%{
	#include <stdio.h>
	#include <stdlib.h>
%}

%start Program
%token STRUCT END METHOD VAR IF THEN ELSE WHILE DO RETURN NOT OR THIS
%token IDENT NUM ASSIGN

%%

Program:
	  Methoddef ';' Program
	| Structdef ';' Program
	|
	;

Structdef:
	  STRUCT Idents END
	;

Methoddef:
	  METHOD IDENT '(' Idents ')' Statseq END
	;

Idents:
	  IDENT Idents
	|
	;

Statseq:
	  Statement ';' Statseq
	|
	;

Statement:
	  Lexpr ASSIGN Expr
	| VAR IDENT ASSIGN Expr
	| Expr
	| IF Expr THEN Statseq END
	| IF Expr THEN Statseq ELSE Statseq END
	| WHILE Expr DO Statseq END
	| RETURN Expr
	;

Lexpr:
	  IDENT
	| Term '.' IDENT
	;

Expr:
	  Term
	| NOT Term
	| Term Plusterm
	| Term Multerm
	| Term Orterm
	| Term '<' Term
	| Term '=' Term
	;

Plusterm:
	  '+' Term Plusterm
	| '+' Term
	;

Multerm:
	  '*' Term Multerm
	| '*' Term
	;

Orterm:
	  OR Term Orterm
	| OR Term
	;


Term:
	  '(' Expr ')'
	| NUM
	| '-' NUM
	| THIS
	| IDENT
	| Term '.' IDENT
	| Methcall
	;

Methcall:
	  IDENT '(' Exprs ')'
	| Term '.' IDENT '(' Exprs ')'
	;

Exprs:
	  Expr
	| Exprs ',' Expr
	;

%%

extern int yylex();
extern int yylineno;

int yyerror(char *error_text)
{
	fprintf(stderr,"Line %i: %s\n", yylineno, error_text);
	exit(2);
}

int main(int argc, char **argv)
{
	#if 0
	yydebug=1;
	#endif
	yyparse();
	return 0;
}