diff --git a/src/ast/builder.rs b/src/ast/builder.rs
index e69de29..e7dc476 100644
--- a/src/ast/builder.rs
+++ b/src/ast/builder.rs
@@ -0,0 +1,80 @@
+use crate::{
+    ast::Statement,
+    diagnostic::{Diagnostic, Error},
+    parser::{grammar::NonTerminal, ParseNode},
+};
+
+use super::Ast;
+
+pub fn build_ast<'a>(parse_tree: &'a ParseNode<'a>) -> Result<Ast<'a>, Vec<Diagnostic<'a>>> {
+    let mut diagnostics = Vec::new();
+    let mut ast = Ast::Statement(Statement::Empty);
+
+    match parse_tree {
+        ParseNode::NonTerminal(NonTerminal::Start, children) => {
+            match children
+                .iter()
+                .map(|child| build_ast(child))
+                .collect::<Result<Vec<_>, _>>()
+            {
+                Ok(_) => {}
+                Err(err) => {
+                    diagnostics.extend(err);
+                }
+            }
+
+            ast = Ast::Statement(Statement::Empty);
+        }
+        _ => {
+            let range = parse_tree.range();
+
+            diagnostics.push(
+                Diagnostic::error("Structure error").with_error(Error::primary(
+                    range.file_id,
+                    range.position,
+                    range.length,
+                    format!("Expected start, got {:?}", parse_tree),
+                )),
+            );
+        }
+    }
+
+    if !diagnostics.is_empty() {
+        Err(diagnostics)
+    } else {
+        Ok(ast)
+    }
+}
+
+pub fn build_top_level_statement<'a>(
+    parse_tree: &'a ParseNode<'a>,
+) -> Result<Ast<'a>, Vec<Diagnostic<'a>>> {
+    match parse_tree {
+        ParseNode::NonTerminal(NonTerminal::RootItems, children) => {
+            let root_items = children
+                .iter()
+                .map(|child| build_ast(child))
+                .collect::<Result<Vec<_>, _>>()?;
+
+            Ok(Ast::Statement(Statement::Empty))
+        }
+        _ => {
+            let range = parse_tree.range();
+
+            return Err(vec![Diagnostic::error("Structure error").with_error(
+                Error::primary(
+                    range.file_id,
+                    range.position,
+                    range.length,
+                    "Expected root items",
+                ),
+            )]);
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn test() {}
+}
diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 5575a85..3d2c128 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -1 +1,23 @@
+use std::collections::HashSet;
+
+use crate::diagnostic::Range;
+
 pub mod builder;
+
+pub enum Ast<'a> {
+    Statement(Statement<'a>),
+}
+pub enum Statement<'a> {
+    Empty,
+    EnumDeclaration(Spanned<'a, EnumDeclaration<'a>>),
+}
+
+pub struct EnumDeclaration<'a> {
+    pub identifier: Spanned<'a, &'a str>,
+    pub items: Vec<Spanned<'a, &'a str>>,
+}
+
+pub struct Spanned<'a, T> {
+    pub value: T,
+    pub range: Range<'a>,
+}
diff --git a/src/main.rs b/src/main.rs
index 70ee375..cf606e7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,5 @@
 use anyhow::Result;
+use ast::builder::build_ast;
 use core::result::Result::Ok;
 use files::Files;
 
@@ -13,7 +14,7 @@ fn main() -> Result<()> {
     files.insert(
         "main",
         "
-        12 + 12;
+        enum colors: green blue red;
     ",
     );
 
@@ -31,10 +32,9 @@ fn main() -> Result<()> {
     };
 
     let parser = parser::EarleyParser::default();
-    let ast = parser.parse(tokens);
 
-    let _ast = match &ast {
-        Ok(ast) => ast,
+    let parse_tree = match parser.parse(tokens) {
+        Ok(parse_tree) => parse_tree,
         Err(diagnostics) => {
             diagnostics
                 .iter()
@@ -43,5 +43,17 @@ fn main() -> Result<()> {
         }
     };
 
+    println!("{:#?}", parse_tree);
+
+    let ast = match build_ast(&parse_tree) {
+        Ok(ast) => ast,
+        Err(diagnostics) => {
+            diagnostics
+                .iter()
+                .for_each(|diagnostic| diagnostic.print(&files));
+            panic!("Failed to build AST");
+        }
+    };
+
     Ok(())
 }
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 2502787..1569376 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -1,7 +1,7 @@
 use grammar::{Grammar, NonTerminal, Term};
 
 use crate::{
-    diagnostic::{Diagnostic, Error},
+    diagnostic::{Diagnostic, Error, Range},
     scanner::token::Token,
 };
 use std::collections::HashSet;
@@ -42,6 +42,24 @@ pub enum ParseNode<'a> {
     NonTerminal(NonTerminal, Vec<ParseNode<'a>>),
 }
 
+impl<'a> ParseNode<'a> {
+    pub fn range(&'a self) -> Range<'a> {
+        match self {
+            ParseNode::Terminal(token) => token.range.clone(),
+            ParseNode::NonTerminal(_, children) => {
+                let start = children.first().unwrap().range().position;
+                let end = children.last().unwrap().range();
+                let end = end.position + end.length;
+                Range {
+                    file_id: children.first().unwrap().range().file_id,
+                    position: start,
+                    length: end - start,
+                }
+            }
+        }
+    }
+}
+
 impl<'a> std::fmt::Display for EarleyItem<'a> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{} -> ", self.head)?;
@@ -267,42 +285,3 @@ impl<'a> EarleyParser<'a> {
         }
     }
 }
-
-#[cfg(test)]
-mod test {
-    use crate::{files::Files, scanner::Scanner};
-
-    #[test]
-    pub fn test() {
-        let mut files = Files::default();
-        files.insert(
-            "main",
-            "
-            enum test: red green blue;
-    ",
-        );
-
-        let scanner = Scanner::new(&files);
-        let tokens = match scanner.parse() {
-            Ok(tokens) => tokens,
-            Err(diagnostics) => {
-                for diagnostic in diagnostics {
-                    diagnostic.print(&files);
-                }
-                panic!("Failed to scan");
-            }
-        };
-
-        let parser = super::EarleyParser::default();
-        match parser.parse(&tokens) {
-            Ok(tree) => {
-                println!("{:#?}", tree);
-            }
-            Err(diagnostics) => {
-                for diagnostic in diagnostics {
-                    diagnostic.print(&files);
-                }
-            }
-        }
-    }
-}