diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 9c77018..c1accf7 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -1,8 +1,8 @@
 use pest::Parser;
 
 pub mod build;
+mod pretty_print;
 pub mod unparse;
-
 // Operators
 
 #[derive(Debug)]
diff --git a/src/ast/pretty_print.rs b/src/ast/pretty_print.rs
new file mode 100644
index 0000000..cdfb5b8
--- /dev/null
+++ b/src/ast/pretty_print.rs
@@ -0,0 +1,231 @@
+use crate::ast::*;
+use crate::util::indent_writer::IndentWriter;
+use std::fmt::Debug;
+
+trait PrettyPrint {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result;
+}
+
+impl PrettyPrint for Identifier {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented(&format!("Identifier({})", self.name))
+    }
+}
+
+impl PrettyPrint for FullyQualifiedName {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("FullyQualifiedName")?;
+        writer.increase_indent();
+        for identifier in &self.0 {
+            identifier.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for TypeUse {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        use TypeUse::*;
+        match self {
+            Void => {
+                writer.writeln_indented("TypeUse(Void)")?;
+            }
+            InterfaceOrClass(t) => {
+                writer.increase_indent();
+                t.pretty_print(writer)?;
+                writer.decrease_indent();
+            }
+            Tuple(t) => {
+                writer.increase_indent();
+                t.pretty_print(writer)?;
+                writer.decrease_indent();
+            }
+            Function(t) => {
+                writer.increase_indent();
+                t.pretty_print(writer)?;
+                writer.decrease_indent();
+            }
+        }
+        Ok(())
+    }
+}
+
+impl PrettyPrint for InterfaceOrClassTypeUse {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented(&format!(
+            "InterfaceOrClassTypeUse(borrow_count = {}, is_mutable = {})",
+            self.borrow_count, self.is_mutable
+        ))?;
+        writer.increase_indent();
+        self.fqn.pretty_print(writer)?;
+        self.generics.pretty_print(writer)?;
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for TupleTypeUse {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented(&format!(
+            "TupleTypeUse(borrow_count = {}, is_mutable = {})",
+            self.borrow_count,
+            self.is_mutable
+        ))?;
+        writer.increase_indent();
+        self.arguments.pretty_print(writer)?;
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for FunctionTypeUse {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented(&format!(
+            "FunctionTypeUse(borrow_count = {})",
+            self.borrow_count
+        ))?;
+        writer.increase_indent();
+        if let Some(function_type_modifier) = &self.function_modifier {
+            function_type_modifier.pretty_print(writer)?;
+        }
+        self.generics.pretty_print(writer)?;
+        self.parameters.pretty_print(writer)?;
+        self.return_type.pretty_print(writer)?;
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for GenericArguments {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("GenericArguments")?;
+        writer.increase_indent();
+        for type_use in &self.0 {
+            type_use.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for GenericParameters {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("GenericParameters")?;
+        writer.increase_indent();
+        for identifier in &self.0 {
+            identifier.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for TupleArguments {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("TupleArguments")?;
+        writer.increase_indent();
+        for type_use in &self.0 {
+            type_use.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for ImplementsList {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("ImplementsList")?;
+        writer.increase_indent();
+        for type_use in &self.0 {
+            type_use.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for FunctionTypeModifier {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        use FunctionTypeModifier::*;
+        writer.writeln_indented(&format!(
+            "FunctionTypeModifier({})",
+            match self {
+                Cons => "cons",
+                MutRef => "mut ref",
+                Mut => "mut",
+                Ref => "ref"
+            }
+        ))
+    }
+}
+
+impl PrettyPrint for Parameters {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("Parameters")?;
+        writer.increase_indent();
+        for parameter in &self.0 {
+            parameter.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for Parameter {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("Parameter")?;
+        writer.increase_indent();
+        self.identifier.pretty_print(writer)?;
+        self.type_use.pretty_print(writer)?;
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for ReturnType {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("ReturnType")?;
+        writer.increase_indent();
+        self.declared_type.pretty_print(writer)?;
+        self.references.pretty_print(writer)?;
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for References {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("References")?;
+        writer.increase_indent();
+        for identifier in &self.0 {
+            identifier.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for CompilationUnit {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        writer.writeln_indented("CompilationUnit")?;
+        writer.increase_indent();
+        if let Some(namespace) = &self.namespace {
+            writer.writeln_indented("Namespace")?;
+            writer.increase_indent();
+            namespace.pretty_print(writer)?;
+            writer.decrease_indent();
+        }
+        for declaration in &self.declarations {
+            declaration.pretty_print(writer)?;
+        }
+        writer.decrease_indent();
+        Ok(())
+    }
+}
+
+impl PrettyPrint for ModuleLevelDeclaration {
+    fn pretty_print(&self, writer: &mut IndentWriter) -> std::fmt::Result {
+        todo!()
+    }    
+}
diff --git a/src/util/indent_writer.rs b/src/util/indent_writer.rs
new file mode 100644
index 0000000..4b62a98
--- /dev/null
+++ b/src/util/indent_writer.rs
@@ -0,0 +1,44 @@
+use std::fmt::Write;
+
+pub struct IndentWriter {
+    indent_level: usize,
+    indent_string: String,
+    out: Box<dyn Write>,
+}
+
+impl IndentWriter {
+    pub fn new(start_level: usize, indent_string: String, out: Box<dyn Write>) -> IndentWriter {
+        IndentWriter {
+            indent_level: start_level,
+            indent_string,
+            out,
+        }
+    }
+
+    pub fn increase_indent(&mut self) {
+        self.indent_level += 1;
+    }
+
+    pub fn decrease_indent(&mut self) {
+        self.indent_level -= 1;
+    }
+
+    pub fn write(&mut self, s: &str) -> std::fmt::Result {
+        write!(self.out, "{}", s)
+    }
+    
+    pub fn writeln(&mut self, s: &str) -> std::fmt::Result {
+        self.write(&format!("{}\n", s))
+    }
+
+    pub fn write_indented(&mut self, s: &str) -> std::fmt::Result {
+        for _ in 0..self.indent_level {
+            write!(self.out, "{}", self.indent_string)?;
+        }
+        write!(self.out, "{}", s)
+    }
+    
+    pub fn writeln_indented(&mut self, s: &str) -> std::fmt::Result {
+        self.write_indented(&format!("{}\n", s))
+    }
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 225296c..5198298 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -1 +1 @@
-pub mod trie;
+pub mod indent_writer;