diff --git a/Cargo.lock b/Cargo.lock
index 82b0e03..a2ef1d0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -43,7 +43,6 @@ version = "0.1.0"
 dependencies = [
  "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 00f9896..05b992c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,5 @@ edition = "2018"
 [dependencies]
 bitflags = "1.1.0"
 lazy_static = "1.4.0"
-libc = "0.2"
 # Rust wrappers for C/POSIX headers
 nix = "0.15.0"
diff --git a/src/editor.rs b/src/editor.rs
index deeb303..ce3ec8a 100644
--- a/src/editor.rs
+++ b/src/editor.rs
@@ -435,9 +435,11 @@ impl Editor {
             None
         };
         let row = &mut rows[index];
+        let render_len = row.render.len();
+        
 
         // Reset the highlighting of the row
-        row.highlight = vec![Highlight::Normal; row.render.len()];
+        row.highlight = vec![Highlight::Normal; render_len];
 
         if self.syntax.is_none() {
             return;
@@ -462,7 +464,7 @@ impl Editor {
 
         let mut i = 0;
         let bytes = row.render.clone().into_bytes();
-        'outer: while i < row.render.len() {
+        while i < render_len {
             let c = bytes[i] as char;
             let prev_highlight = if i > 0 {
                 row.highlight[i - 1]
@@ -472,12 +474,12 @@ impl Editor {
 
             // Single line comments
             if scs.len() > 0 && !in_string && !in_comment {
-                let range = get_slice_range(i as usize, scs.len(), row.render.len());
+                let range = get_slice_range(i, scs.len(), render_len);
                 if &row.render[range] == scs {
                     // Pretty simple, highlight from the match to the end of the line
                     highlight_range(
                         &mut row.highlight,
-                        i as usize..row.render.len(),
+                        i..render_len,
                         Highlight::LineComment,
                     );
                     break;
@@ -486,16 +488,16 @@ impl Editor {
 
             // Multi-line comments
             if mcs.len() > 0 && mce.len() > 0 && !in_string {
-                let mce_slice_range = get_slice_range(i as usize, mce.len(), row.render.len());
-                let mcs_slice_range = get_slice_range(i as usize, mcs.len(), row.render.len());
+                let mce_range = get_slice_range(i, mce.len(), render_len);
+                let mcs_range = get_slice_range(i, mcs.len(), render_len);
                 if in_comment {
-                    row.highlight[i as usize] = Highlight::MultiLineComment;
+                    row.highlight[i] = Highlight::MultiLineComment;
 
                     // End of a comment
-                    if &row.render[mce_slice_range.clone()] == mce {
+                    if &row.render[mce_range.clone()] == mce {
                         highlight_range(
                             &mut row.highlight,
-                            mce_slice_range,
+                            mce_range,
                             Highlight::MultiLineComment,
                         );
 
@@ -507,11 +509,11 @@ impl Editor {
                         i += 1;
                         continue;
                     }
-                } else if &row.render[mcs_slice_range.clone()] == mcs {
+                } else if &row.render[mcs_range.clone()] == mcs {
                     // Start of a multi-line comment
                     highlight_range(
                         &mut row.highlight,
-                        mcs_slice_range,
+                        mcs_range,
                         Highlight::MultiLineComment,
                     );
 
@@ -527,10 +529,10 @@ impl Editor {
                 .contains(SyntaxFlags::HIGHLIGHT_STRINGS)
             {
                 if in_string {
-                    row.highlight[i as usize] = Highlight::String;
+                    row.highlight[i] = Highlight::String;
                     // Don't end highlighting for a string on an escaped quote
-                    if c == '\\' && i + 1 < row.render.len() {
-                        row.highlight[i as usize + 1] = Highlight::String;
+                    if c == '\\' && i + 1 < render_len {
+                        row.highlight[i + 1] = Highlight::String;
                         i += 2;
                         continue;
                     }
@@ -547,7 +549,7 @@ impl Editor {
                     if (c == '"' || c == '\'') && prev_separator {
                         in_string = true;
                         str_start = c;
-                        row.highlight[i as usize] = Highlight::String;
+                        row.highlight[i] = Highlight::String;
                         i += 1;
                         continue;
                     }
@@ -562,7 +564,7 @@ impl Editor {
                 if (c.is_ascii_digit() && (prev_separator || prev_highlight == Highlight::Number))
                     || (c == '.' && prev_highlight == Highlight::Number)
                 {
-                    row.highlight[i as usize] = Highlight::Number;
+                    row.highlight[i] = Highlight::Number;
                     i += 1;
                     prev_separator = false;
                     continue;
@@ -572,10 +574,14 @@ impl Editor {
             // Keywords
             if prev_separator {
                 for &keyword in keywords1 {
-                    let search_range = get_slice_range(i as usize, keyword.len(), row.render.len());
+                    if i + keyword.len() >= render_len {
+                        continue;
+                    }
 
-                    let next_char_offset = i as usize + keyword.len() + 1;
-                    let is_end_of_line = next_char_offset >= row.render.len();
+                    let search_range = get_slice_range(i, keyword.len(), render_len);
+
+                    let next_char_offset = i + keyword.len() + 1;
+                    let is_end_of_line = next_char_offset >= render_len;
                     let next_char = if is_end_of_line {
                         '\0'
                     } else {
@@ -589,10 +595,14 @@ impl Editor {
                 }
 
                 for &keyword in keywords2 {
-                    let search_range = get_slice_range(i as usize, keyword.len(), row.render.len());
+                    if i + keyword.len() >= render_len {
+                        continue;
+                    }
 
-                    let next_char_offset = i as usize + keyword.len() + 1;
-                    let is_end_of_line = next_char_offset >= row.render.len();
+                    let search_range = get_slice_range(i, keyword.len(), render_len);
+
+                    let next_char_offset = i + keyword.len() + 1;
+                    let is_end_of_line = next_char_offset >= render_len;
                     let next_char = if is_end_of_line {
                         '\0'
                     } else {
@@ -1579,8 +1589,9 @@ where
     match res {
         Ok(value) => value,
         Err(e) => {
+            print!("\x1b[2J");
+            print!("\x1b[H");
             disable_raw_mode();
-            println!("\r\n");
             panic!("{:?}", e);
         }
     }
@@ -1603,7 +1614,19 @@ mod tests {
 
     #[test]
     fn is_separator_works() {
-        assert_eq!(is_separator(' '), true);
-        assert_eq!(is_separator('_'), false);
+        // Check each explicit character
+        for ch in ",.()+-/*=~%<>[];".chars() {
+            assert_eq!(is_separator(ch), true);
+        }
+
+        // Check each whitespace character
+        for ch in " \t\n\x0c".chars() {
+            assert_eq!(is_separator(ch), true, "Character {:#} should be a separator", ch as u8);
+        }
+
+        // Letters are not separators!
+        for ch in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_".chars() {
+            assert_eq!(is_separator(ch), false);
+        }
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 2fe4c9d..1a0746e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,7 +9,7 @@ mod terminal_helpers;
 
 use crate::editor::Editor;
 use crate::terminal_helpers::*;
-use libc::STDIN_FILENO;
+use nix::libc::STDIN_FILENO;
 use nix::sys::termios::Termios;
 use std::env;
 use std::io::Error;
diff --git a/src/terminal_helpers.rs b/src/terminal_helpers.rs
index 7495fde..da3f3c8 100644
--- a/src/terminal_helpers.rs
+++ b/src/terminal_helpers.rs
@@ -1,8 +1,8 @@
 //! # Helpers
 //!
 //! Various functions calling C wrappers to get/set terminal functionality
-use libc::ioctl;
-use libc::{c_ushort, STDIN_FILENO, STDOUT_FILENO, TIOCGWINSZ};
+use nix::libc::ioctl;
+use nix::libc::{c_ushort, STDIN_FILENO, STDOUT_FILENO, TIOCGWINSZ};
 use nix::sys::termios;
 use nix::sys::termios::{
     ControlFlags, InputFlags, LocalFlags, OutputFlags, SpecialCharacterIndices, Termios,