From e4199d2837d2179f17e97b8d50366d96c8babded Mon Sep 17 00:00:00 2001
From: Cody <cody@codyq.dev>
Date: Mon, 27 Feb 2023 12:14:16 -0600
Subject: Added while loops & guessing game

---
 examples/guessing.sloth | 26 ++++++++++++++++++++++++++
 examples/test.sloth     | 16 ----------------
 src/ast/mod.rs          |  4 ++++
 src/ast/parser.rs       | 11 +++++++++++
 src/interpreter.rs      |  5 +++++
 src/lexer.rs            |  2 ++
 6 files changed, 48 insertions(+), 16 deletions(-)
 create mode 100644 examples/guessing.sloth
 delete mode 100644 examples/test.sloth

diff --git a/examples/guessing.sloth b/examples/guessing.sloth
new file mode 100644
index 0000000..5d69944
--- /dev/null
+++ b/examples/guessing.sloth
@@ -0,0 +1,26 @@
+val computer = random(1, 10);
+
+var tries = 0;
+var correct = false;
+
+while !correct {
+    print("\nPick a number between 1 and 5: ");
+    val human = parse_int(readln());
+
+    if human == computer {
+        println("You guessed the same number as me!");
+        correct = true;
+    }
+    
+    if human > computer {
+        println("Your guess was too high.");
+    }
+    
+    if human < computer {
+        println("Your guess was too low.");
+    }
+    
+    tries = tries + 1;
+}
+
+println("\nIt took you ", tries, " tries to guess correctly!");
diff --git a/examples/test.sloth b/examples/test.sloth
deleted file mode 100644
index 7104593..0000000
--- a/examples/test.sloth
+++ /dev/null
@@ -1,16 +0,0 @@
-print("Pick a number between 1 and 5: ");
-
-val human = parse_int(readln());
-val computer = random(1, 5);
-
-if human == computer {
-    println("You guessed the same number as me!");
-}
-
-if human > computer {
-    println("Your guess was too high.");
-}
-
-if human < computer {
-    println("Your guess was too low.");
-}
diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index d006737..4e1d639 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -36,6 +36,10 @@ pub enum Stmt {
         range: (Expr, Expr),
         body: Vec<Stmt>,
     },
+    While {
+        condition: Expr,
+        body: Vec<Stmt>,
+    },
     Return {
         value: Expr,
     },
diff --git a/src/ast/parser.rs b/src/ast/parser.rs
index 842ad09..bc29f94 100644
--- a/src/ast/parser.rs
+++ b/src/ast/parser.rs
@@ -118,6 +118,10 @@ impl<'a> AstParser<'a> {
             return self.for_statement();
         }
 
+        if self.advance_if_eq(&TokenType::While) {
+            return self.while_statement();
+        }
+
         // If we couldn't parse a statement return an expression statement
         self.expression_statement()
     }
@@ -186,6 +190,13 @@ impl<'a> AstParser<'a> {
         }
     }
 
+    fn while_statement(&mut self) -> Stmt {
+        let condition = self.expression();
+        let body = self.block();
+
+        Stmt::While { condition, body }
+    }
+
     fn expression_statement(&mut self) -> Stmt {
         let expr = self.expression();
 
diff --git a/src/interpreter.rs b/src/interpreter.rs
index b548d9e..adf6755 100644
--- a/src/interpreter.rs
+++ b/src/interpreter.rs
@@ -69,6 +69,11 @@ impl AstVisitor<Value> for AstInterpreter {
 
                 self.memory.remove(binding);
             }
+            Stmt::While { condition, body } => {
+                while self.visit_expr(condition) == Value::Bool(true) {
+                    self.interpret(body);
+                }
+            }
             Stmt::Return { value } => todo!(),
         };
 
diff --git a/src/lexer.rs b/src/lexer.rs
index 2d65afc..01d1ab6 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -283,6 +283,8 @@ impl<'a> Iterator for Lexer<'a> {
                     "loop" => TokenType::Loop,
                     "break" => TokenType::Break,
                     "continue" => TokenType::Continue,
+                    "true" => TokenType::Literal(Literal::Bool(true)),
+                    "false" => TokenType::Literal(Literal::Bool(false)),
                     _ => TokenType::Identifier(value),
                 }
             }
-- 
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