Added a grammar definition for chapter 01.

3 files changed, 50 insertions, 1 deletions

diff --git a/README.md b/README.md
index f764099c..78db3c08 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ Sea Of Nodes intermediate representation.
 The simple language will be a small subset of C. 
 
 * [Common](common/README.md): Common utilities including a lexer.
-* [Language](language/README.md): definition.
+* [Language](language/README.md): Simple language definition.
 * [Chapter 1](chapter01/README.md): Simple control flow statements, `if` and `while`. Variables of `int` type. Simple 
   arithmetic such as addition, subtraction, multiplication, division. Non-zero values will be truthy.
 * Chapter 2: Function calls.
diff --git a/chapter01/README.md b/chapter01/README.md
index e69de29b..d21a55e8 100644
--- a/chapter01/README.md
+++ b/chapter01/README.md
@@ -0,0 +1,10 @@
+# Chapter 1
+Simple control flow statements
+
+The chapter will implement:
+* Control flow statements, `if` and `while`. 
+* Variables of `int` type. 
+* Simple arithmetic such as addition, subtraction, multiplication, division. 
+* Non-zero values will be truthy.
+
+* [Grammar](docs/01-grammar.md)
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diff --git a/chapter01/docs/01-grammar.md b/chapter01/docs/01-grammar.md
index e69de29b..92ed7357 100644
--- a/chapter01/docs/01-grammar.md
+++ b/chapter01/docs/01-grammar.md
@@ -0,0 +1,39 @@
+# Grammar for Chapter 1
+
+```antlrv4
+grammar SimpleLanguage;
+
+program
+    : declaration* statement+ EOF
+    ;
+
+declaration
+    : type IDENTIFIER ';'
+    ;
+
+type
+    : 'int'
+    ;
+
+statement
+    : 'if' '(' expression ')' statement
+    | 'if' '(' expression ')' statement 'else' statement
+    | 'while' '(' expression ')' statement
+    | IDENTIFIER '=' expression ';'
+    | '{' declaration* statement+ '}'
+    | 'break' ';'
+    ;
+
+expression
+    : primaryExpression                                             # PrimaryExpression_
+    | expression ('*' | '/' ) expression                            # ArithmeticOrLogicalExpression
+    | expression ('+' | '-') expression                             # ArithmeticOrLogicalExpression
+    ;
+
+primaryExpression
+    :
+    | INTEGER_LITERAL
+    | IDENTIFIER
+    | '(' expression ')'
+    ;
+```
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