660 lines
18 KiB
EmacsLisp
660 lines
18 KiB
EmacsLisp
;;; ebnf-abn.el --- parser for ABNF (Augmented BNF) -*- lexical-binding: t; -*-
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;; Copyright (C) 2001-2024 Free Software Foundation, Inc.
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;; Author: Vinicius Jose Latorre <viniciusjl.gnu@gmail.com>
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;; Keywords: text, ebnf, PostScript
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;; Old-Version: 1.2
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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 ABNF (Augmented BNF).
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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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;; ABNF Syntax
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;; -----------
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;;
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;; See the URL:
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;; `https://www.ietf.org/rfc/rfc2234.txt'
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;; ("Augmented BNF for Syntax Specifications: ABNF").
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;;
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;;
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;; rulelist = 1*( rule / (*c-wsp c-nl) )
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;;
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;; rule = rulename defined-as elements c-nl
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;; ; continues if next line starts with white space
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;;
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;; rulename = ALPHA *(ALPHA / DIGIT / "-")
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;;
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;; defined-as = *c-wsp ("=" / "=/") *c-wsp
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;; ; basic rules definition and incremental
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;; ; alternatives
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;;
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;; elements = alternation *c-wsp
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;;
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;; c-wsp = WSP / (c-nl WSP)
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;;
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;; c-nl = comment / CRLF
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;; ; comment or newline
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;;
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;; comment = ";" *(WSP / VCHAR) CRLF
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;;
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;; alternation = concatenation
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;; *(*c-wsp "/" *c-wsp concatenation)
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;;
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;; concatenation = repetition *(1*c-wsp repetition)
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;;
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;; repetition = [repeat] element
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;;
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;; repeat = 1*DIGIT / (*DIGIT "*" *DIGIT)
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;;
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;; element = rulename / group / option /
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;; char-val / num-val / prose-val
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;;
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;; group = "(" *c-wsp alternation *c-wsp ")"
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;;
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;; option = "[" *c-wsp alternation *c-wsp "]"
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;;
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;; char-val = DQUOTE *(%x20-21 / %x23-7E) DQUOTE
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;; ; quoted string of SP and VCHAR without DQUOTE
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;;
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;; num-val = "%" (bin-val / dec-val / hex-val)
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;;
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;; bin-val = "b" 1*BIT
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;; [ 1*("." 1*BIT) / ("-" 1*BIT) ]
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;; ; series of concatenated bit values
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;; ; or single ONEOF range
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;;
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;; dec-val = "d" 1*DIGIT
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;; [ 1*("." 1*DIGIT) / ("-" 1*DIGIT) ]
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;;
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;; hex-val = "x" 1*HEXDIG
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;; [ 1*("." 1*HEXDIG) / ("-" 1*HEXDIG) ]
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;;
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;; prose-val = "<" *(%x20-3D / %x3F-7E) ">"
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;; ; bracketed string of SP and VCHAR without
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;; ; angles
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;; ; prose description, to be used as last resort
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;;
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;; ; Core rules -- the coding depends on the system, here is used 7-bit ASCII
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;;
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;; ALPHA = %x41-5A / %x61-7A
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;; ; A-Z / a-z
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;;
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;; BIT = "0" / "1"
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;;
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;; CHAR = %x01-7F
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;; ; any 7-bit US-ASCII character, excluding NUL
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;;
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;; CR = %x0D
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;; ; carriage return
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;;
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;; CRLF = CR LF
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;; ; Internet standard newline
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;;
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;; CTL = %x00-1F / %x7F
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;; ; controls
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;;
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;; DIGIT = %x30-39
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;; ; 0-9
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;;
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;; DQUOTE = %x22
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;; ; " (Double Quote)
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;;
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;; HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
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;;
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;; HTAB = %x09
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;; ; horizontal tab
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;;
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;; LF = %x0A
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;; ; linefeed
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;;
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;; LWSP = *(WSP / CRLF WSP)
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;; ; linear white space (past newline)
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;;
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;; OCTET = %x00-FF
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;; ; 8 bits of data
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;;
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;; SP = %x20
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;; ; space
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;;
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;; VCHAR = %x21-7E
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;; ; visible (printing) characters
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;;
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;; WSP = SP / HTAB
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;; ; white space
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;;
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;;
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;; NOTES:
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;;
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;; 1. Rules name and terminal strings are case INSENSITIVE.
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;; So, the following rule names are all equals:
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;; Rule-name, rule-Name, rule-name, RULE-NAME
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;; Also, the following strings are equals:
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;; "abc", "ABC", "aBc", "Abc", "aBC", etc.
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;;
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;; 2. To have a case SENSITIVE string, use the character notation.
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;; For example, to specify the lowercase string "abc", use:
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;; %d97.98.99
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;;
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;; 3. There are no implicit spaces between elements, for example, the
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;; following rules:
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;;
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;; foo = %x61 ; a
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;;
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;; bar = %x62 ; b
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;;
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;; mumble = foo bar foo
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;;
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;; Are equivalent to the following rule:
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;;
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;; mumble = %x61.62.61
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;;
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;; If spaces are needed, it should be explicit specified, like:
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;;
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;; spaces = 1*(%x20 / %x09) ; one or more spaces or tabs
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;;
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;; mumble = foo spaces bar spaces foo
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;;
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;; 4. Lines starting with space or tab are considered a continuation line.
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;; For example, the rule:
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;;
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;; rule = foo
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;; bar
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;;
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;; Is equivalent to:
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;;
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;; rule = foo bar
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;;
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;;
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;; Differences Between ABNF And ebnf2ps ABNF
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;; -----------------------------------------
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;;
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;; Besides the characters that ABNF accepts, ebnf2ps ABNF accepts also the
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;; underscore (_) for rule name and european 8-bit accentuated characters (from
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;; \240 to \377) for rule name, string and comment.
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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-abn-lex nil
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"Value returned by `ebnf-abn-lex' function.")
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Syntactic analyzer
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;;; rulelist = 1*( rule / (*c-wsp c-nl) )
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(defun ebnf-abn-parser (start)
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"ABNF 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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rule-list token rule)
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(goto-char start)
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(setq token (ebnf-abn-lex))
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(and (eq token 'end-of-input)
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(error "Invalid ABNF file format"))
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(and (eq token 'end-of-rule)
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(setq token (ebnf-abn-lex)))
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(while (not (eq token 'end-of-input))
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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-abn-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 rule-list (cons rule rule-list))))
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(goto-char origin)
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rule-list))
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;;; rule = rulename defined-as elements c-nl
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;;; ; continues if next line starts with white space
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;;;
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;;; rulename = ALPHA *(ALPHA / DIGIT / "-")
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;;;
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;;; defined-as = *c-wsp ("=" / "=/") *c-wsp
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;;; ; basic rules definition and incremental
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;;; ; alternatives
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;;;
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;;; elements = alternation *c-wsp
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;;;
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;;; c-wsp = WSP / (c-nl WSP)
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;;;
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;;; c-nl = comment / CRLF
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;;; ; comment or newline
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;;;
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;;; comment = ";" *(WSP / VCHAR) CRLF
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(defun ebnf-abn-rule (token)
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(let ((name ebnf-abn-lex)
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(action ebnf-action)
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elements)
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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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(setq token (ebnf-abn-lex))
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(or (memq token '(equal incremental-alternative))
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(error "Invalid rule: missing `=' or `=/'"))
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(and (eq token 'incremental-alternative)
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(setq name (concat name " =/")))
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(setq elements (ebnf-abn-alternation))
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(or (memq (car elements) '(end-of-rule end-of-input))
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(error "Invalid rule: there is no end of rule"))
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(setq elements (cdr elements))
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(ebnf-eps-add-production name)
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(cons (ebnf-abn-lex)
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(ebnf-make-production name elements action))))
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;;; alternation = concatenation
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;;; *(*c-wsp "/" *c-wsp concatenation)
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(defun ebnf-abn-alternation ()
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(let (body concatenation)
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(while (eq (car (setq concatenation
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(ebnf-abn-concatenation (ebnf-abn-lex))))
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'alternative)
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(setq body (cons (cdr concatenation) body)))
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(ebnf-token-alternative body concatenation)))
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;;; concatenation = repetition *(1*c-wsp repetition)
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(defun ebnf-abn-concatenation (token)
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(let ((term (ebnf-abn-repetition token))
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seq)
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(or (setq token (car term)
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term (cdr term))
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(error "Empty element"))
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(setq seq (cons term seq))
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(while (setq term (ebnf-abn-repetition token)
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token (car term)
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term (cdr term))
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(setq seq (cons term seq)))
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(cons token
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(ebnf-token-sequence seq))))
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;;; repetition = [repeat] element
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;;;
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;;; repeat = 1*DIGIT / (*DIGIT "*" *DIGIT)
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(defun ebnf-abn-repetition (token)
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(let (lower upper)
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;; INTEGER [ "*" [ INTEGER ] ]
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(when (eq token 'integer)
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(setq lower ebnf-abn-lex
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token (ebnf-abn-lex))
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(or (eq token 'repeat)
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(setq upper lower)))
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;; "*" [ INTEGER ]
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(when (eq token 'repeat)
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;; only * ==> lower & upper are empty string
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(or lower
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(setq lower ""
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upper ""))
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(when (eq (setq token (ebnf-abn-lex)) 'integer)
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(setq upper ebnf-abn-lex
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token (ebnf-abn-lex))))
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(let ((element (ebnf-abn-element token)))
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(cond
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;; there is a repetition
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(lower
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(or element
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(error "Missing element repetition"))
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(setq token (ebnf-abn-lex))
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(cond
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;; one or more
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((and (string= lower "1") (null upper))
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(cons token (ebnf-make-one-or-more element)))
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;; zero or more
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((or (and (string= lower "0") (null upper))
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(and (string= lower "") (string= upper "")))
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(cons token (ebnf-make-zero-or-more element)))
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;; real repetition
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(t
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(ebnf-token-repeat lower (cons token element) upper))))
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;; there is an element
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(element
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(cons (ebnf-abn-lex) element))
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;; something that caller has to deal
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(t
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(cons token nil))))))
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;;; element = rulename / group / option /
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;;; char-val / num-val / prose-val
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;;;
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;;; group = "(" *c-wsp alternation *c-wsp ")"
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;;;
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;;; option = "[" *c-wsp alternation *c-wsp "]"
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;;;
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;;; char-val = DQUOTE *(%x20-21 / %x23-7E) DQUOTE
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;;; ; quoted string of SP and VCHAR without DQUOTE
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;;;
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;;; num-val = "%" (bin-val / dec-val / hex-val)
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;;;
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;;; bin-val = "b" 1*BIT
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;;; [ 1*("." 1*BIT) / ("-" 1*BIT) ]
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;;; ; series of concatenated bit values
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;;; ; or single ONEOF range
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;;;
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;;; dec-val = "d" 1*DIGIT
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;;; [ 1*("." 1*DIGIT) / ("-" 1*DIGIT) ]
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;;;
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;;; hex-val = "x" 1*HEXDIG
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;;; [ 1*("." 1*HEXDIG) / ("-" 1*HEXDIG) ]
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;;;
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;;; prose-val = "<" *(%x20-3D / %x3F-7E) ">"
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;;; ; bracketed string of SP and VCHAR without
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;;; ; angles
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;;; ; prose description, to be used as last resort
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(defun ebnf-abn-element (token)
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(cond
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;; terminal
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((eq token 'terminal)
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(ebnf-make-terminal ebnf-abn-lex))
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;; non-terminal
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((eq token 'non-terminal)
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(ebnf-make-non-terminal ebnf-abn-lex))
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;; group
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((eq token 'begin-group)
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(let ((body (ebnf-abn-alternation)))
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(or (eq (car body) 'end-group)
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(error "Missing `)'"))
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(cdr body)))
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;; optional
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((eq token 'begin-optional)
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(let ((body (ebnf-abn-alternation)))
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(or (eq (car body) 'end-optional)
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(error "Missing `]'"))
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(ebnf-token-optional (cdr body))))
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;; no element
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(t
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nil)
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))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Lexical analyzer
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(defconst ebnf-abn-token-table (make-vector 256 'error)
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"Vector used to map characters to a lexical token.")
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(defun ebnf-abn-initialize ()
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"Initialize EBNF token table."
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;; control character & control 8-bit character are set to `error'
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(let ((char ?\060))
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;; digits: 0-9
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(while (< char ?\072)
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(aset ebnf-abn-token-table char 'integer)
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(setq char (1+ char)))
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;; printable character: A-Z
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(setq char ?\101)
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(while (< char ?\133)
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(aset ebnf-abn-token-table char 'non-terminal)
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(setq char (1+ char)))
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;; printable character: a-z
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(setq char ?\141)
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(while (< char ?\173)
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(aset ebnf-abn-token-table char 'non-terminal)
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(setq char (1+ char)))
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;; European 8-bit accentuated characters:
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(setq char ?\240)
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(while (< char ?\400)
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(aset ebnf-abn-token-table char 'non-terminal)
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(setq char (1+ char)))
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;; Override end of line characters:
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(aset ebnf-abn-token-table ?\n 'end-of-rule) ; [NL] linefeed
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(aset ebnf-abn-token-table ?\r 'end-of-rule) ; [CR] carriage return
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;; Override space characters:
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(aset ebnf-abn-token-table ?\013 'space) ; [VT] vertical tab
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(aset ebnf-abn-token-table ?\t 'space) ; [HT] horizontal tab
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(aset ebnf-abn-token-table ?\ 'space) ; [SP] space
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;; Override form feed character:
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(aset ebnf-abn-token-table ?\f 'form-feed) ; [FF] form feed
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;; Override other lexical characters:
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(aset ebnf-abn-token-table ?< 'non-terminal)
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(aset ebnf-abn-token-table ?% 'terminal)
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(aset ebnf-abn-token-table ?\" 'terminal)
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(aset ebnf-abn-token-table ?\( 'begin-group)
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(aset ebnf-abn-token-table ?\) 'end-group)
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(aset ebnf-abn-token-table ?* 'repeat)
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(aset ebnf-abn-token-table ?= 'equal)
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(aset ebnf-abn-token-table ?\[ 'begin-optional)
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(aset ebnf-abn-token-table ?\] 'end-optional)
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(aset ebnf-abn-token-table ?/ 'alternative)
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;; Override comment character:
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(aset ebnf-abn-token-table ?\; 'comment)))
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(defconst ebnf-abn-non-terminal-chars
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"-_0-9A-Za-z\u00a0-\u00ff")
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(defconst ebnf-abn-non-terminal-letter-chars
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"A-Za-z\u00a0-\u00ff")
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(defun ebnf-abn-lex ()
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"Lexical analyzer for ABNF.
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Return a lexical token.
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See documentation for variable `ebnf-abn-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 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-abn-token-table (following-char)))
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(cond
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((eq token 'space)
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(skip-chars-forward " \013\t" ebnf-limit)
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(< (point) ebnf-limit))
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((eq token 'comment)
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(ebnf-abn-skip-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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((eq token 'end-of-rule)
|
||
(ebnf-abn-skip-end-of-rule))
|
||
(t nil)
|
||
)))
|
||
(cond
|
||
;; end of input
|
||
((>= (point) ebnf-limit)
|
||
'end-of-input)
|
||
;; error
|
||
((eq token 'error)
|
||
(error "Invalid character"))
|
||
;; end of rule
|
||
((eq token 'end-of-rule)
|
||
'end-of-rule)
|
||
;; integer
|
||
((eq token 'integer)
|
||
(setq ebnf-abn-lex (ebnf-buffer-substring "0-9"))
|
||
'integer)
|
||
;; terminal: "string" or %[bdx]NNN((.NNN)+|-NNN)?
|
||
((eq token 'terminal)
|
||
(setq ebnf-abn-lex
|
||
(if (= (following-char) ?\")
|
||
(ebnf-abn-string)
|
||
(ebnf-abn-character)))
|
||
'terminal)
|
||
;; non-terminal: NAME or <NAME>
|
||
((eq token 'non-terminal)
|
||
(let ((prose-p (= (following-char) ?<)))
|
||
(when prose-p
|
||
(forward-char)
|
||
(or (looking-at (concat "[" ebnf-abn-non-terminal-letter-chars "]"))
|
||
(error "Invalid prose value")))
|
||
(setq ebnf-abn-lex
|
||
(ebnf-buffer-substring ebnf-abn-non-terminal-chars))
|
||
(when prose-p
|
||
(or (= (following-char) ?>)
|
||
(error "Invalid prose value"))
|
||
(forward-char)
|
||
(setq ebnf-abn-lex (concat "<" ebnf-abn-lex ">"))))
|
||
'non-terminal)
|
||
;; equal: =, =/
|
||
((eq token 'equal)
|
||
(forward-char)
|
||
(if (/= (following-char) ?/)
|
||
'equal
|
||
(forward-char)
|
||
'incremental-alternative))
|
||
;; miscellaneous: (, ), [, ], /, *
|
||
(t
|
||
(forward-char)
|
||
token)
|
||
))))
|
||
|
||
|
||
(defun ebnf-abn-skip-end-of-rule ()
|
||
(let (eor-p)
|
||
(while (progn
|
||
;; end of rule ==> 2 or more consecutive end of lines
|
||
(setq eor-p (or (> (skip-chars-forward "\r\n" ebnf-limit) 1)
|
||
eor-p))
|
||
;; skip spaces
|
||
(skip-chars-forward " \013\t" ebnf-limit)
|
||
;; skip comments
|
||
(and (= (following-char) ?\;)
|
||
(ebnf-abn-skip-comment))))
|
||
(not eor-p)))
|
||
|
||
|
||
(defconst ebnf-abn-comment-chars
|
||
"^\n\000-\010\016-\037\177\u0080-\u009f")
|
||
|
||
|
||
(defun ebnf-abn-skip-comment ()
|
||
(forward-char)
|
||
(cond
|
||
;; open EPS file
|
||
((and ebnf-eps-executing (= (following-char) ?\[))
|
||
(ebnf-eps-add-context (ebnf-abn-eps-filename)))
|
||
;; close EPS file
|
||
((and ebnf-eps-executing (= (following-char) ?\]))
|
||
(ebnf-eps-remove-context (ebnf-abn-eps-filename)))
|
||
;; EPS header
|
||
((and ebnf-eps-executing (= (following-char) ?H))
|
||
(ebnf-eps-header-comment (ebnf-abn-eps-filename)))
|
||
;; EPS footer
|
||
((and ebnf-eps-executing (= (following-char) ?F))
|
||
(ebnf-eps-footer-comment (ebnf-abn-eps-filename)))
|
||
;; any other action in comment
|
||
(t
|
||
(setq ebnf-action (aref ebnf-comment-table (following-char)))
|
||
(skip-chars-forward ebnf-abn-comment-chars ebnf-limit))
|
||
)
|
||
;; check for a valid end of comment
|
||
(cond ((>= (point) ebnf-limit)
|
||
nil)
|
||
((= (following-char) ?\n)
|
||
t)
|
||
(t
|
||
(error "Invalid character"))
|
||
))
|
||
|
||
|
||
(defun ebnf-abn-eps-filename ()
|
||
(forward-char)
|
||
(ebnf-buffer-substring ebnf-abn-comment-chars))
|
||
|
||
|
||
(defconst ebnf-abn-string-chars
|
||
" !#-~\u00a0-\u00ff")
|
||
|
||
|
||
(defun ebnf-abn-string ()
|
||
(buffer-substring-no-properties
|
||
(progn
|
||
(forward-char)
|
||
(point))
|
||
(progn
|
||
(skip-chars-forward ebnf-abn-string-chars ebnf-limit)
|
||
(or (= (following-char) ?\")
|
||
(error "Missing `\"'"))
|
||
(prog1
|
||
(point)
|
||
(forward-char)))))
|
||
|
||
|
||
(defun ebnf-abn-character ()
|
||
;; %[bdx]NNN((-NNN)|(.NNN)+)?
|
||
(buffer-substring-no-properties
|
||
(point)
|
||
(progn
|
||
(forward-char)
|
||
(let* ((char (following-char))
|
||
(chars (cond ((or (= char ?B) (= char ?b)) "01")
|
||
((or (= char ?D) (= char ?d)) "0-9")
|
||
((or (= char ?X) (= char ?x)) "[:xdigit:]")
|
||
(t (error "Invalid terminal value")))))
|
||
(forward-char)
|
||
(or (> (skip-chars-forward chars ebnf-limit) 0)
|
||
(error "Invalid terminal value"))
|
||
(if (= (following-char) ?-)
|
||
(progn
|
||
(forward-char)
|
||
(or (> (skip-chars-forward chars ebnf-limit) 0)
|
||
(error "Invalid terminal value range")))
|
||
(while (= (following-char) ?.)
|
||
(forward-char)
|
||
(or (> (skip-chars-forward chars ebnf-limit) 0)
|
||
(error "Invalid terminal value")))))
|
||
(point))))
|
||
|
||
|
||
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
||
|
||
|
||
(provide 'ebnf-abn)
|
||
|
||
;;; ebnf-abn.el ends here
|