diff --git a/dust-lang/src/abstract_tree/map_index.rs b/dust-lang/src/abstract_tree/map_index.rs
index ba31f5a..5a08c7e 100644
--- a/dust-lang/src/abstract_tree/map_index.rs
+++ b/dust-lang/src/abstract_tree/map_index.rs
@@ -111,6 +111,8 @@ impl AbstractNode for MapIndex {
         if let (ValueInner::Map(map), Expression::Identifier(identifier)) =
             (collection.inner().as_ref(), &self.right.node)
         {
+            println!("{map:?} {identifier}");
+
             let action = map
                 .get(identifier)
                 .map(|value| Action::Return(value.clone()))
diff --git a/dust-lang/src/context.rs b/dust-lang/src/context.rs
index 56b7a16..24d0726 100644
--- a/dust-lang/src/context.rs
+++ b/dust-lang/src/context.rs
@@ -1,14 +1,39 @@
 use std::{
     collections::BTreeMap,
-    sync::{Arc, RwLock, RwLockReadGuard},
+    sync::{Arc, OnceLock, RwLock, RwLockReadGuard},
 };
 
 use crate::{
     abstract_tree::{Identifier, Type},
+    built_in_functions::BUILT_IN_FUNCTIONS,
     error::{RwLockPoisonError, ValidationError},
-    Value,
+    Interpreter, Value,
 };
 
+static STD_CONTEXT: OnceLock<Context> = OnceLock::new();
+
+pub fn std_context<'a>() -> &'a Context {
+    STD_CONTEXT.get_or_init(|| {
+        let mut data = BTreeMap::new();
+
+        for function in BUILT_IN_FUNCTIONS {
+            data.insert(
+                Identifier::new(function.name()),
+                ValueData::Value(function.as_value()),
+            );
+        }
+
+        let context = Context::with_data(data);
+        let mut interpreter = Interpreter::new(context.clone());
+
+        interpreter.run(include_str!("../../std/io.ds")).unwrap();
+
+        context.remove(&Identifier::new("write_line")).unwrap();
+
+        context
+    })
+}
+
 #[derive(Clone, Debug)]
 pub struct Context {
     inner: Arc<RwLock<BTreeMap<Identifier, ValueData>>>,
@@ -99,6 +124,12 @@ impl Context {
 
         Ok(())
     }
+
+    pub fn remove(&self, identifier: &Identifier) -> Result<Option<ValueData>, RwLockPoisonError> {
+        let removed = self.inner.write()?.remove(identifier);
+
+        Ok(removed)
+    }
 }
 
 #[derive(Clone, Debug, PartialEq)]
diff --git a/dust-lang/src/lib.rs b/dust-lang/src/lib.rs
index e67d8ac..5e4f197 100644
--- a/dust-lang/src/lib.rs
+++ b/dust-lang/src/lib.rs
@@ -6,26 +6,15 @@ pub mod lexer;
 pub mod parser;
 pub mod value;
 
-use abstract_tree::Identifier;
-use built_in_functions::BUILT_IN_FUNCTIONS;
-use context::Context;
+use context::{std_context, Context};
 use error::Error;
 use lexer::lex;
 use parser::parse;
 pub use value::Value;
 
 pub fn interpret(source: &str) -> Result<Option<Value>, Vec<Error>> {
-    let context = Context::new();
+    let mut interpreter = Interpreter::new(std_context().clone());
 
-    for function in BUILT_IN_FUNCTIONS {
-        context
-            .set_value(Identifier::new(function.name()), function.as_value())
-            .unwrap();
-    }
-
-    let mut interpreter = Interpreter::new(context);
-
-    interpreter.run(include_str!("../../std/io.ds"))?;
     interpreter.run(source)
 }