added skeleton rules and grammar to bison file

grammar.y

@@ -10,7 +10,8 @@
   extern char* yytext;
   extern int yychar;
   SymbolTable * st;
-  
+  char* cur_value;
+  char* cur_type;
 %}
 
 %token ID 101
@@ -61,12 +62,122 @@
 %token COMMENT 700
 %%
 
-start: /*empty for now*/
-	OPTIONAL;
+program: 
+	prototype_or_definition_list;
 
-OPTIONAL:
-	L_BRACKET		{printf("success");};
+prototype_or_definition_list:
+	prototype prototype_or_definition_list
+	| definition prototype_or_definition_list
+	| prototype
+	| definition
+	;
+prototype:
+	L_PAREN EXTERNAL R_PAREN FUNCTION ID COLON ID;
 
+definition:
+	TYPE ID COLON dblock
+	| TYPE ID COLON constant ARROW ID
+	| TYPE ID COLON ID ARROW ID
+	| ID parameter ASSIGN sblock
+	;
+
+parameter:
+	L_PAREN ID R_PAREN
+	| AS L_PAREN idlist R_PAREN
+	;
+
+idlist:
+	ID COMMA idlist
+	|ID
+	;
+
+sblock:
+	L_BRACE {st = CreateScope(st,1,1);} statement_list {st = getParent(st);} R_BRACE
+	| L_BRACE {st = CreateScope(st,1,1);} dblock statement_list {st = getParent(st);} R_BRACE
+	;
+
+dblock:
+	L_BRACKET declaration_list R_BRACKET;
+
+declaration_list:
+	declaration {CreateEntry(st,cur_type,cur_value);} SEMI_COLON declaration_list
+	| declaration {CreateEntry(st,cur_type,cur_value);}
+	;
+
+declaration:
+	ID COLON ID {cur_value = strdup($1);cur_type = strdup($3);};
+
+statement_list:
+	compound_statement statement_list
+	| compound_statement
+	| simple_statement SEMI_COLON statement_list
+	| simple_statement SEMI_COLON
+	;
+
+compound_statement:
+	WHILE L_PAREN expression R_PAREN sblock
+	| IF L_PAREN expression R_PAREN THEN sblock ELSE sblock
+	| sblock
+	;
+
+simple_statement:
+	assignable ASSIGN expression
+	| RETURN expression
+	;
+
+assignable:
+	ID
+	| assignable ablock
+	| assignable DOT ID
+	;
+
+expression:
+	constant
+	| UnaryOperator expression
+	| assignable
+	| expression binaryOperator expression
+	| L_PAREN expression R_PAREN
+	| memOp assignable
+	;
+
+ablock:
+	L_PAREN argument_list R_PAREN;
+
+argument_list:
+	expression COMMA argument_list
+	| expression
+	;
+
+UnaryOperator:
+	SUB_OR_NEG
+	| NOT
+	;
+
+memOp:
+	RESERVE
+	| RELEASE
+	;
+
+binaryOperator:
+	ADD
+	| SUB_OR_NEG
+	| MUL
+	| DIV
+	| REM
+	| AND
+	| OR
+	| LESS_THAN
+	| EQUAL_TO
+	;
+
+constant:
+	C_STRING
+	| C_INTEGER
+	| C_NULL
+	| C_CHARACTER
+	| C_TRUE
+	| C_FALSE
+	;
 //
 %%
 
@@ -75,11 +186,13 @@ void yyerror(const char *err) {
 }
 
 int main() {
+	cur_value[1] = "";
+	cur_type[1] = "";
 	st=CreateScope(NULL,1,1);
 	int a;
 	while ((a = yyparse()) != EOF){
 		printf("%d = a: yytext = %s: yychar = %d\n", a, yytext, yychar);
-		if(yytext[0] == '!'){
+		if(yytext[0] == '?'){
 			print_symbol_table(getAncestor(st),stdout);
 			break;
 		}