diff --git a/reid/src/lexer.rs b/reid/src/lexer.rs
index 3a1d477..e786ae8 100644
--- a/reid/src/lexer.rs
+++ b/reid/src/lexer.rs
@@ -363,14 +363,17 @@ pub fn tokenize<T: Into<String>>(to_tokenize: T) -> Result<Vec<FullToken>, Error
                 let mut value = NumberType::Decimal(character.to_string());
                 let mut numerics = DECIMAL_NUMERICS;
                 if let Some(second) = cursor.second() {
-                    if cursor.first() == Some('x') && HEXADECIMAL_NUMERICS.contains(&second) {
+                    if cursor.first() == Some('x')
+                        && HEXADECIMAL_NUMERICS
+                            .contains(&second.to_lowercase().next().unwrap_or('.'))
+                    {
                         cursor.next();
                         value = NumberType::Hexadecimal(String::new());
                         numerics = HEXADECIMAL_NUMERICS;
                     }
                 }
                 while let Some(c) = cursor.first() {
-                    if !numerics.contains(&c) {
+                    if !numerics.contains(&c.to_lowercase().next().unwrap_or('.')) {
                         break;
                     }
                     value += c;
diff --git a/reid/tests/e2e.rs b/reid/tests/e2e.rs
index 61e9815..5b16a47 100644
--- a/reid/tests/e2e.rs
+++ b/reid/tests/e2e.rs
@@ -132,3 +132,7 @@ fn ptr_hard_compiles_well() {
 fn loop_hard_compiles_well() {
     test(include_str!("../../examples/loop_hard.reid"), "test", 0);
 }
+#[test]
+fn custom_binop_compiles_well() {
+    test(include_str!("../../examples/custom_binop.reid"), "test", 21);
+}