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+# 第9章の文法
+
+[English](09-grammar.md) | 日本語
+
+この文書は [原文](09-grammar.md) の日本語訳です。
+
+> 訳注: 原文の見出しは「Grammar for Chapter 8」ですが、このファイルは第9章に属するため、訳の見出しは第9章としています。文法は原文のまま保持しています。
+
+
+[第9章に戻る](../README.ja.md)
+
+```antlrv4
+grammar SimpleLanguage;
+
+program
+    : statement+ EOF
+    ;
+
+statement
+    : returnStatement
+    | declStatement
+    | blockStatment
+    | expressionStatement
+    | ifStatement
+    | whileStatement
+    | breakStatement
+    | continueStatment
+    ;
+
+whileStatement
+    : 'while' '(' expression ')' statement
+    ;
+
+breakStatement
+    : 'break' ';'
+    ;
+
+continueStatement
+    : 'continue' ';'
+    ;
+
+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];
+```
diff --git a/chapter09/docs/09-grammar.md b/chapter09/docs/09-grammar.md
index 00f93e04..5f6d5209 100644
--- a/chapter09/docs/09-grammar.md
+++ b/chapter09/docs/09-grammar.md
@@ -1,5 +1,7 @@
 # Grammar for Chapter 8
 
+English | [日本語](09-grammar.ja.md)
+
 ```antlrv4
 grammar SimpleLanguage;