diff --git a/rust/src/evaluator.rs b/rust/src/evaluator.rs
index 8e670e9..6db0598 100644
--- a/rust/src/evaluator.rs
+++ b/rust/src/evaluator.rs
@@ -1,7 +1,7 @@
 use std::ops;
 use std::collections::HashMap;
 
-use crate::parser;
+use crate::parser::{self, GuardedBlock};
 use parser::Atom;
 
 pub struct Env<'a> {
@@ -42,6 +42,30 @@ pub fn eval(ast: &parser::Stmt, env: &mut Env) {
             println!("{}", eval_expr(expr, env)),
         parser::Stmt::Assignment(id, expr) =>
             env.set(id.clone(), eval_expr(expr, env)),
+        parser::Stmt::Conditional(guarded_blocks, default_block) => {
+            let mut matched = false;
+            for GuardedBlock { guard, block } in guarded_blocks {
+                let res = eval_expr(&guard, env);
+                match res {
+                    Atom::Bool(true) => {
+                        matched = true;
+                        for stmt in block {
+                            eval(stmt, env);
+                        }
+                        break;
+                    }
+                    Atom::Bool(false) => continue,
+                    _ => panic!("Conditional expression does not evaluate to a bool"),
+                }
+            }
+            if !matched {
+                if let Some(block) = default_block {
+                    for expr in default_block {
+                        eval_expr(expr, env);
+                    }
+                }
+            }
+        }
         _ => todo!(),
     }
 }
diff --git a/rust/src/parser.rs b/rust/src/parser.rs
index 2a40e90..5c9173e 100644
--- a/rust/src/parser.rs
+++ b/rust/src/parser.rs
@@ -4,7 +4,7 @@ use std::fmt;
 pub enum Stmt {
     Assignment(String, Expr),
     Funcall(Expr),
-    Conditional(Vec<Expr>, Option<Expr>),
+    Conditional(Vec<GuardedBlock>, Option<Expr>),
     ReplPrint(Expr),
 }
 
@@ -20,7 +20,6 @@ pub enum Expr {
     Mult(Box<Expr>, Box<Expr>),
     Div(Box<Expr>, Box<Expr>),
     Block(Vec<Stmt>),
-    GuardedBlock(Box<GuardedBlock>),
     Object(Vec<Stmt>),
 }
 
@@ -28,6 +27,7 @@ pub enum Expr {
 pub enum Atom {
     String(String),
     Num(f64),
+    Bool(bool),
 }
 
 impl fmt::Display for Atom {
@@ -35,6 +35,7 @@ impl fmt::Display for Atom {
         match self {
             Atom::String(a) => write!(f, "\"{}\"", a),
             Atom::Num(a) => write!(f, "{}", a),
+            Atom::Bool(a) => write!(f, "{}", a),
         }
     }
 }
@@ -68,7 +69,8 @@ peg::parser! {
             f:funcall() { f }
             f:funcdef() { f }
             o:object() { o }
-            i:id() _ { Expr::Id(i) }
+            b:_bool() _ { Expr::Atom(Atom::Bool(b)) }
+            i:id() { Expr::Id(i) }
             n:num() _ { Expr::Atom(Atom::Num(n)) }
 
         }
@@ -79,6 +81,8 @@ peg::parser! {
             = i:id() "<-" _ e:expr() stop() { Stmt::Assignment(i, e) }
         rule num() -> f64
             = n:$(digit()+ "."? digit()* / "." digit()+) _ { n.parse().unwrap() }
+        rule _bool() -> bool
+            = "true" _ { true } / "false" _  { false }
         rule funcall() -> Expr
             = i:id() "(" _ e:(expr() ** ("," _)) ")" _ { Expr::Funcall(i, e) }
         rule funcdef() -> Expr
@@ -88,19 +92,19 @@ peg::parser! {
         rule object() -> Expr
             = "{" _ stop() indent() __* a:assignment()+ dedent() __* "}" _ { Expr::Object(a) }
         
-        rule _if() -> Expr
+        rule _if() -> GuardedBlock
             = "if" _ g:expr() b:indented_block() {
-                Expr::GuardedBlock(Box::new(GuardedBlock {
+                GuardedBlock {
                     guard: g,
                     block: b,
-                }))
+                }
             }
-        rule elif() -> Expr
+        rule elif() -> GuardedBlock
             = "elif" _ g:expr() b:indented_block() {
-                Expr::GuardedBlock(Box::new(GuardedBlock {
+                GuardedBlock {
                     guard: g,
                     block: b
-                }))
+                }
             }
         rule _else() -> Expr
             = "else" _ b:block() { b }