Spreadsheet

A terminal based spreadsheet editor and calculator.

It allows you to quickly perform spreadsheet calculations - right in your terminal!

How-to

Basic Usage

Open a file: ./spreadsheet sheet.csv (or without arguments for a new untitled spreadsheet).

Navigation (normal mode):

• Move cursor: arrow keys or vim keys (hjkl)
• Edit cell: press Enter
• Save: press s
• Quit: press q

Editing cells (insert mode):

• Type your value (integer, text, or formula starting with =)
• Press Enter to commit and return to normal mode
• Press ESC to cancel without saving
• Press Backspace to delete characters

Cell picking (for formulas): While in insert mode, press Ctrl+Space to enter picking mode. This lets you visually select cells to insert into your formula:

1. Navigate to the cell you want (arrow keys or hjkl)
2. Press Enter once to mark the start of selection
3. For a single cell: press Enter again to insert it (e.g., A1)
4. For a range: navigate to the end cell, then press Enter to insert the range (e.g., A1:B3)
5. Press ESC to cancel picking and return to editing

Functional cells

Parsing

For fun, the parsing of the formulas is done using Odin's own tokenizer and parser. This means that you are actually writing a subset of Odin that is valid Excel Formula Language.

The parsing is simple, first = is stripped from the beginning of the expression. Then the expression is tokenized and fed into the parser. This produces an abstract syntax tree (specified here), which is then evaluated using simple an AST walking interpreter.

How are ranges parsed, A1:B3 isn't valid Odin? To solve this, a pre-processing step is first performed to the formula, turning A1:B3 into range(A1, B3).

Dependencies

Functional cells are evaluated in topological order. Meaning, the dependencies of a cell are evaluated before the dependent cell is evaluated. In the following example

A1: 1
B1: =A1
C1: =B1

First B1 is evaluated, then C1.

A hand-rolled topological sort has been implemented for educational purposes, despite Odin having an implementation in the standard library.

Features for MVP

• modal editing
  • normal
  • insert
  • cell label picking
  • visual + copy & paste
• open csv files
• cell types
  • integers
  • formulas
  • strings
  • floats
• calculations
  • evaluate formulas
  • add support for ranges
  • function calling

Future features (?)

• undo/redo
• auto-fill (drag bottom right corner)
• relative (A1), absolute ($A$1), mixed ($A1, A$1) (needed by auto-fill)
• only reevaluate dependent cells
• multi-thread independent evaluation
• multiple sheets
• row filtering
• freeze rows/columns
• cell formatting (colors, font)
• cell manual width and height
• datetime cells
• open excel files
  • xls
  • xlsx