Gridline ✨

Gridline is a proof-of-concept terminal spreadsheet with Rhai support. Cells can contain numbers, text, or formulas powered by the Rhai scripting language. Your sheet lives in a plain text file, and your reusable logic can live in a separate .rhai functions file.

What you get (today):

• TUI grid with a formula bar and command mode
• A1-style references in formulas (=A1 + B2) and range functions (=SUM(A1:B5))
• Dependency tracking and recalculation
• Load/reload user functions from a .rhai file (-f at startup, :source at runtime)
• Two keymaps: vim (default) and emacs
• Plain text storage format (one cell per line)
• Simple plotting in a modal (bar/line/scatter)

Project status: this is a POC. Expect rough edges (especially around plotting and any non-trivial spreadsheet ergonomics).

Why it's fun:

• 🧾 Plain-text sheets you can diff and version
• 🧠 Formulas are real Rhai scripts (with spreadsheet sugar)
• 📈 Quick plots right in the terminal

Screenshots

Quick Start 🚀

Build and run:

cargo run

Open an example file:

cargo run -- examples/test.grid

Load custom Rhai functions at startup:

cargo run -- -f examples/functions.rhai examples/test.grid

Reload / load functions at runtime:

:source examples/functions.rhai

Cell Input Rules 🧾

Gridline interprets cell input like this:

• empty / whitespace => empty cell
• leading = => formula (Rhai script; stored without the =)
• quoted "text" => text (quotes stripped)
• otherwise, parseable as f64 => number
• else => text

Examples:

A1: 10
A2: "hello"
A3: =A1 * 2
A4: =SUM(A1:A3)

Formulas (Rhai + Spreadsheet Sugar) 🧠

Inside formulas:

• A1 becomes cell(0, 0) (0-indexed internally)
• @A1 becomes value(0, 0) (typed access: numbers/text/bools)
• SUM(A1:B5) becomes sum_range(0, 0, 4, 1)

Arrays "spill" down the column. If you need to do an in-place operation that returns () (like Rhai's Array.sort()), use OUTPUT:

A1: 30
A2: 10
A3: 20
B1: =OUTPUT(VEC(A1:A3), |v| { v.sort(); v })

Typed refs are useful when a referenced cell contains text (or a formula that returns text):

B1: =if C1 > 100 { "expensive" } else { "cheap" }
A1: =len(@B1)

Built-in range functions (ALL CAPS):

• SUM, AVG, COUNT, MIN, MAX
• BARCHART, LINECHART, SCATTER
• VEC (convert a range to an array; respects direction: VEC(A3:A1) returns [A3, A2, A1])

Other built-ins:

• RAND() - random float in [0.0, 1.0)
• RANDINT(min, max) - random integer in [min, max] inclusive

Custom Functions Example 🧩

Create a .rhai file:

fn fib(n) {
  if n < 2 { n } else { fib(n - 1) + fib(n - 2) }
}

Load it (either -f or :source), then use it in a cell:

A1: "Fibonacci"
B1: 10
C1: =fib(B1)

Plotting 📈

Plotting works by making a formula cell return a tagged plot spec. The grid shows a placeholder (e.g. <BAR>), and you can open the plot modal.

Example (examples/plot.grid):

C1: =SCATTER(A1:B5, "title", "xaxis", "yaxis")
D1: =BARCHART(B1:B5)

Open the plot modal:

• Vim keymap: P
• Emacs keymap: M-p

Commands ⌨️

Command mode:

• Vim: :
• Emacs: M-x

Useful commands:

• :w or :w <path> save
• :q quit (warns if modified)
• :q! force quit
• :wq save and quit
• :e <path> open file
• :goto A100 (alias :g A100) jump to a cell
• :colwidth 15 set current column width
• :colwidth A 15 set a specific column width
• :source <file.rhai> (alias :so) load functions; :so reloads the last functions file

Keymaps 🗺️

Select keybindings:

gridline --keymap vim
gridline --keymap emacs

Status bar has an always-on cheat sheet, but the core controls are:

Vim:

• hjkl move, i/Enter edit, Esc cancel
• v visual select, y yank, p paste
• :w save, :q quit

Emacs:

• C-n/p/f/b move, Enter edit, C-g cancel
• C-SPC set mark (visual), M-w copy, C-y paste
• C-s save

File Format 📝

Gridline files are plain text. Non-empty, non-comment lines look like:

CELLREF: VALUE

Comments start with #. Values follow the same input rules as interactive editing.

Development 🔧

cargo fmt
cargo clippy --all-targets -- -D warnings
cargo test

License 📜

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)