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1995-08-25
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\
\ BACKUS-NAUR FORM GRAMMAR DEFINITIONS
\
\ Copyright (C) 1990 by Mikael R.K. Patel
\
\ Computer Aided Design Laboratory (CADLAB)
\ Department of Computer and Information Science
\ Linkoping University
\ S-581 83 LINKOPING
\ SWEDEN
\
\ Email: mip@ida.liu.se
\
\ Started on: 19 February 1990
\
\ Last updated on: 21 February 1990
\
\ Dependencies:
\ (forth) forth, compiler, parser
\
\ Description:
\ Definitions for Backus-Naur Meta Language grammar. Simplifies
\ specification of grammar for the Parser Virtual Machine.
\
\ Copying:
\ This program 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 1, or (at your option)
\ any later version.
\
\ This program 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 this program; see the file COPYING. If not, write to
\ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
.( Loading Backus-Naur Form definitions...) cr
#include parser.f83
parser forth definitions
vocabulary backus-naur-form ( -- )
symbol bnf
forth compiler parser backus-naur-form definitions
\ Semantic actions for building Extended Backus-Naur Form (EBNF) grammar
variable current-syntax-symbol ( -- addr)
: first-syntax ( symbol -- )
>body dup current-syntax-symbol ! syntax
;
: next-syntax ( -- )
current-syntax-symbol @ syntax
;
: make-non-terminal ( symbol -- )
thread compile non-terminal
;
: make-terminal ( symbol -- )
thread compile terminal
;
: make-zero-or-one ( symbol -- )
thread compile zero-or-one
;
: make-zero-or-more ( symbol -- )
thread compile zero-or-more
;
: make-semantic ( symbol -- )
compile semantic thread [compile] end.syntax
;
: make-no-semantic ( -- )
compile no-semantic [compile] end.syntax
;
\ Grammar definition for Backus-Naur Form (BNF)
\
\ <bnf> ::= <head> <tail> <bnf>
\ | <eoln>
symbol head
symbol tail
bnf syntax head non-terminal tail non-terminal bnf non-terminal no-semantic end.syntax
bnf syntax eoln non-terminal no-semantic end.syntax
\ <head> ::= <factor> ::= @ first-syntax
\ | | @ next-syntax
symbol factor
symbol :
symbol =
symbol |
head syntax factor non-terminal : terminal : terminal = terminal semantic first-syntax end.syntax
head syntax | terminal semantic next-syntax end.syntax
\ <tail> ::= ' @ <entry> @ make-semantic
\ | <term> <tail>
\ | <empty> @ make-no-semantic
symbol @
symbol term
tail syntax @ terminal entry non-terminal semantic make-semantic end.syntax
tail syntax term non-terminal tail non-terminal no-semantic end.syntax
tail syntax empty non-terminal semantic make-no-semantic end.syntax
\ <term> ::= [ <factor> ] @ make-zero-or-one
\ | { <factor> } @ make-zero-or-more
\ | ' ' <entry> @ make-terminal
\ | <factor> @ make-non-terminal
\ | <entry> @ make-terminal
symbol [
symbol ]
symbol {
symbol }
symbol '
term syntax [ terminal factor non-terminal ] terminal semantic make-zero-or-one end.syntax
term syntax { terminal factor non-terminal } terminal semantic make-zero-or-more end.syntax
term syntax ' terminal entry non-terminal semantic make-terminal end.syntax
term syntax factor non-terminal semantic make-non-terminal end.syntax
term syntax entry non-terminal semantic make-terminal end.syntax
\ <factor> ::= ' < <entry> >
symbol <
symbol >
factor syntax < terminal entry non-terminal > terminal no-semantic end.syntax
forth only