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-# Grammar for Chapter 6
-
-English | [日本語](06-grammar.ja.md)
-
-```antlrv4
-grammar SimpleLanguage;
-
-program
-    : statement+ EOF
-    ;
-
-statement
-    : returnStatement
-    | declStatement
-    | blockStatment
-    | expressionStatement
-    | ifStatement
-    ;
-
-ifStatement
-    : 'if' '(' expression ')' statement ('else' statement)?
-    ;
-
-
-expressionStatement
-    : IDENTIFIER '=' expression ';'
-    ;
-
-blockStatement
-    : '{' statement+ '}'
-    ;
-
-declStatement
-    : 'int' IDENTIFIER '=' expression ';'
-    ;
-
-returnStatement
-    : 'return' expression ';'
-    ;
-
-expression
-    : comparisonExpression
-    ;
-
-comparisonExpression
-    : additiveExpression (('==' | '!='| '>'| '<'| '>='| '<=') additiveExpression)*
-    ;
-
-additiveExpression
-    : multiplicativeExpression (('+' | '-') multiplicativeExpression)*
-    ;
-
-multiplicativeExpression
-    : unaryExpression (('*' | '/') unaryExpression)*
-    ;
-
-unaryExpression
-    : ('-') unaryExpression
-    | primaryExpression
-    ;
-
-primaryExpression
-    : IDENTIFIER
-    | INTEGER_LITERAL
-    | 'true'
-    | 'false'
-    | '(' expression ')'
-    ;
-
-INTEGER_LITERAL
-    : [1-9][0-9]*
-    | [0]
-    ;
-
-IDENTIFIER
-    : NON_DIGIT (NON_DIGIT | DIGIT)*
-    ;
-
-NON_DIGIT: [a-zA-Z_];
-DEC_DIGIT: [0-9];
-```