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+# 第1章の文法
+
+[English](01-grammar.md) | 日本語
+
+この文書は [第1章の文法定義](01-grammar.md) の日本語版です。文法定義そのものは原文と同一です。
+
+[第1章：導入に戻る](../README.ja.md)
+
+```antlrv4
+grammar SimpleLanguage;
+
+program
+    : statement EOF
+    ;
+
+statement
+    : 'return' expression ';'
+    ;
+
+expression
+    : primaryExpression
+    ;
+
+primaryExpression
+    : INTEGER_LITERAL
+    ;
+
+INTEGER_LITERAL
+    : [1-9][0-9]*
+    | [0]
+    ;
+```
diff --git a/chapter01/docs/01-grammar.md b/chapter01/docs/01-grammar.md
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@@ -1,5 +1,7 @@
 # Grammar for Chapter 1
 
+English | [日本語](01-grammar.ja.md)
+
 ```antlrv4
 grammar SimpleLanguage;