It started with a simple question: how hard could it be to build a text editor? Turns out, harder than I expected, but incredibly rewarding. Hecto is my vim-inspired terminal editor written in Rust.

Why Build an Editor?

As a developer, I spend hours in text editors. Understanding how they work felt like a rite of passage. Plus, I’ve always wanted to customize my editor exactly to my liking.

Terminal Control

Modern terminals are surprisingly capable. Using ANSI escape codes, you can:

  • Move the cursor anywhere
  • Clear the screen
  • Change colors
  • Read raw key input

The challenge is doing it portably across macOS, Linux, and Windows.

Raw Mode

Normally, the terminal processes your input (echoing characters, handling Ctrl+C). For an editor, you need “raw mode”:

// Disable canonical mode and echo
let mut termios = Termios::from_fd(STDIN_FILENO)?;
termios.c_lflag &= !(ECHO | ICANON);
tcsetattr(STDIN_FILENO, TCSANOW, &termios)?;

Now every key press comes directly to your program.

The Editor Loop

loop:
    process_input()
    update_screen()
    refresh_display()

At 60fps, this feels responsive even for large files.

Data Structure: The Gap Buffer

For text storage, I use a gap buffer:

struct GapBuffer {
    buffer: Vec<u8>,
    gap_start: usize,
    gap_end: usize,
}

The “gap” is an empty space at the cursor position. Insertions are O(1) (just write into the gap). The gap moves when you navigate.

Vim-Style Modal Editing

Hecto implements:

  • Normal mode: Navigation and commands
  • Insert mode: Typing text
  • Visual mode: Selection

The modal approach feels foreign at first, but becomes incredibly efficient once muscle memory kicks in.

Syntax Highlighting

Basic highlighting uses regex patterns:

  • Keywords (fn, let, mut)
  • Strings and comments
  • Numbers

It’s not tree-sitter level accuracy, but good enough for readability.

What’s Missing

Real editors have:

  • Undo/redo (surprisingly tricky to get right)
  • Multiple cursors
  • Plugin systems
  • LSP integration

Maybe in version 2.0.

Try It

cargo run -- file.txt

Navigation: hjkl or arrow keys Mode switching: i (insert), Esc (normal) Save: :w Quit: :q

Building Hecto taught me to appreciate the complexity hidden in “simple” tools. Every editor, from Notepad to VS Code, solves the same fundamental problems—just with different tradeoffs.