// sattool - visual satellite tracking and prediction tool.
// Copyright 2000 Tom Rothamel <tom-idbg@onegeek.org>
//
// 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 of the License, 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; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  

/* Parser for filter expressions */

%{
#include "sattool.h"
#include "filter.h"

#define YYPARSE_PARAM stout

void filter_error(char *);
	
extern int yylex();

%}

%union {
	char *s;
	Step *step;
}

%token <s> STR
%token AND
%token OR

%type <step> step
%type <step> level1
%type <step> level2

%%

start: level1 {
	*((Step **) stout) = $1;
}
;

level1: level2 { $$ = $1 }
| level1 OR level1 {
	$$ = new MergeStep($1, $3, merge_or);
}
;

level2: step { $$ = $1 }
| level2 AND level2 {
	$$ = new MergeStep($1, $3, merge_and);
}
;
		
step: STR '<' STR {
	$$ = GetCompareStep($1, '<', $3);
	free($1);
	free($3);
	if (!$$) YYERROR;
}
| STR '>' STR {
	$$ = GetCompareStep($1, '>', $3);
	free($1);
	free($3);
	if (!$$) YYERROR;
}
| STR '=' STR {
	$$ = GetCompareStep($1, '=', $3);
	free($1);
	free($3);
	if (!$$) YYERROR;
}
| STR {
	$$ = GetCompareStep($1, ' ', "");
	free($1);
	if (!$$) YYERROR;
}
| '(' level1 ')' { $$ = $2; }
;

%%

void filter_error(char *s) {
	error("While parsing filter expression: %s\n", s);
}