diff --git a/.vscode/settings.json b/.vscode/settings.json
index 25afd79..c8e22fd 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -2,5 +2,13 @@
     "clangd.arguments": [
         "--compile-commands-dir=${workspaceFolder}/build"
     ],
-    "cmake.configureOnOpen": true
+    "cmake.configureOnOpen": true,
+    "antlr4.rrd.saveDir": "${workspaceFolder}/build",
+    "antlr4.atn.saveDir": "${workspaceFolder}/build",
+    "antlr4.generation": {
+        "mode": "internal",
+        "language": "C++",
+        "listeners": false,
+        "visitors": true
+    }
 }
\ No newline at end of file
diff --git a/SysY.g4 b/SysY.g4
index dc1fb33..8320d48 100644
--- a/SysY.g4
+++ b/SysY.g4
@@ -14,7 +14,7 @@ decl
    ;
 
 constDecl
-   : CONST_KW bType constDef (COMMA constDef)* SEMICOLON
+   : CONST_KW bType constDef (COMMA constDef)* ';'
    ;
 
 bType
@@ -31,7 +31,7 @@ constInitVal
    ;
 
 varDecl
-   : bType varDef (COMMA varDef)* SEMICOLON
+   : bType varDef (COMMA varDef)* ';'
    ;
 
 varDef
@@ -82,11 +82,11 @@ stmt
    ;
 
 assignStmt
-   : lVal ASSIGN exp SEMICOLON
+   : lVal '=' exp ';'
    ;
 
 expStmt
-   : exp? SEMICOLON
+   : exp? ';'
    ;
 
 conditionStmt
@@ -98,15 +98,15 @@ whileStmt
    ;
 
 breakStmt
-   : BREAK_KW SEMICOLON
+   : BREAK_KW ';'
    ;
 
 continueStmt
-   : CONTINUE_KW SEMICOLON
+   : CONTINUE_KW ';'
    ;
 
 returnStmt
-   : RETURN_KW (exp)? SEMICOLON
+   : RETURN_KW (exp)? ';'
    ;
 
 exp
@@ -148,8 +148,8 @@ callee
    ;
 
 unaryOp
-   : PLUS
-   | MINUS
+   : '+'
+   | '-'
    | NOT
    ;
 
@@ -177,8 +177,8 @@ addExp
    ; // eliminate left-recursive
    
 addOp
-   : PLUS
-   | MINUS
+   : '+'
+   | '-'
    ;
 
 relExp
@@ -280,14 +280,6 @@ fragment ESC
    : '\\"' | '\\\\'
    ;
 
-PLUS
-   : '+'
-   ;
-
-MINUS
-   : '-'
-   ;
-
 NOT
    : '!'
    ;