From 5d08f59083f61d6af22c1f18163979c3405fa807 Mon Sep 17 00:00:00 2001
From: Kasper <kasperkh.kh@gmail.com>
Date: Thu, 8 Apr 2021 00:45:52 +0200
Subject: [PATCH] Fix panic when input is empty string

---
 README.md    | 3 ---
 src/lexer.rs | 4 ++++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index a580c6b..95f52a5 100644
--- a/README.md
+++ b/README.md
@@ -91,9 +91,6 @@ It's pretty fast and scales well. In my case, it usually runs in under 0.1ms. Th
 
 To see how fast it is, you can pass the `--debug` flag in CLI, or the `debug` argument to `eval()`.
 
-## Errors
-cpc returns `Result`s with basic strings as errors. Just to be safe, you may want to handle panics (You can do that using `std::panic::catch_unwind`).
-
 ## Dev Instructions
 
 ### Get started
diff --git a/src/lexer.rs b/src/lexer.rs
index a11dba0..f6c6f5d 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -21,6 +21,10 @@ pub const fn is_alphabetic_extended(input: &char) -> bool {
 /// Lex an input string and return a [`TokenVector`]
 pub fn lex(input: &str, allow_trailing_operators: bool, default_degree: Unit) -> Result<TokenVector, String> {
 
+  if input == "" {
+    return Err(format!("Input was empty"))
+  }
+
   let mut input = input.replace(",", ""); // ignore commas
   input = input.to_lowercase();