diff --git a/README.md b/README.md
index 28c1e06..d6be399 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ You can create a multi-statement expression using either `()` syntax or the `~`
 )
 ```
 
-### Global Scope (unimplemented)
+### Global Scope
 
 You can introduce a variable to global scope using the `export` builtin function.
 
diff --git a/src/executor.rs b/src/executor.rs
index 7d13b2c..034f3a7 100644
--- a/src/executor.rs
+++ b/src/executor.rs
@@ -49,7 +49,7 @@ where
     I: Iterator<Item = Result<ParseTree, ParseError>>
 {
     exprs: &'a mut I,
-    globals: HashMap<String, Object>,
+    globals: &'a mut HashMap<String, Object>,
     locals: HashMap<String, Object>,
 }
 
@@ -57,20 +57,15 @@ impl<'a, I> Executor<'a, I>
 where
     I: Iterator<Item = Result<ParseTree, ParseError>>,
 {
-    pub fn new(exprs: &'a mut I) -> Self {
+    pub fn new(exprs: &'a mut I, globals: &'a mut HashMap<String, Object>) -> Self {
         Self {
             exprs,
-            globals: HashMap::new(),
+            globals,
             locals: HashMap::new(),
         }
     }
 
-    pub fn globals(mut self, globals: HashMap<String, Object>) -> Self {
-        self.globals = globals;
-        self
-    }
-
-    pub fn _add_global(mut self, k: String, v: Object) -> Self {
+    pub fn _add_global(self, k: String, v: Object) -> Self {
         self.globals.insert(k, v);
         self
     }
@@ -237,11 +232,11 @@ where
                     Err(RuntimeError::ImmutableError(ident.clone()))
                 } else {
                     let value = self.exec(body)?;
+                    let g = self.globals.clone();
 
-                    Executor::new(self.exprs)
-                        .globals(self.globals.clone())
+                    Executor::new(self.exprs, &mut self.globals)
                         .locals(self.locals.clone())
-                        .add_local(ident, Object::value(value, self.globals.to_owned(), self.locals.to_owned()))
+                        .add_local(ident, Object::value(value, g, self.locals.to_owned()))
                         .exec(scope)
                 }
             },
@@ -249,18 +244,18 @@ where
                 if self.variable_exists(&ident) {
                     Err(RuntimeError::ImmutableError(ident.clone()))
                 } else {
-                    Executor::new(self.exprs)
-                        .globals(self.globals.clone())
+                    let g = self.globals.clone();
+                    Executor::new(self.exprs, &mut self.globals)
                         .locals(self.locals.clone())
-                        .add_local(ident, Object::variable(*body, self.globals.to_owned(), self.locals.to_owned()))
+                        .add_local(ident, Object::variable(*body, g, self.locals.to_owned()))
                         .exec(scope)
                 }
             },
             ParseTree::FunctionDefinition(func, scope) => {
-                Executor::new(self.exprs)
-                    .globals(self.globals.clone())
+                let g = self.globals.clone();
+                Executor::new(self.exprs, &mut self.globals)
                     .locals(self.locals.clone())
-                    .add_local(func.name().unwrap().to_string(), Object::function(func, self.globals.clone(), self.locals.clone()))
+                    .add_local(func.name().unwrap().to_string(), Object::function(func, g, self.locals.clone()))
                     .exec(scope)
             },
             ParseTree::Compose(x, y) => {
@@ -376,6 +371,14 @@ where
                 t => Err(RuntimeError::NoOverloadForTypes("fini".into(), vec![t]))
             },
             ParseTree::Nop => Ok(Value::Nil),
+            ParseTree::Export(names) => {
+                for name in names {
+                    let obj = self.locals.remove(&name).ok_or(RuntimeError::VariableUndefined(name.clone()))?;
+                    self.globals.insert(name, obj);
+                }
+
+                Ok(Value::Nil)
+            }
         }
     }
 }
diff --git a/src/function.rs b/src/function.rs
index 0072636..53fa101 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -50,22 +50,22 @@ impl Function {
 	}
 
 	pub(crate) fn call(&mut self,
-                globals: HashMap<String, Object>,
+                mut globals: HashMap<String, Object>,
                 locals: HashMap<String, Object>,
                 args: Vec<Object>) -> Result<Value, RuntimeError>
     {
         let mut tree = vec![Ok(*self.body.clone())].into_iter();
+        let g = globals.clone();
 
-        let mut exec = Executor::new(&mut tree)
-            .locals(locals.clone())
-            .globals(globals.clone());
+        let mut exec = Executor::new(&mut tree, &mut globals)
+            .locals(locals.clone());
 
         for (obj, name) in std::iter::zip(args.into_iter(), self.arg_names.clone().into_iter()) {
             exec = exec.add_local(name.clone(), obj);
         }
 
         if let Some(name) = self.name().map(|x| x.to_string()) {
-            exec = exec.add_local(name, Object::function(self.clone(), globals, locals));
+            exec = exec.add_local(name, Object::function(self.clone(), g, locals));
         }
 
         exec.next().unwrap()
diff --git a/src/lib.rs b/src/lib.rs
index 31cca04..49cfbf8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -13,7 +13,6 @@ use std::fmt::Display;
 use std::io::BufRead;
 use std::fmt;
 use std::iter::Peekable;
-use std::marker::PhantomData;
 
 #[derive(Clone, Debug)]
 pub enum Type {
@@ -139,9 +138,8 @@ impl Object {
             Cache::Uncached(tree) => {
                 let mut tree = vec![Ok(tree)].into_iter();
 
-                let mut exec = Executor::new(&mut tree)
-                    .locals(self.locals.clone())
-                    .globals(self.globals.clone());
+                let mut exec = Executor::new(&mut tree, &mut self.globals)
+                    .locals(self.locals.clone());
 
                 let v = exec.next().unwrap()?;
 
@@ -163,21 +161,23 @@ impl Object {
 
 pub struct Runtime<'a, R: BufRead> {
     tokenizer: Peekable<Tokenizer<R>>,
+    global_types: HashMap<String, Type>,
+    globals: HashMap<String, Object>,
     parser: Option<Parser<'a, Tokenizer<R>>>,
-    phantom: PhantomData<Executor<'a, Parser<'a, Tokenizer<R>>>>,
 }
 
 impl<'a, R: BufRead> Runtime<'a, R> {
     pub fn new(reader: R) -> Self {
         Self {
             tokenizer: Tokenizer::new(reader).peekable(),
+            global_types: HashMap::new(),
+            globals: HashMap::new(),
             parser: None,
-            phantom: PhantomData,
         }
     }
 
     pub fn values(&'a mut self) -> impl Iterator<Item = Result<Value, RuntimeError>> + 'a {
-        self.parser = Some(Parser::new(&mut self.tokenizer));
-        Executor::new(self.parser.as_mut().unwrap())
+        self.parser = Some(Parser::new(&mut self.tokenizer, &mut self.global_types));
+        Executor::new(self.parser.as_mut().unwrap(), &mut self.globals)
     }
 }
diff --git a/src/parser.rs b/src/parser.rs
index 184a3e3..9973bcb 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1,7 +1,10 @@
 
+use crate::executor::Executor;
+
 use super::{Value, Type, Function, FunctionType};
 use super::tokenizer::{Token, TokenizeError, Op};
 
+use std::borrow::{BorrowMut, Cow};
 use std::error;
 use std::collections::HashMap;
 use std::fmt::Display;
@@ -90,31 +93,32 @@ pub(crate) enum ParseTree {
     // Misc
     Print(Box<ParseTree>),
     Nop,
+    Export(Vec<String>),
 }
 
 /// Parses input tokens and produces ParseTrees for an Executor
 pub(crate) struct Parser<'a, I: Iterator<Item = Result<Token, TokenizeError>>> {
     tokens: &'a mut Peekable<I>,
-    globals: HashMap<String, Type>,
+    globals: &'a mut HashMap<String, Type>,
     locals: HashMap<String, Type>,
 }
 
 impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
-    pub fn new(tokens: &'a mut Peekable<I>) -> Self {
+    pub fn new(tokens: &'a mut Peekable<I>, globals: &'a mut HashMap<String, Type>) -> Self {
         Self {
             tokens: tokens,
-            globals: HashMap::new(),
+            globals,
             locals: HashMap::new()
         }
     }
 
-    pub fn globals(mut self, globals: HashMap<String, Type>) -> Self {
-        self.globals = globals;
+    pub fn add_global(self, k: String, v: Type) -> Self {
+        self.globals.insert(k, v);
         self
     }
 
-    pub fn _add_global(mut self, k: String, v: Type) -> Self {
-        self.globals.insert(k, v);
+    pub fn add_globals<Items: Iterator<Item = (String, Type)>>(self, items: Items) -> Self {
+        items.for_each(|(name, t)| _ = self.globals.insert(name, t));
         self
     }
 
@@ -128,11 +132,20 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
         self
     }
 
+    pub fn add_locals<Items: Iterator<Item = (String, Type)>>(mut self, items: Items) -> Self {
+        items.for_each(|(name, t)| _ = self.locals.insert(name, t));
+        self
+    }
+
     fn get_object_type(&self, ident: &String) -> Result<&Type, ParseError> {
         self.locals.get(ident).or(self.globals.get(ident))
             .ok_or(ParseError::IdentifierUndefined(ident.clone()))
     }
 
+    fn get_object_types<Names: Iterator<Item = String>>(&self, items: Names) -> impl Iterator<Item = Result<&Type, ParseError>> {
+        items.map(|x| self.get_object_type(&x))
+    }
+
     fn parse(&mut self) -> Result<ParseTree, ParseError> {
         match self.tokens.next().ok_or(ParseError::NoInput)?.map_err(|e| ParseError::TokenizeError(e))? {
             Token::Constant(c) => Ok(ParseTree::Constant(c)),
@@ -165,18 +178,16 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
                         if let Token::Identifier(ident) = token {
                             match op {
                                 Op::Equ => Ok(ParseTree::Equ(ident.clone(),
-                                    body.clone(),
-                                    Box::new(Parser::new(self.tokens.by_ref())
+                                    body,
+                                    Box::new(Parser::new(self.tokens.by_ref(), self.globals.borrow_mut())
                                         .locals(self.locals.clone())
-                                        .globals(self.globals.clone())
                                         .add_local(ident, Type::Any)
                                         .parse()?))
                                 ),
                                 Op::LazyEqu => Ok(ParseTree::LazyEqu(ident.clone(),
-                                    body.clone(),
-                                    Box::new(Parser::new(self.tokens.by_ref())
+                                    body,
+                                    Box::new(Parser::new(self.tokens.by_ref(), self.globals.borrow_mut())
                                         .locals(self.locals.clone())
-                                        .globals(self.globals.clone())
                                         .add_local(ident, Type::Any)
                                         .parse()?))
                                 ),
@@ -191,8 +202,7 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
 
                         Ok(ParseTree::FunctionDefinition(f.clone(),
                             Box::new(
-                                Parser::new(self.tokens)
-                                .globals(self.globals.clone())
+                                Parser::new(self.tokens, self.globals.borrow_mut())
                                 .locals(self.locals.clone())
                                 .add_local(f.name().unwrap().to_string(), Type::Function(f.get_type()))
                                 .parse()?
@@ -237,8 +247,7 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
                             .into_iter()
                             .peekable();
 
-                        let trees: Vec<ParseTree> = Parser::new(&mut array_tokens)
-                            .globals(self.globals.to_owned())
+                        let trees: Vec<ParseTree> = Parser::new(&mut array_tokens, self.globals.borrow_mut())
                             .locals(self.locals.to_owned())
                             .collect::<Result<_, ParseError>>()?;
 
@@ -273,8 +282,7 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
                             .into_iter()
                             .peekable();
 
-                        let trees: Vec<ParseTree> = Parser::new(&mut tokens)
-                            .globals(self.globals.to_owned())
+                        let trees: Vec<ParseTree> = Parser::new(&mut tokens, self.globals.borrow_mut())
                             .locals(self.locals.to_owned())
                             .collect::<Result<_, ParseError>>()?;
 
@@ -302,6 +310,27 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
                     Op::Tail => Ok(ParseTree::Tail(Box::new(self.parse()?))),
                     Op::Init => Ok(ParseTree::Init(Box::new(self.parse()?))),
                     Op::Fini => Ok(ParseTree::Fini(Box::new(self.parse()?))),
+                    Op::Export => {
+                        let list = self.parse()?;
+                        let mut g = HashMap::new();
+                        let list = Executor::new(&mut vec![Ok(list)].into_iter(), &mut g).next().unwrap().map_err(|_| ParseError::NoInput)?;
+
+                        if let Value::Array(Type::String, items) = list {
+                            let names = items.into_iter().map(|x| match x {
+                                Value::String(s) => s,
+                                _ => unreachable!(),
+                            });
+
+                            for name in names.clone() {
+                                let t = self.locals.remove(&name).ok_or(ParseError::IdentifierUndefined(name.clone()))?;
+                                self.globals.insert(name, t);
+                            }
+
+                            Ok(ParseTree::Export(names.collect()))
+                        } else {
+                            Err(ParseError::NoInput)
+                        }
+                    }
                     op => Err(ParseError::UnwantedToken(Token::Operator(op))),
                 }
             }
@@ -319,8 +348,7 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
         }
 
         Ok(Function::lambda(t, args, Box::new(
-            Parser::new(self.tokens)
-                .globals(self.globals.clone())
+            Parser::new(self.tokens, &mut self.globals)
                 .locals(locals).parse()?)))
     }
 
@@ -337,8 +365,7 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
         locals.insert(name.clone(), Type::Function(t.clone()));
 
         Ok(Function::named(&name, t, args, Box::new(
-            Parser::new(self.tokens)
-                .globals(self.globals.clone())
+            Parser::new(self.tokens, &mut self.globals)
                 .locals(locals).parse()?)))
     }
 
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index 410343b..b116b42 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -84,6 +84,7 @@ pub enum Op {
     Tail,
     Init,
     Fini,
+    Export,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -128,6 +129,7 @@ impl Token {
             "tail" => Ok(Token::Operator(Op::Tail)),
             "init" => Ok(Token::Operator(Op::Init)),
             "fini" => Ok(Token::Operator(Op::Fini)),
+            "export" => Ok(Token::Operator(Op::Export)),
 
             // Types
             "Any" => Ok(Token::Type(Type::Any)),
@@ -412,4 +414,20 @@ impl<R: BufRead> std::iter::Iterator for Tokenizer<R> {
             Err(e) => Some(Err(TokenizeError::IO(e))),
         }
     }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::str::FromStr;
+
+    use super::*;
+
+    #[test]
+    fn a() {
+        let program = ":. map : f .? x [Any] -> [Any]";
+
+        let tokens: Vec<Token> = Tokenizer::from_str(program).unwrap().collect::<Result<_, _>>().unwrap();
+
+        println!("{tokens:?}");
+    }
 }
\ No newline at end of file