From 899ecea236288b5ebc7795c204fdad59b3276002 Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Wed, 18 Nov 2020 23:30:46 -0800
Subject: Chapter 8: Add variable declarations

---
 src/com/craftinginterpreters/lox/Parser.java | 30 +++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

(limited to 'src/com/craftinginterpreters/lox/Parser.java')

diff --git a/src/com/craftinginterpreters/lox/Parser.java b/src/com/craftinginterpreters/lox/Parser.java
index c68316f..9a9c0e6 100644
--- a/src/com/craftinginterpreters/lox/Parser.java
+++ b/src/com/craftinginterpreters/lox/Parser.java
@@ -20,7 +20,7 @@ class Parser {
         List<Stmt> statements = new ArrayList<>();
 
         while (!isAtEnd()) {
-            statements.add(statement());
+            statements.add(declaration());
         }
 
         return statements;
@@ -30,6 +30,18 @@ class Parser {
         return equality();
     }
 
+    private Stmt declaration() {
+        try {
+            if (match(VAR))
+                return varDeclaration();
+
+            return statement();
+        } catch (ParseError error) {
+            synchronize();
+            return null;
+        }
+    }
+
     private Stmt statement() {
         if (match(PRINT))
             return printStatement();
@@ -43,6 +55,18 @@ class Parser {
         return new Stmt.Print(value);
     }
 
+    private Stmt varDeclaration() {
+        Token name = consume(IDENTIFIER, "Expect variable name.");
+
+        Expr initializer = null;
+        if (match(EQUAL)) {
+            initializer = expression();
+        }
+
+        consume(SEMICOLON, "Expect ';' after variable declaration.");
+        return new Stmt.Var(name, initializer);
+    }
+
     private Stmt expressionStatement() {
         Expr expr = expression();
         consume(SEMICOLON, "Expect ';' after expression.");
@@ -119,6 +143,10 @@ class Parser {
             return new Expr.Literal(previous().literal);
         }
 
+        if (match(IDENTIFIER)) {
+            return new Expr.Variable(previous());
+        }
+
         if (match(LEFT_PAREN)) {
             Expr expr = expression();
             consume(RIGHT_PAREN, "Expect ')' after expression.");
-- 
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