diff --git a/Cargo.lock b/Cargo.lock
index 591a1f5..e0a132f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -20,6 +20,7 @@ dependencies = [
  "nucleo-matcher",
  "regex",
  "shlex",
+ "thiserror",
 ]
 
 [[package]]
@@ -698,6 +699,26 @@ version = "0.13.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e502f78cdbb8ba4718f566c418c52bc729126ffd16baee5baa718cf25dd5a69a"
 
+[[package]]
+name = "thiserror"
+version = "2.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "567b8a2dae586314f7be2a752ec7474332959c6460e02bde30d702a66d488708"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f7cf42b4507d8ea322120659672cf1b9dbb93f8f2d4ecfd6e51350ff5b17a1d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "toml"
 version = "0.8.23"
diff --git a/Cargo.toml b/Cargo.toml
index 9c0beee..f0addc4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,3 +9,4 @@ gtk4-layer-shell = "0.5.0"
 nucleo-matcher = "0.3.1"
 regex = "1.11.1"
 shlex = "1.3.0"
+thiserror = "2.0.12"
diff --git a/src/main.rs b/src/main.rs
index 20266db..fffa559 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,4 @@
+pub mod math;
 pub mod modules;
 pub mod widget;
 
diff --git a/src/math/eval.rs b/src/math/eval.rs
new file mode 100644
index 0000000..0c7b45e
--- /dev/null
+++ b/src/math/eval.rs
@@ -0,0 +1,65 @@
+use thiserror::Error;
+
+use crate::math::{BinMathOp, MathExpr, Number, UnMathOp};
+
+pub fn eval_math_expr(expr: MathExpr) -> Result<Number, MathEvalError> {
+    match expr {
+        MathExpr::Number(n) => Ok(n),
+        // TODO: Non floating point arithmetic please
+        MathExpr::Sym("pi") => Ok(std::f64::consts::PI),
+        MathExpr::Sym("e") => Ok(std::f64::consts::E),
+        MathExpr::Sym(s) => Err(MathEvalError::UnkownSymbol(s)),
+        MathExpr::UnOp(UnMathOp::Minus, expr) => Ok(-eval_math_expr(*expr)?),
+        MathExpr::BinOp(BinMathOp::Add, lhs, rhs) => {
+            Ok(eval_math_expr(*lhs)? + eval_math_expr(*rhs)?)
+        }
+        MathExpr::BinOp(BinMathOp::Sub, lhs, rhs) => {
+            Ok(eval_math_expr(*lhs)? - eval_math_expr(*rhs)?)
+        }
+        MathExpr::BinOp(BinMathOp::Mult, lhs, rhs) => {
+            Ok(eval_math_expr(*lhs)? * eval_math_expr(*rhs)?)
+        }
+        MathExpr::BinOp(BinMathOp::Div, lhs, rhs) => {
+            Ok(eval_math_expr(*lhs)? / eval_math_expr(*rhs)?)
+        }
+        MathExpr::BinOp(BinMathOp::Pow, lhs, rhs) => {
+            Ok(eval_math_expr(*lhs)?.powf(eval_math_expr(*rhs)?))
+        }
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum MathEvalError<'a> {
+    #[error("Encountered unkown symbol while evaluating: {0}")]
+    UnkownSymbol(&'a str),
+}
+
+#[cfg(test)]
+mod test {
+    use crate::math::{
+        Number,
+        eval::{MathEvalError, eval_math_expr},
+        parser::parse_expr_from_tokens,
+        tokenizer::tokenize,
+    };
+
+    fn eval_str(input: &str) -> Result<Number, MathEvalError> {
+        eval_math_expr(parse_expr_from_tokens(tokenize(input).unwrap()).unwrap())
+    }
+
+    #[test]
+    fn basic_expressions() {
+        assert_eq!(eval_str("1+1").unwrap(), 2.0);
+        assert_eq!(eval_str("(1+1) * 6").unwrap(), 12.0);
+        assert_eq!(eval_str("1/2").unwrap(), 0.5);
+        assert_eq!(eval_str("2+2*3").unwrap(), 8.0);
+        assert_eq!(eval_str("2+2*3**2").unwrap(), 20.0);
+        assert_eq!(eval_str("pi").unwrap(), std::f64::consts::PI);
+        assert_eq!(eval_str("e").unwrap(), std::f64::consts::E);
+        assert_eq!(eval_str("2*pi").unwrap(), 2.0 * std::f64::consts::PI);
+        assert_eq!(
+            eval_str("pi * e").unwrap(),
+            std::f64::consts::PI * std::f64::consts::E
+        );
+    }
+}
diff --git a/src/math/mod.rs b/src/math/mod.rs
new file mode 100644
index 0000000..3ed1d69
--- /dev/null
+++ b/src/math/mod.rs
@@ -0,0 +1,112 @@
+// TODO: This should be its own crate
+use std::fmt::Display;
+
+pub mod eval;
+pub mod parser;
+pub mod tokenizer;
+
+// TODO: Non floating point arithmetic please
+pub type Number = f64;
+
+#[derive(Debug, PartialEq, PartialOrd, Clone)]
+pub enum MathExpr<'a> {
+    Number(Number),
+    Sym(&'a str),
+    UnOp(UnMathOp, Box<MathExpr<'a>>),
+    BinOp(BinMathOp, Box<MathExpr<'a>>, Box<MathExpr<'a>>),
+}
+
+impl<'a> Display for MathExpr<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MathExpr::Number(n) => write!(f, "{n}"),
+            MathExpr::Sym(s) => write!(f, "{s}"),
+            MathExpr::UnOp(op, expr) => write!(f, "{op}{expr}"),
+            MathExpr::BinOp(op, lhs, rhs) => write!(f, "({lhs}{op}{rhs})"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, PartialOrd, Clone)]
+pub enum UnMathOp {
+    Minus,
+}
+
+impl Display for UnMathOp {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            UnMathOp::Minus => f.write_str("-"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, PartialOrd, Clone)]
+pub enum BinMathOp {
+    Add,
+    Sub,
+    Mult,
+    Div,
+    // TODO: Integer division
+    // IntegerDiv,
+    Pow,
+}
+
+impl Display for BinMathOp {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            BinMathOp::Add => f.write_str("+"),
+            BinMathOp::Sub => f.write_str("-"),
+            BinMathOp::Mult => f.write_str("*"),
+            BinMathOp::Div => f.write_str("/"),
+            BinMathOp::Pow => f.write_str("^"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, PartialOrd, Clone, Copy)]
+pub enum MathToken<'a> {
+    Number(Number),
+    Sym(&'a str),
+    LParen,
+    RParen,
+    Plus,
+    Minus,
+    Slash,
+    Star,
+    DoubleStar,
+    Caret,
+}
+
+impl<'a> Display for MathToken<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MathToken::Number(n) => write!(f, "{n}"),
+            MathToken::Sym(s) => write!(f, "{s}"),
+            MathToken::LParen => f.write_str("("),
+            MathToken::RParen => f.write_str(")"),
+            MathToken::Plus => f.write_str("+"),
+            MathToken::Minus => f.write_str("-"),
+            MathToken::Slash => f.write_str("/"),
+            MathToken::Star => f.write_str("*"),
+            MathToken::DoubleStar => f.write_str("**"),
+            MathToken::Caret => f.write_str("^"),
+        }
+    }
+}
+
+impl<'a> MathToken<'a> {
+    pub fn precedence(&self) -> u8 {
+        match self {
+            MathToken::Number(_) => 0,
+            MathToken::Sym(_) => 0,
+            MathToken::LParen => 0,
+            MathToken::RParen => 0,
+            MathToken::Plus => 1,
+            MathToken::Minus => 1,
+            MathToken::Slash => 2,
+            MathToken::Star => 2,
+            MathToken::DoubleStar => 3,
+            MathToken::Caret => 3,
+        }
+    }
+}
diff --git a/src/math/parser.rs b/src/math/parser.rs
new file mode 100644
index 0000000..14a2104
--- /dev/null
+++ b/src/math/parser.rs
@@ -0,0 +1,210 @@
+use std::iter::Peekable;
+
+use thiserror::Error;
+
+use crate::math::{BinMathOp, MathExpr, MathToken, UnMathOp};
+
+// New thing on stack -> [what to consume, other thing to consume]
+// Done -> BinOp <eof>
+
+// Grammer for LR parser
+// <> is a terminal
+//
+//  <unOp> := '-'
+//  <binOp1> := '+' | '-'
+//  <binOp2> := '/' | '*'
+//  <binOp3> := '**' | '^'
+//  <function> := 'sqrt' | 'sin' | 'cos' | etc
+//
+//
+// F :=
+//  | <number>
+//  | <sym>
+//  | '(' binOp1 ')'
+//  | <unOp> F
+//  | <function> '(' binOp1 ')'
+//
+//
+// binOp3 :=
+//  | binOp3 <binOp3> F
+//  | F
+//
+// binOp2 :=
+//  | binOp2 <binOp2> binOp3
+//  | binOp2 '(' expr ')'  [Implicit multiplication] // TODO:
+//  | binOp3
+//
+// binOp1 :=
+//  | binOp1 <binOp1> binOp2
+//  | binOp2
+//
+// goal := binOp1 <eof>
+
+pub fn parse_expr_from_tokens(tokens: Vec<MathToken>) -> Result<MathExpr, MathParserError> {
+    let mut tokens = tokens.into_iter().peekable();
+    parse_expr(&mut tokens)
+}
+
+fn parse_primary<'a>(
+    tokens: &mut Peekable<impl Iterator<Item = MathToken<'a>>>,
+) -> Result<MathExpr<'a>, MathParserError<'a>> {
+    match tokens.next() {
+        Some(MathToken::Number(n)) => Ok(MathExpr::Number(n)),
+        Some(MathToken::Sym(s)) => Ok(MathExpr::Sym(s)),
+        Some(MathToken::LParen) => {
+            let expr = parse_expr(tokens)?;
+            match tokens.next() {
+                Some(MathToken::RParen) => Ok(expr),
+                Some(t) => Err(MathParserError::UnexpectedToken(t)),
+                None => Err(MathParserError::EndOfExpression),
+            }
+        }
+        Some(MathToken::Minus) => Ok(MathExpr::UnOp(
+            UnMathOp::Minus,
+            Box::new(parse_expr(tokens)?),
+        )),
+        // TODO: Function calls such as sqrt, sin, etc
+        Some(t) => Err(MathParserError::UnexpectedToken(t)),
+        None => Err(MathParserError::EndOfExpression),
+    }
+}
+
+fn parse_expr<'a>(
+    tokens: &mut Peekable<impl Iterator<Item = MathToken<'a>>>,
+) -> Result<MathExpr<'a>, MathParserError<'a>> {
+    parse_expr_prime(parse_primary(tokens)?, tokens, 0)
+}
+
+fn parse_expr_prime<'a>(
+    mut lhs: MathExpr<'a>,
+    tokens: &mut Peekable<impl Iterator<Item = MathToken<'a>>>,
+    min_precedence: u8,
+) -> Result<MathExpr<'a>, MathParserError<'a>> {
+    loop {
+        match tokens.peek() {
+            // If the token has zero precedence it is not an operator and should stop expression
+            // parsing.
+            Some(t) if t.precedence() == 0 => return Ok(lhs),
+            // If the token has a precedence lower then the minimum we don't parse it right now.
+            Some(t) if t.precedence() < min_precedence => return Ok(lhs),
+            // If the token has a precedence of at least min_precedence we parse it.
+            Some(token) => {
+                let op_precedence = token.precedence();
+                let op = parse_bin_op_from_token(*token)?;
+                // Advance iterator
+                let _ = tokens.next();
+                let mut rhs = parse_primary(tokens)?;
+                loop {
+                    match tokens.peek() {
+                        Some(t) if t.precedence() > op_precedence => {
+                            rhs = parse_expr_prime(rhs, tokens, op_precedence + 1)?;
+                        }
+                        _ => break,
+                    }
+                }
+                lhs = MathExpr::BinOp(op, Box::new(lhs), Box::new(rhs));
+            }
+            None => return Ok(lhs),
+        }
+    }
+}
+
+fn parse_bin_op_from_token(token: MathToken) -> Result<BinMathOp, MathParserError> {
+    match token {
+        MathToken::Plus => Ok(BinMathOp::Add),
+        MathToken::Minus => Ok(BinMathOp::Sub),
+        MathToken::Slash => Ok(BinMathOp::Div),
+        MathToken::Star => Ok(BinMathOp::Mult),
+        MathToken::DoubleStar => Ok(BinMathOp::Pow),
+        MathToken::Caret => Ok(BinMathOp::Pow),
+        t => Err(MathParserError::UnexpectedToken(t)),
+    }
+}
+
+#[derive(Debug, Error, PartialEq)]
+pub enum MathParserError<'a> {
+    #[error("Unexpected token {0}")]
+    UnexpectedToken(MathToken<'a>),
+    #[error("Reached the end of the expression")]
+    EndOfExpression,
+}
+
+#[cfg(test)]
+mod test {
+    use crate::math::parser::{MathParserError, parse_expr_from_tokens};
+    use crate::math::tokenizer::tokenize;
+    use crate::math::{BinMathOp, MathExpr, MathToken::*};
+
+    #[test]
+    fn basic_examples() {
+        assert_eq!(
+            parse_expr_from_tokens(vec![]).err().unwrap(),
+            MathParserError::EndOfExpression
+        );
+        assert_eq!(
+            parse_expr_from_tokens(vec![Number(1.)]).unwrap(),
+            MathExpr::Number(1.)
+        );
+        assert_eq!(
+            parse_expr_from_tokens(vec![Number(1.), Plus, Number(1.)]).unwrap(),
+            MathExpr::BinOp(
+                BinMathOp::Add,
+                Box::new(MathExpr::Number(1.)),
+                Box::new(MathExpr::Number(1.))
+            )
+        );
+        assert_eq!(
+            parse_expr_from_tokens(vec![LParen, Number(1.), Plus, Number(1.), RParen]).unwrap(),
+            MathExpr::BinOp(
+                BinMathOp::Add,
+                Box::new(MathExpr::Number(1.)),
+                Box::new(MathExpr::Number(1.))
+            )
+        );
+    }
+
+    #[test]
+    fn advanced_examples() {
+        assert_eq!(
+            parse_expr_from_tokens(tokenize("1+2*3-5**10").unwrap()).unwrap(),
+            MathExpr::BinOp(
+                BinMathOp::Sub,
+                Box::new(MathExpr::BinOp(
+                    BinMathOp::Add,
+                    Box::new(MathExpr::Number(1.)),
+                    Box::new(MathExpr::BinOp(
+                        BinMathOp::Mult,
+                        Box::new(MathExpr::Number(2.)),
+                        Box::new(MathExpr::Number(3.))
+                    ))
+                )),
+                Box::new(MathExpr::BinOp(
+                    BinMathOp::Pow,
+                    Box::new(MathExpr::Number(5.)),
+                    Box::new(MathExpr::Number(10.))
+                ))
+            )
+        );
+
+        assert_eq!(
+            parse_expr_from_tokens(tokenize("(1+(2*3))-(5**10)").unwrap()).unwrap(),
+            MathExpr::BinOp(
+                BinMathOp::Sub,
+                Box::new(MathExpr::BinOp(
+                    BinMathOp::Add,
+                    Box::new(MathExpr::Number(1.)),
+                    Box::new(MathExpr::BinOp(
+                        BinMathOp::Mult,
+                        Box::new(MathExpr::Number(2.)),
+                        Box::new(MathExpr::Number(3.))
+                    ))
+                )),
+                Box::new(MathExpr::BinOp(
+                    BinMathOp::Pow,
+                    Box::new(MathExpr::Number(5.)),
+                    Box::new(MathExpr::Number(10.))
+                ))
+            )
+        );
+    }
+}
diff --git a/src/math/tokenizer.rs b/src/math/tokenizer.rs
new file mode 100644
index 0000000..b4fd039
--- /dev/null
+++ b/src/math/tokenizer.rs
@@ -0,0 +1,125 @@
+use std::iter::Peekable;
+
+use thiserror::Error;
+
+use crate::math::{MathToken, Number};
+
+pub fn tokenize(input: &str) -> Result<Vec<MathToken>, MathTokenizerError> {
+    let mut tokens = Vec::new();
+    let mut chars = input.char_indices().peekable();
+    loop {
+        match chars.next() {
+            Some((_, ' ')) => { /* Spaces can be ignored in the general case. */ }
+            Some((_, '(')) => tokens.push(MathToken::LParen),
+            Some((_, ')')) => tokens.push(MathToken::RParen),
+            Some((_, '+')) => tokens.push(MathToken::Plus),
+            Some((_, '-')) => tokens.push(MathToken::Minus),
+            // TODO: Integer division with double //
+            Some((_, '/')) => tokens.push(MathToken::Slash),
+            Some((_, '*')) => match chars.peek() {
+                Some((_, '*')) => {
+                    chars.next();
+                    tokens.push(MathToken::DoubleStar)
+                }
+                _ => tokens.push(MathToken::Star),
+            },
+            Some((_, '^')) => tokens.push(MathToken::Caret),
+            Some((start_idx, c)) if c.is_alphabetic() => {
+                // This is an yet unknown symbol, call the helper to find its end and return the
+                // end index. Then take a slice of that symbol and store it.
+                let end_idx = tokenize_sym(&mut chars, input.len());
+                tokens.push(MathToken::Sym(&input[start_idx..end_idx]));
+            }
+            Some((start_idx, c)) if c.is_ascii_digit() || c == '.' => {
+                let end_idx = tokenize_number(c == '.', &mut chars, input.len());
+                let number: Number = input[start_idx..end_idx]
+                    .parse()
+                    .map_err(|_| MathTokenizerError::InvalidNumber(&input[start_idx..end_idx]))?;
+                tokens.push(MathToken::Number(number));
+            }
+            Some((_, c)) => {
+                return Err(MathTokenizerError::InvalidChar(c));
+            }
+
+            // No more chars, so we are done
+            None => break,
+        }
+    }
+
+    Ok(tokens)
+}
+
+fn tokenize_sym(
+    chars: &mut Peekable<impl Iterator<Item = (usize, char)>>,
+    input_end_idx: usize,
+) -> usize {
+    loop {
+        match chars.peek() {
+            // Alphabetic chars can be symbols, so continue on.
+            Some((_, c)) if c.is_alphabetic() => {
+                chars.next();
+            }
+            // Anything other then alphabetic chars means end of symbol
+            Some((end_idx, _)) => return *end_idx,
+            // If we reach the end of the string, that is the end of the symbol
+            None => return input_end_idx,
+        }
+    }
+}
+
+fn tokenize_number<'a>(
+    first_is_dot: bool,
+    chars: &mut Peekable<impl Iterator<Item = (usize, char)>>,
+    input_end_idx: usize,
+) -> usize {
+    let mut has_seen_dot = first_is_dot;
+    loop {
+        match chars.peek() {
+            Some((_, '.')) if !has_seen_dot => {
+                has_seen_dot = true;
+                chars.next();
+            }
+            Some((_, c)) if c.is_ascii_digit() => {
+                chars.next();
+            }
+            Some((end_idx, _)) => return *end_idx,
+            None => return input_end_idx,
+        }
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum MathTokenizerError<'a> {
+    #[error("Invalid character '{0}' in input")]
+    InvalidChar(char),
+    #[error("Invalid number \"{0}\" in input")]
+    InvalidNumber(&'a str),
+}
+
+#[cfg(test)]
+mod test {
+    use crate::math::MathToken::*;
+    use crate::math::tokenizer::tokenize;
+
+    #[test]
+    fn basic_examples() {
+        assert_eq!(tokenize("").unwrap(), vec![]);
+        assert_eq!(tokenize("1").unwrap(), vec![Number(1.)]);
+        assert_eq!(tokenize("1.0").unwrap(), vec![Number(1.)]);
+        assert_eq!(tokenize(".1").unwrap(), vec![Number(0.1)]);
+        assert_eq!(tokenize("1+1").unwrap(), vec![Number(1.), Plus, Number(1.)]);
+        assert_eq!(
+            tokenize("1 + 1").unwrap(),
+            vec![Number(1.), Plus, Number(1.)]
+        );
+        assert_eq!(
+            tokenize(" 1 + 1 ").unwrap(),
+            vec![Number(1.), Plus, Number(1.)]
+        );
+
+        assert_eq!(
+            tokenize("(1+1)").unwrap(),
+            vec![LParen, Number(1.), Plus, Number(1.), RParen]
+        );
+    }
+}
diff --git a/src/modules/desktop.rs b/src/modules/desktop.rs
index e6049de..54fe518 100644
--- a/src/modules/desktop.rs
+++ b/src/modules/desktop.rs
@@ -4,10 +4,7 @@ use std::{
 };
 
 use gtk::{
-    gio::{
-        AppInfo, DesktopAppInfo, Icon,
-        prelude::{AppInfoExt, DesktopAppInfoExtManual},
-    },
+    gio::{AppInfo, DesktopAppInfo, Icon, prelude::AppInfoExt},
     prelude::BoxExt,
 };
 use nucleo_matcher::{