parsing - 文法パーサーの提案 (ANTLR)

Question

さて、私は Antlr4 で簡単な QBasic 文法を書こうとしています。また、「Else-If」ループは正しく機能せず、自動的にassigncommandafterに変換されTHENます。そして、私の文法を見直していただけますか、改善点はありますか?

正規表現での書き方string（キリル文字も）

これらのキーワード ( 'PRINT' 'IF') を書くべきですか? またはレクサーを使用します（のように..PRINTKEY; PRINTKEY : 'PRINT'）

grammar Hello3;

// AssignCommand; MainCommand; FlowCommand
prog : (assigncommand | maincommand | flowcommand)+;

// AssignInt; AssignString
// MyAge = PreviousAge + 1
// MyName$ = FirstName$ + MiddleName$ + LastName$
assigncommand : assignint | assignstring;
assignint : IDINT '=' (IDINT | INT) (OPERATORMATH (IDINT | INT))* '\n'+;
assignstring : IDSTRING '=' (IDSTRING | STRING) ('+' (IDSTRING | STRING))* '\n'+;

//PrintCommand, InputCommand
//PRINT MyName$, MyAge, "Hello", 123
//INPUT "What is your name?", yourname$
//(or)INPUT yourname$ 
maincommand : printcommand | inputcommand;
printcommand : 'PRINT' (',' (IDINT | IDSTRING | STRING | INT))+ '\n'+;
inputcommand : 'INPUT' (IDINT | IDSTRING | STRING)? ',' (IDINT | IDSTRING) '\n'+;


//If-ElseFlow; WhileFlow
//If-Else-Add; Else-Add
//
//IF a > 3 THEN
//PRINT a
//a = a -1
//ELSE IF a = 1 THEN
//b = a
//END IF
//
//WHILE a > 3
//a = a - 1
//PRINT a
//WEND
flowcommand : ifelseflow | whileflow;
ifelseflow : 'IF' conditionflow 'THEN' '\n' ifelseadd* elseadd* 'END' 'IF' '\n'+;
whileflow : 'WHILE' conditionflow '\n' (assigncommand | maincommand | flowcommand)*  'WEND' '\n'+;

conditionflow : ((INT | IDINT) OPERATORBOOL (INT | IDINT)) | ((STRING | IDSTRING) '=' (STRING | IDSTRING));
ifelseadd : 'ELSEIF' conditionflow 'THEN' '\n' ((assigncommand | maincommand | flowcommand) '\n')+;
elseadd : 'ELSE' '\n' ((assigncommand | maincommand | flowcommand) '\n')+;

//Lexers
INT : [0-9]+;
STRING : '"' [a-zA-Z\u0400-\u04FF\0-9' ''?'':']+ '"'; 
IDINT : [a-zA-Z]([a-zA-Z0-9]*);       //MyAge
IDSTRING : [a-zA-Z]([a-zA-Z0-9]*)'$';  //MyName$ 
OPERATORMATH : '+'|'-'|'*'|'/';
OPERATORBOOL : '='|'>'|'<'|'>='|'<=';
WS : [ \t\r]+ -> skip;