add tag4stmt in .g4,format cpp modification needed

src/SysY.g4

@@ -136,29 +136,29 @@ blockStmt: LBRACE blockItem* RBRACE;
 
 blockItem: decl | stmt;
 
-stmt: lValue ASSIGN exp SEMICOLON
-		| exp? SEMICOLON
-		| blockStmt
-		| IF LPAREN cond RPAREN stmt (ELSE stmt)?
-		| WHILE LPAREN cond RPAREN stmt
-		| BREAK SEMICOLON
-		| CONTINUE SEMICOLON
-		| RETURN exp? SEMICOLON;
+stmt: lValue ASSIGN exp SEMICOLON					#assignStmt
+		| exp? SEMICOLON							#expStmt
+		| blockStmt									#blkStmt
+		| IF LPAREN cond RPAREN stmt (ELSE stmt)?	#ifStmt
+		| WHILE LPAREN cond RPAREN stmt				#whileStmt
+		| BREAK SEMICOLON							#breakStmt
+		| CONTINUE SEMICOLON						#continueStmt
+		| RETURN exp? SEMICOLON						#returnStmt;
 
 exp: addExp;
 cond: lOrExp;
 lValue: Ident (LBRACK exp RBRACK)*;
 
 // 为了方便测试 primaryExp 可以是一个string
-primaryExp: LPAREN exp RPAREN
-			| lValue
-			| number
-			| string;
+primaryExp: LPAREN exp RPAREN						#parenExp
+			| lValue								#lVal
+			| number								#num
+			| string								#str;
 
 number: ILITERAL | FLITERAL;
-unaryExp: primaryExp
-			| Ident LPAREN (funcRParams)? RPAREN
-			| unaryOp unaryExp;
+unaryExp: primaryExp								#primExp
+			| Ident LPAREN (funcRParams)? RPAREN	#call
+			| unaryOp unaryExp						#unExp;
 
 unaryOp: ADD|SUB|NOT;
 funcRParams: exp (COMMA exp)*;