker <junker@alum.mit.edu> for the suggestion to deal
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;; with %right, %left and %prec pragmas. His suggestion was extended to deal
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;; with %nonassoc pragma too.
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;;
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;;
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;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; Code:
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(require 'ebnf-otz)
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(defvar ebnf-yac-lex nil
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"Value returned by `ebnf-yac-lex' function.")
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(defvar ebnf-yac-token-list nil
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"List of `%TOKEN' names.")
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(defvar ebnf-yac-skip-char nil
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"Non-nil means skip printable characters with no grammatical meaning.")
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(defvar ebnf-yac-error nil
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"Non-nil means \"error\" occurred.")
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Syntactic analyzer
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;;; YACC = { YACC-Definitions }* "%%" { YACC-Rule }* [ "%%" [ YACC-Code ] ].
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;;;
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;;; YACC-Code = "any C definition".
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(defun ebnf-yac-parser (start)
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"yacc/Bison parser."
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(let ((total (+ (- ebnf-limit start) 1))
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(bias (1- start))
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(origin (point))
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syntax-list token rule)
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(goto-char start)
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(setq token (ebnf-yac-lex))
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(and (eq token 'end-of-input)
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(error "Invalid Yacc/Bison file format"))
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(or (eq (ebnf-yac-definitions token) 'yac-separator)
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(error "Missing `%%%%'"))
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(setq token (ebnf-yac-lex))
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(while (not (memq token '(end-of-input yac-separator)))
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(ebnf-message-float
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"Parsing...%s%%"
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(/ (* (- (point) bias) 100.0) total))
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(setq token (ebnf-yac-rule token)
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rule (cdr token)
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token (car token))
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(or (ebnf-add-empty-rule-list rule)
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(setq syntax-list (cons rule syntax-list))))
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(goto-char origin)
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syntax-list))
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;;; YACC-Definitions = ( "%token" | "%left" | "%right" | "%nonassoc" )
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;;; [ "<" Name ">" ] Name-List
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;;; | "%prec" Name
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;;; | "any other Yacc definition"
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;;; .
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(defun ebnf-yac-definitions (token)
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(let ((ebnf-yac-skip-char t))
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(while (not (memq token '(yac-separator end-of-input)))
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(setq token
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(cond
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;; ( "%token" | "%left" | "%right" | "%nonassoc" )
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;; [ "<" Name ">" ] Name-List
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((eq token 'yac-token)
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(setq token (ebnf-yac-lex))
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(when (eq token 'open-angle)
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(or (eq (ebnf-yac-lex) 'non-terminal)
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(error "Missing type name"))
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(or (eq (ebnf-yac-lex) 'close-angle)
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(error "Missing `>'"))
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(setq token (ebnf-yac-lex)))
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(setq token (ebnf-yac-name-list token)
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ebnf-yac-token-list (nconc (cdr token)
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ebnf-yac-token-list))
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(car token))
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;; "%prec" Name
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((eq token 'yac-prec)
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(or (eq (ebnf-yac-lex) 'non-terminal)
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(error "Missing prec name"))
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(ebnf-yac-lex))
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;; "any other Yacc definition"
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(t
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(ebnf-yac-lex))
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)))
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token))
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;;; YACC-Rule = Name ":" Alternative ";".
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(defun ebnf-yac-rule (token)
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(let ((header ebnf-yac-lex)
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(action ebnf-action)
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body)
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(setq ebnf-action nil)
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(or (eq token 'non-terminal)
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(error "Invalid rule name"))
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(or (eq (ebnf-yac-lex) 'colon)
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(error "Invalid rule: missing `:'"))
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(setq body (ebnf-yac-alternative))
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(or (eq (car body) 'period)
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(error "Invalid rule: missing `;'"))
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(setq body (cdr body))
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(ebnf-eps-add-production header)
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(cons (ebnf-yac-lex)
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(ebnf-make-production header body action))))
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;;; Alternative = { Sequence || "|" }*.
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(defun ebnf-yac-alternative ()
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(let (body sequence)
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(while (eq (car (setq sequence (ebnf-yac-sequence)))
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'alternative)
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(and (setq sequence (cdr sequence))
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(setq body (cons sequence body))))
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(ebnf-token-alternative body sequence)))
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;;; Sequence = { Factor }*.
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(defun ebnf-yac-sequence ()
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(let (ebnf-yac-error token seq factor)
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(while (setq token (ebnf-yac-lex)
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factor (ebnf-yac-factor token))
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(setq seq (cons factor seq)))
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(cons token
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(if (and ebnf-yac-ignore-error-recovery ebnf-yac-error)
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;; ignore error recovery
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nil
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(ebnf-token-sequence seq)))))
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;;; Factor = Name
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;;; | "'" "character" "'"
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;;; | "error"
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;;; | "{" "C like commands" "}"
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;;; .
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(defun ebnf-yac-factor (token)
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(cond
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;; 'character'
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((eq token 'terminal)
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(ebnf-make-terminal ebnf-yac-lex))
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;; Name
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((eq token 'non-terminal)
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(ebnf-make-non-terminal ebnf-yac-lex))
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;; "error"
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((eq token 'yac-error)
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(ebnf-make-special ebnf-yac-lex))
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;; not a factor
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(t
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nil)
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))
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;;; Name-List = { Name || "," }*.
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(defun ebnf-yac-name-list (token)
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(let (names)
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(when (eq token 'non-terminal)
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(while (progn
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(setq names (cons ebnf-yac-lex names)
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token (ebnf-yac-lex))
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(eq token 'comma))
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(or (eq (ebnf-yac-lex) 'non-terminal)
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(error "Missing token name"))))
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(cons token names)))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Lexical analyzer
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;;; Name = "[A-Za-z][A-Za-z0-9_.]*".
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;;;
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;;; Comment = "/*" "any character, but the sequence \"*/\"" "*/"
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;;; | "//" "any character" "\\n".
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(defconst ebnf-yac-token-table
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;; control character & 8-bit character are set to `error'
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(let ((table (make-vector 256 'error)))
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;; upper & lower case letters:
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(mapc
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#'(lambda (char)
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(aset table char 'non-terminal))
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
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;; printable characters:
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(mapc
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#'(lambda (char)
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(aset table char 'character))
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"!#$&()*+-.0123456789=?@[\\]^_`~")
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;; Override space characters:
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(aset table ?\n 'space) ; [NL] linefeed
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(aset table ?\r 'space) ; [CR] carriage return
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(aset table ?\t 'space) ; [HT] horizontal tab
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(aset table ?\ 'space) ; [SP] space
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;; Override form feed character:
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(aset table ?\f 'form-feed) ; [FF] form feed
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;; Override other lexical characters:
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(aset table ?< 'open-angle)
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(aset table ?> 'close-angle)
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(aset table ?, 'comma)
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(aset table ?% 'yac-pragma)
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(aset table ?/ 'slash)
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(aset table ?\{ 'yac-code)
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(aset table ?\" 'string)
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(aset table ?\' 'terminal)
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(aset table ?: 'colon)
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(aset table ?| 'alternative)
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(aset table ?\; 'period)
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table)
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"Vector used to map characters to a lexical token.")
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(defun ebnf-yac-initialize ()
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"Initializations for Yacc/Bison parser."
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(setq ebnf-yac-token-list nil))
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(defun ebnf-yac-lex ()
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"Lexical analyzer for Yacc/Bison.
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Return a lexical token.
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See documentation for variable `ebnf-yac-lex'."
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(if (>= (point) ebnf-limit)
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'end-of-input
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(let (token)
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;; skip spaces, code blocks and comments
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(while (if (> (following-char) 255)
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(progn
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(setq token 'error)
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nil)
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(setq token (aref ebnf-yac-token-table (following-char)))
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(cond
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((or (eq token 'space)
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(and ebnf-yac-skip-char
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(eq token 'character)))
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(ebnf-yac-skip-spaces))
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((eq token 'yac-code)
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(ebnf-yac-skip-code))
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((eq token 'slash)
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(ebnf-yac-handle-comment))
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((eq token 'form-feed)
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(forward-char)
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(setq ebnf-action 'form-feed))
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(t nil)
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)))
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(cond
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;; end of input
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((>= (point) ebnf-limit)
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'end-of-input)
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;; error
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((eq token 'error)
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(error "Invalid character"))
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;; "string"
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((eq token 'string)
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(setq ebnf-yac-lex (ebnf-get-string))
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'string)
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;; terminal: 'char'
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((eq token 'terminal)
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(setq ebnf-yac-lex (ebnf-string " -&(-~" ?\' "terminal"))
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'terminal)
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;; non-terminal, terminal or "error"
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((eq token 'non-terminal)
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(setq ebnf-yac-lex (ebnf-buffer-substring "0-9A-Za-z_."))
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(cond ((member ebnf-yac-lex ebnf-yac-token-list)
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'terminal)
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((string= ebnf-yac-lex "error")
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(setq ebnf-yac-error t)
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'yac-error)
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(t
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'non-terminal)
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))
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;; %% and Yacc pragmas (%TOKEN, %START, etc).
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((eq token 'yac-pragma)
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(forward-char)
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(cond
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;; Yacc separator
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((eq (following-char) ?%)
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(forward-char)
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'yac-separator)
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;; %TOKEN, %RIGHT, %LEFT, %PREC, %NONASSOC
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((cdr (assoc (upcase (ebnf-buffer-substring "0-9A-Za-z_"))
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'(("TOKEN" . yac-token)
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("RIGHT" . yac-token)
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("LEFT" . yac-token)
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("NONASSOC" . yac-token)
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("PREC" . yac-prec)))))
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;; other Yacc pragmas
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(t
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'yac-pragma)
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))
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;; miscellaneous
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(t
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(forward-char)
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token)
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))))
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(defun ebnf-yac-skip-spaces ()
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(skip-chars-forward
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(if ebnf-yac-skip-char
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"-\n\r\t !#$&()*+,.0123456789=?@[\\\\]^_`~"
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"\n\r\t ")
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ebnf-limit)
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(< (point) ebnf-limit))
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;; replace the range "\177-\377" (see `ebnf-range-regexp').
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(defconst ebnf-yac-skip-chars
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(ebnf-range-regexp "^{}/'\"\000-\010\013\016-\037" ?\177 ?\377))
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(defun ebnf-yac-skip-code ()
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(forward-char)
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(let ((pair 1))
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(while (> pair 0)
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(skip-chars-forward ebnf-yac-skip-chars ebnf-limit)
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(cond
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((= (following-char) ?{)
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(forward-char)
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(setq pair (1+ pair)))
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((= (following-char) ?})
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(forward-char)
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(setq pair (1- pair)))
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((= (following-char) ?/)
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(ebnf-yac-handle-comment))
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((= (following-char) ?\")
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(ebnf-get-string))
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((= (following-char) ?\')
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(ebnf-string " -&(-~" ?\' "character"))
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(t
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(error "Invalid character"))
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)))
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(ebnf-yac-skip-spaces))
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(defun ebnf-yac-handle-comment ()
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(forward-char)
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(cond
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;; begin comment
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((= (following-char) ?*)
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(ebnf-yac-skip-comment)
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(ebnf-yac-skip-spaces))
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;; line comment
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((= (following-char) ?/)
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(end-of-line)
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(ebnf-yac-skip-spaces))
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;; no comment
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(t nil)
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))
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;; replace the range "\177-\237" (see `ebnf-range-regexp').
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(defconst ebnf-yac-comment-chars
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(ebnf-range-regexp "^*\000-\010\013\016-\037" ?\177 ?\237))
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(defun ebnf-yac-skip-comment ()
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(forward-char)
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(cond
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;; open EPS file
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((and ebnf-eps-executing (= (following-char) ?\[))
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(ebnf-eps-add-context (ebnf-yac-eps-filename)))
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;; close EPS file
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((and ebnf-eps-executing (= (following-char) ?\]))
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(ebnf-eps-remove-context (ebnf-yac-eps-filename)))
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;; EPS header
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((and ebnf-eps-executing (= (following-char) ?H))
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(ebnf-eps-header-comment (ebnf-yac-eps-filename)))
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;; EPS footer
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((and ebnf-eps-executing (= (following-char) ?F))
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(ebnf-eps-footer-comment (ebnf-yac-eps-filename)))
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;; any other action in comment
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(t
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(setq ebnf-action (aref ebnf-comment-table (following-char))))
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)
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(let ((not-end t))
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(while not-end
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(skip-chars-forward ebnf-yac-comment-chars ebnf-limit)
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(cond ((>= (point) ebnf-limit)
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(error "Missing end of comment: `*/'"))
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((= (following-char) ?*)
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(skip-chars-forward "*" ebnf-limit)
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(when (= (following-char) ?/)
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;; end of comment
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(forward-char)
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(setq not-end nil)))
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(t
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(error "Invalid character"))
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))))
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(defun ebnf-yac-eps-filename ()
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(forward-char)
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(buffer-substring-no-properties
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(point)
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(let ((chars (concat ebnf-yac-comment-chars "\n"))
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found)
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(while (not found)
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(skip-chars-forward chars ebnf-limit)
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(setq found
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(cond ((>= (point) ebnf-limit)
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(point))
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((= (following-char) ?*)
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(skip-chars-forward "*" ebnf-limit)
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(if (/= (following-char) ?\/)
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nil
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(backward-char)
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(point)))
|
||
(t
|
||
(point))
|
||
)))
|
||
found)))
|
||
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
||
|
||
(provide 'ebnf-yac)
|
||
|
||
|
||
;;; ebnf-yac.el ends here
|