;;; wisent-calc.wy --- Grammar of the infix notation calculator

;; Copyright (C) 2002, 2003 David Ponce

;; Author: David Ponce <david@dponce.com>
;; Maintainer: David Ponce <david@dponce.com>
;; Created: 19 Feb 2002
;; Keywords: syntax
;; X-RCS: $Id: wisent-calc.wy,v 1.8 2005/09/30 20:23:00 zappo Exp $

;; This file is not part of GNU Emacs.

;; 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 2, 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, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:
;;
;; This is a port of the Bison 1.28d Infix Calc sample program to the
;; Elisp LALR parser Wisent.  It illustrates usage of operator
;; precedence and contextual precedence.  Implementation is in the
;; file wisent-calc.el.

;;; History:
;; 

;;%package wisent-calc-wy

%token <number> NUM

%nonassoc '=' ;; comparison
%left '-' '+'
%left '*' '/'
%left NEG     ;; negation--unary minus
%right '^'    ;; exponentiation

%%

input:
    line
  | input line
    (format "%s %s" $1 $2)
  ;

line:
    ';'
    {";"}
  | exp ';'
    (format "%s;" $1)
  | error ';'
    {"Error;"}
  ;

exp:
    NUM
    (string-to-number $1)
  | exp '=' exp
    (= $1 $3)
  | exp '+' exp
    (+ $1 $3)
  | exp '-' exp
    (- $1 $3)
  | exp '*' exp
    (* $1 $3)
  | exp '/' exp
    (/ $1 $3)
  | '-' exp %prec NEG
    (- $2)
  | exp '^' exp
    (expt $1 $3)
  | '(' exp ')'
    {$2}
  ;

%%

(defun wisent-calc-setup-parser ()
  "Setup buffer for parse."
  (wisent-calc-wy--install-parser)
  (setq semantic-number-expression
        (concat "\\([0-9]+\\([.][0-9]*\\)?\\([eE][-+]?[0-9]+\\)?"
                "\\|[.][0-9]+\\([eE][-+]?[0-9]+\\)?\\)")
        semantic-lex-analyzer 'wisent-calc-lexer
        semantic-lex-depth nil
        semantic-lex-syntax-modifications
        '((?\; ".") (?\= ".") (?\+ ".")
          (?\- ".") (?\* ".") (?\/ ".")
          (?\^ ".") (?\( ".") (?\) ".")
          )
        )
  )

;;; wisent-calc.wy ends here