diff --git a/.rustfmt.toml b/.rustfmt.toml
new file mode 100644
index 0000000..4d7dd9e
--- /dev/null
+++ b/.rustfmt.toml
@@ -0,0 +1,3 @@
+imports_granularity = "Crate"
+newline_style = "Unix"
+group_imports = "StdExternalCrate"
\ No newline at end of file
diff --git a/ub_parser/src/ast.rs b/ub_parser/src/ast.rs
index 600116a..1a5d7df 100644
--- a/ub_parser/src/ast.rs
+++ b/ub_parser/src/ast.rs
@@ -1,16 +1,17 @@
-use crate::span::Span;
-use std::path::PathBuf;
+use std::{ops::Range, path::PathBuf};
+
+type Span = Range<usize>;
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct File {
-    name: PathBuf,
-    items: Vec<Item>,
+    pub name: PathBuf,
+    pub items: Vec<Stmt>, // todo make item
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct Ty {
-    span: Span,
-    kind: TyKind,
+    pub span: Span,
+    pub kind: TyKind,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -28,31 +29,31 @@ pub enum Item {
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct FnDecl {
-    name: String,
-    params: Vec<FnParam>,
-    ret_ty: Ty,
-    span: Span,
-    body: Vec<Stmt>,
+    pub name: String,
+    pub params: Vec<FnParam>,
+    pub ret_ty: Ty,
+    pub span: Span,
+    pub body: Vec<Stmt>,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct FnParam {
-    name: String,
-    ty: Ty,
-    span: Span,
+    pub name: String,
+    pub ty: Ty,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct StructDecl {
-    name: String,
-    span: Span,
-    fields: Vec<StructField>,
+    pub name: String,
+    pub span: Span,
+    pub fields: Vec<StructField>,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct StructField {
-    name: String,
-    ty: Ty,
+    pub name: String,
+    pub ty: Ty,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -68,25 +69,25 @@ pub enum Stmt {
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct VarDecl {
-    name: String,
-    ty: Ty,
-    rhs: Option<Expr>,
-    span: Span,
+    pub name: String,
+    pub ty: Ty,
+    pub rhs: Option<Expr>,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct Assignment {
-    place: Place,
-    rhs: Expr,
-    span: Span,
+    pub place: Expr,
+    pub rhs: Expr,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct IfStmt {
-    cond: Expr,
-    body: Vec<Stmt>,
-    else_part: Option<ElsePart>,
-    span: Span,
+    pub cond: Expr,
+    pub body: Vec<Stmt>,
+    pub else_part: Option<ElsePart>,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -97,35 +98,44 @@ pub enum ElsePart {
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct WhileStmt {
-    cond: Expr,
-    body: Vec<Stmt>,
-    span: Span,
+    pub cond: Expr,
+    pub body: Vec<Stmt>,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct LoopStmt {
-    body: Vec<Stmt>,
-    span: Span,
+    pub body: Vec<Stmt>,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub enum Expr {
     BinOp(BinOp),
-    Place(Place),
+    FieldAccess(FieldAccess),
     Call(Call),
     Deref(Box<Expr>),
+    Literal(Literal),
+    Name(String),
+    Array(Vec<Expr>),
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct BinOp {
-    kind: BinOpKind,
-    lhs: Box<Expr>,
-    rhs: Box<Expr>,
-    span: Span,
+    pub kind: BinOpKind,
+    pub lhs: Box<Expr>,
+    pub rhs: Box<Expr>,
+    pub span: Span,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub enum BinOpKind {
+    Eq,
+    Neq,
+    Gt,
+    Lt,
+    GtEq,
+    LtEq,
     Add,
     Sub,
     Mul,
@@ -140,20 +150,20 @@ pub enum BinOpKind {
     Xor,
 }
 
-#[derive(Debug, Clone, PartialEq)]
-pub enum Place {
-    FieldAccess(FieldAccess),
-    Name(String),
-}
-
 #[derive(Debug, Clone, PartialEq)]
 pub struct FieldAccess {
-    expr: Box<Expr>,
-    field_name: String,
+    pub expr: Box<Expr>,
+    pub field_name: String,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub struct Call {
-    callee: Box<Expr>,
-    args: Vec<Expr>,
+    pub callee: Box<Expr>,
+    pub args: Vec<Expr>,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Literal {
+    String(String, Span),
+    Integer(u64, Span),
 }
diff --git a/ub_parser/src/lexer.rs b/ub_parser/src/lexer.rs
index fa4b887..0d9a09d 100644
--- a/ub_parser/src/lexer.rs
+++ b/ub_parser/src/lexer.rs
@@ -1,6 +1,6 @@
 use logos::Logos;
 
-#[derive(Logos, Debug, PartialEq)]
+#[derive(Logos, Debug, Clone, Hash, PartialEq, Eq)]
 pub enum Token<'a> {
     #[regex("//[^\n]*", logos::skip)]
     Comment,
diff --git a/ub_parser/src/lib.rs b/ub_parser/src/lib.rs
index 3bd7707..f70fdae 100644
--- a/ub_parser/src/lib.rs
+++ b/ub_parser/src/lib.rs
@@ -5,7 +5,7 @@ use std::path::PathBuf;
 
 mod ast;
 mod lexer;
-mod span;
+mod parser;
 
 pub fn parse(_str: &str, _file_name: PathBuf) -> Result<ast::File, ()> {
     todo!()
diff --git a/ub_parser/src/parser.rs b/ub_parser/src/parser.rs
new file mode 100644
index 0000000..a07be8d
--- /dev/null
+++ b/ub_parser/src/parser.rs
@@ -0,0 +1,168 @@
+use std::{ops::Range, path::PathBuf};
+
+use chumsky::{prelude::*, Stream};
+
+use crate::{
+    ast::{BinOp, BinOpKind, Call, Expr, File, Literal, Stmt},
+    lexer::Token,
+};
+
+type Error<'src> = Simple<Token<'src>>;
+type Span = Range<usize>;
+
+fn ident_parser<'src>() -> impl Parser<Token<'src>, &'src str, Error = Error<'src>> + Clone {
+    filter_map(|span, tok| match tok {
+        Token::Ident(ident) => Ok(ident),
+        _ => Err(Simple::expected_input_found(span, Vec::new(), Some(tok))),
+    })
+    .labelled("identifier")
+}
+
+fn expr_parser<'src>() -> impl Parser<Token<'src>, Expr, Error = Error<'src>> + Clone {
+    recursive(|expr| {
+        let literal = filter_map(|span, token| match token {
+            Token::String(str) => Ok(Expr::Literal(Literal::String(
+                str[1..str.len() - 2].to_owned(),
+                span,
+            ))),
+            // todo lol unwrap
+            Token::Integer(int) => Ok(Expr::Literal(Literal::Integer(int.parse().unwrap(), span))),
+            _ => Err(Simple::expected_input_found(span, Vec::new(), Some(token))),
+        })
+        .labelled("literal");
+
+        // A list of expressions
+        let items = expr
+            .clone()
+            .chain(just(Token::Comma).ignore_then(expr.clone()).repeated())
+            .then_ignore(just(Token::Comma).or_not())
+            .or_not()
+            .map(|item| item.unwrap_or_else(Vec::new));
+
+        let array = items
+            .clone()
+            .delimited_by(just(Token::BracketO), just(Token::BracketC))
+            .map(Expr::Array);
+
+        let atom = literal
+            .or(ident_parser().map(|str| Expr::Name(str.to_owned())))
+            .or(array)
+            .or(expr
+                .clone()
+                .delimited_by(just(Token::ParenO), just(Token::ParenC)));
+
+        let call = atom
+            .then(
+                items
+                    .delimited_by(just(Token::ParenO), just(Token::ParenC))
+                    .repeated(),
+            )
+            .foldl(|callee, args| {
+                Expr::Call(Call {
+                    callee: Box::new(callee),
+                    args,
+                })
+            });
+
+        let op = just(Token::Asterisk)
+            .to(BinOpKind::Mul)
+            .or(just(Token::Slash).to(BinOpKind::Div));
+
+        let product = call
+            .clone()
+            .then(op.then(call).repeated())
+            .foldl(|a, (kind, b)| {
+                Expr::BinOp(BinOp {
+                    kind,
+                    lhs: Box::new(a),
+                    rhs: Box::new(b),
+                    span: 0..0, // lol todo
+                })
+            });
+
+        // Sum ops (add and subtract) have equal precedence
+        let op = just(Token::Plus)
+            .to(BinOpKind::Add)
+            .or(just(Token::Minus).to(BinOpKind::Sub));
+        let sum = product
+            .clone()
+            .then(op.then(product).repeated())
+            .foldl(|a, (kind, b)| {
+                Expr::BinOp(BinOp {
+                    kind,
+                    lhs: Box::new(a),
+                    rhs: Box::new(b),
+                    span: 0..0, // lol todo
+                })
+            });
+
+        // Comparison ops (equal, not-equal) have equal precedence
+        let op = just(Token::EqEq)
+            .to(BinOpKind::Eq)
+            .or(just(Token::BangEq).to(BinOpKind::Neq));
+        let compare = sum
+            .clone()
+            .then(op.then(sum).repeated())
+            .foldl(|a, (kind, b)| {
+                Expr::BinOp(BinOp {
+                    kind,
+                    lhs: Box::new(a),
+                    rhs: Box::new(b),
+                    span: 0..0, // lol todo
+                })
+            });
+
+        compare
+    })
+}
+
+fn file_parser<'src>(
+    file_name: PathBuf,
+) -> impl Parser<Token<'src>, File, Error = Error<'src>> + Clone {
+    expr_parser()
+        .map(move |expr| File {
+            name: file_name.clone(),
+            items: vec![Stmt::Expr(expr)],
+        })
+        .then_ignore(just(Token::Semi))
+}
+
+pub fn parse<'src, I>(lexer: I, len: usize, file_name: PathBuf) -> (Option<File>, Vec<Error<'src>>)
+where
+    I: 'src,
+    I: Iterator<Item = (Token<'src>, Span)>,
+{
+    file_parser(file_name).parse_recovery(Stream::from_iter(len..len + 1, lexer))
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{fmt::Debug, path::PathBuf};
+
+    use logos::Logos;
+
+    use crate::lexer::Token;
+
+    fn parse(src: &str) -> impl Debug + '_ {
+        let lexer = Token::lexer(src);
+        let len = lexer.source().len();
+
+        super::parse(
+            lexer.spanned(),
+            len,
+            PathBuf::from(module_path!().replace("::", "__")),
+        )
+    }
+
+    #[test]
+    fn addition() {
+        let r = parse("1 + 4;");
+        insta::assert_debug_snapshot!(r);
+    }
+
+    #[test]
+    fn expression() {
+        let r = parse("(4 / hallo()) + 5;");
+        insta::assert_debug_snapshot!(r)
+    }
+}
diff --git a/ub_parser/src/snapshots/ub_parser__parser__tests__addition.snap b/ub_parser/src/snapshots/ub_parser__parser__tests__addition.snap
new file mode 100644
index 0000000..45cec1d
--- /dev/null
+++ b/ub_parser/src/snapshots/ub_parser__parser__tests__addition.snap
@@ -0,0 +1,34 @@
+---
+source: ub_parser/src/parser.rs
+expression: r
+---
+(
+    Some(
+        File {
+            name: "ub_parser__parser__tests",
+            items: [
+                Expr(
+                    BinOp(
+                        BinOp {
+                            kind: Add,
+                            lhs: Literal(
+                                Integer(
+                                    1,
+                                    0..1,
+                                ),
+                            ),
+                            rhs: Literal(
+                                Integer(
+                                    4,
+                                    4..5,
+                                ),
+                            ),
+                            span: 0..0,
+                        },
+                    ),
+                ),
+            ],
+        },
+    ),
+    [],
+)
diff --git a/ub_parser/src/snapshots/ub_parser__parser__tests__expression.snap b/ub_parser/src/snapshots/ub_parser__parser__tests__expression.snap
new file mode 100644
index 0000000..29c45e2
--- /dev/null
+++ b/ub_parser/src/snapshots/ub_parser__parser__tests__expression.snap
@@ -0,0 +1,48 @@
+---
+source: ub_parser/src/parser.rs
+expression: r
+---
+(
+    Some(
+        File {
+            name: "ub_parser__parser__tests",
+            items: [
+                Expr(
+                    BinOp(
+                        BinOp {
+                            kind: Add,
+                            lhs: BinOp(
+                                BinOp {
+                                    kind: Div,
+                                    lhs: Literal(
+                                        Integer(
+                                            4,
+                                            1..2,
+                                        ),
+                                    ),
+                                    rhs: Call(
+                                        Call {
+                                            callee: Name(
+                                                "hallo",
+                                            ),
+                                            args: [],
+                                        },
+                                    ),
+                                    span: 0..0,
+                                },
+                            ),
+                            rhs: Literal(
+                                Integer(
+                                    5,
+                                    16..17,
+                                ),
+                            ),
+                            span: 0..0,
+                        },
+                    ),
+                ),
+            ],
+        },
+    ),
+    [],
+)
diff --git a/ub_parser/src/span.rs b/ub_parser/src/span.rs
deleted file mode 100644
index 883bc42..0000000
--- a/ub_parser/src/span.rs
+++ /dev/null
@@ -1,22 +0,0 @@
-use std::ops::Range;
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct Span {
-    start: usize,
-    len: usize,
-}
-
-impl Span {
-    pub fn start_end(start: usize, end: usize) -> Self {
-        Self {
-            start,
-            len: end - start,
-        }
-    }
-}
-
-impl From<Range<usize>> for Span {
-    fn from(r: Range<usize>) -> Self {
-        Self::start_end(r.start, r.end)
-    }
-}