diff --git a/abacus-core/src/engine.rs b/abacus-core/src/engine.rs
index f864b9b..38bbb7d 100644
--- a/abacus-core/src/engine.rs
+++ b/abacus-core/src/engine.rs
@@ -10,6 +10,8 @@ impl<'a> Default for Engine<'a> {
     fn default() -> Self {
         let mut engine = rhai::Engine::new();
         engine.set_fast_operators(false);
+        engine.register_static_module("physics", rhai::exported_module!(physics).into());
+        engine.register_static_module("math", rhai::exported_module!(math).into());
         dataframe::setup_engine(&mut engine);
 
         Self {
@@ -58,7 +60,7 @@ impl Default for Output {
 impl PartialEq for Output {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {
-            (Self::Scalar(l0), Self::Scalar(r0)) => l0.to_string() == r0.to_string(),
+            (Self::Scalar(l0), Self::Scalar(r0)) => *l0.to_string() == *r0.to_string(),
             (Self::DataFrame(l0), Self::DataFrame(r0)) => l0 == r0,
             (Self::Series(l0), Self::Series(r0)) => l0 == r0,
             (Self::Error(l0), Self::Error(r0)) => l0 == r0,
@@ -88,12 +90,39 @@ impl Output {
     }
 }
 
+use rhai::plugin::*;
+
+#[rhai::export_module]
+mod physics {
+    pub const PLANK: f64 = 6.626e-34;
+    pub const G: f64 = 6.67430e-11;
+    pub const COULUMN: f64 = 8.987;
+    pub const STEFAN_BOLTZMANN: f64 = 5.670e-8;
+    pub const BOLTZMANN: f64 = 1.380650e23;
+    pub const C: f64 = 299792458.0;
+    pub const AVOGADRO: f64 = 6.02214076e23;
+
+    pub const ATOMIC_MASS: f64 = 1.66053906660e-27;
+    pub const ELECTRON_MASS: f64 = 9.1093837015e-31;
+    pub const PROTON_MASS: f64 = 1.67262192369e-27;
+    pub const NEUTRON_MASS: f64 = 1.67492749804e-27;
+    pub const HUBBLE: f64 = 69.3;
+}
+
+#[rhai::export_module]
+mod math {
+    pub const PI: f64 = std::f64::consts::PI;
+    pub const E: f64 = std::f64::consts::E;
+    pub const SQRT2: f64 = std::f64::consts::SQRT_2;
+    pub const TAU: f64 = std::f64::consts::TAU;
+}
+
 #[cfg(test)]
 pub mod tests {
     use super::*;
 
     pub fn process(script: &str) -> Output {
-        let mut engine = Engine::default();
+        let mut engine = super::Engine::default();
         engine.process_script(script)
     }
 }
diff --git a/abacus-ui/src/data/editor_data.rs b/abacus-ui/src/data/editor_data.rs
index 24c590a..5cb3a36 100644
--- a/abacus-ui/src/data/editor_data.rs
+++ b/abacus-ui/src/data/editor_data.rs
@@ -330,6 +330,9 @@ impl EditorData {
     }
 
     pub fn current_line_index(&self) -> usize {
+        if self.cursor_pos == 0 {
+            return 0;
+        }
         self.content.char_to_line(self.cursor_pos)
     }