set up grammar structure

grammar/MXParser.g4

@@ -3,39 +3,74 @@ parser grammar MXParser;
 options { tokenVocab=MXLexer; }
 
 mxprog
-    : function* EOF
+    : (class_def|define_statement|function_def)+ EOF
     ;
 
-function
-    : type ID LPAREN RPAREN block
+function_def
+    : type ID LPAREN ((type ID)(COMMA type ID)*)? RPAREN suite
     ;
 
+class_def : CLASS ID LBRACE (class_var_def|class_constructor|function_def)* RBRACE SEMICOLON;
+class_var_def : type (LBRACKET RBRACKET)* ID (COMMA ID )* SEMICOLON;
+class_constructor : ID LPAREN RPAREN suite;
+suite : LBRACE statement* RBRACE;
+statement
+    : SEMICOLON
+    | define_statement
+    | expr SEMICOLON
+    | IF LPAREN expr RPAREN statement (ELSE statement)?
+    | WHILE LPAREN expr RPAREN statement
+    | FOR LPAREN (define_statement|(expr SEMICOLON)|SEMICOLON) expr? SEMICOLON (define_statement|expr)? RPAREN statement
+    | (BREAK|CONTINUE|(RETURN expr?)) SEMICOLON
+    | suite
+    ;
+define_statement : type (LBRACKET RBRACKET)* ID (ASSIGN expr)? (COMMA ID (ASSIGN expr)?)* SEMICOLON;
+expr
+    : basic_expr
+    | LPAREN expr RPAREN
+    | expr DOT (ID|(ID LPAREN (expr (COMMA expr)*)? RPAREN))
+    | expr (LBRACKET expr RBRACKET)+
+    | expr (SELF_PLUS | SELF_MINUS)
+    | (SELF_PLUS | SELF_MINUS) expr
+    | MINUS expr
+    | LNOT expr
+    | BNOT expr
+    | expr (MULTIPLY|DIVIDE|MOD) expr
+    | expr (PLUS|MINUS) expr
+    | expr (ARS|ALS) expr
+    | expr (GN|GE|LN|LE) expr
+    | expr (NE|EQ) expr
+    | expr BAND expr
+    | expr BXOR expr
+    | expr BOR expr
+    | expr LAND expr
+    | expr LOR expr
+    | expr QUESTION_MARK expr COLON expr
+    | <assoc=right> expr ASSIGN expr
+    | NEW ID
+    | NEW ID LPAREN RPAREN
+    | NEW ID (LBRACKET expr RBRACKET)*(LBRACKET RBRACKET)*constant?
+    ;
+
+basic_expr
+    : THIS
+    | ID
+    | ID LPAREN (expr (COMMA expr)*)? RPAREN
+    | formatted_string
+    | constant
+    ;
+
+formatted_string : FORMAT_STRING_WHOLE | (FORMAT_STRING_HEAD expr (FORMAT_STRING_BODY expr)*? FORMAT_STRING_TAIL);
+constant : TRUE
+          |FALSE
+          |INT_LITERAL
+          |STRING_LITERAL
+          |NULL
+          |LBRACE (constant (COMMA constant)*)? RBRACE;
 type
     : INT
+    | BOOL
+    | STRING
     | VOID
-    ;
-
-block
-    : LBRACE statement* RBRACE
-    ;
-
-statement
-    : expression SEMICOLON
-    | returnStmt
-    | ifStmt
-    ;
-
-expression
-    : INT_LITERAL
     | ID
-    | expression (PLUS | MINUS | MULTIPLY | DIVIDE) expression
-    | LPAREN expression RPAREN
-    ;
-
-returnStmt
-    : RETURN expression? SEMICOLON
-    ;
-
-ifStmt
-    : IF LPAREN expression RPAREN statement (ELSE statement)?
-    ;
+    ;