solva.nvim

solva.nvim brings line-by-line calculation to Neovim.

This project is heavily inspired by the Soulver Mac app.

Write expressions in a normal text buffer, then see results update in a right-side split (or inline virtual text). It supports variables, units, running totals, line references like line3, and common math functions.

Highlights

• Fast line-by-line evaluation in plain text buffers
• Right-side results split (result_mode = "split") or inline virtual text
• Variables with $ syntax: $rent = 2400, then $rent * 12
• Previous result references: ans, _
• Line references: line1, line2, line3, ...
• Running totals: total, subtotal, total in usd
• Unit and temperature conversion: 10 km in mi, 72 f in c
• Date math: today + 3 weeks 2 days, from March 12 to July 30
• Time math: 3:35 am + 9 hours 20 minutes, from 9:15 am to 5:40 pm
• Functions: sqrt, abs, floor, ceil, round, log, ln, sin, cos, tan, gcf(...)
• Continuous auto-eval while typing (scoped to specific filetypes or enabled per-buffer)

Install (lazy.nvim)

{
  dir = "~/path/to/solva.nvim",
  name = "solva_nvim",
  config = function()
    require("solva").setup({
      precision = 6,
      result_prefix = "",
      highlight_group = "Comment",
      result_mode = "split", -- "split" | "virtual_text"
      split_width = 36,

      auto_eval = true,
      auto_eval_debounce_ms = 120,
      auto_eval_filetypes = { "solva" }, -- auto-run only on these filetypes
    })
  end,
}

Quick Start

1. Open a buffer and set :set filetype=solva (or use :SolvaEnable in any buffer).
2. Type:

$subtotal = 129.99
$tax = 8.25%
$subtotal + $subtotal * $tax
ans * 0.9
line3 * 2

10 km in mi
72 f in c
today + 3 weeks 2 days
from March 12 to July 30
3:35 am + 9 hours 20 minutes
from 9:15 am to 5:40 pm

Lunch: 14.50 usd
Coffee: 4.25 usd
total

3. Run :SolvaEvalBuffer (or rely on auto-eval if enabled).

Commands

• :SolvaEvalLine evaluate current line
• :SolvaEval evaluate selected range (visual: :'<,'>SolvaEval)
• :SolvaEvalBuffer evaluate full buffer
• :SolvaClear clear rendered results
• :SolvaOpenSplit open the right-side results split
• :SolvaCloseSplit close the right-side results split
• :SolvaEnable enable Solva for current buffer (auto-eval + split behavior)
• :SolvaDisable disable Solva for current buffer and close/clear results

Expression Guide

Arithmetic

• Operators: + - * / ^
• Parentheses supported
• Implicit multiplication supported: 2(3+4), 10 km
• Percent postfix: 50%, 200 + 10%

Variables

• Assign with $name = expr
• Use with $name
• Example:

$hours = 160
$rate = 95
$hours * $rate

Line References

• Any successfully evaluated line is available as lineN
• Example:

10
20
line1 + line2
line3 * 2

Running Totals

• total and subtotal show current running total
• You can convert totals: total in usd, total in eur
• If value types are incompatible, Solva starts a new subtotal block

Date Math

Supported date expressions:

• today + 3 weeks 2 days
• 2026-03-01 + 45 days
• 2026-03-01 - 2 weeks
• from March 12 to July 30
• from 2026-03-01 to 2026-03-15

Notes:

• from ... to ... returns a day count.
• Month-name dates default to the current year when year is omitted.

Time Math

Supported time expressions:

• 3:35 am + 9 hours 20 minutes
• 14:10 + 45 min
• from 9:15 am to 5:40 pm

Notes:

• Time output is formatted as h:mm am/pm.
• from ... to ... returns a duration (for example 8 hours 25 minutes).

Units and Conversion

Supported groups:

• Length: mm cm m km in ft yd mi
• Mass: g kg oz lb
• Time: s min h day
• Temperature: c f k
• Currency (static placeholders): usd eur gbp jpy

Examples:

10 km in mi
5 lb in kg
72 f in c
$100 + 50 usd
€120 + £10

Functions

• sqrt(x)
• abs(x)
• floor(x)
• ceil(x)
• round(x)
• log(x) (base 10)
• ln(x) (natural log)
• sin(x), cos(x), tan(x)
• gcf(a, b, c, ...) greatest common factor for integers

Configuration

require("solva").setup({...}) supports:

• precision (number, default 6)
• max_line_length (number, default 10000)
• max_tokens (number, default 2048)
• max_parse_depth (number, default 128)
• max_lines_per_eval (number, default 2000)
• result_prefix (string, default "")
• highlight_group (string, default "Comment")
• result_mode ("split" or "virtual_text", default "split")
• split_width (number, default 36)
• auto_eval (boolean, default false)
• auto_eval_debounce_ms (number, default 120)
• auto_eval_events (list, default { "TextChanged", "TextChangedI", "InsertLeave", "BufEnter" })
• auto_eval_filetypes (list, default { "solva" })
• buffer_enable_var (string, default "solva_enabled")

Notes

• Currency rates are static placeholders for local workflow and are not fetched live.
• This is an MVP parser focused on practical inline calculation workflow inside Neovim.

Testing

Run the regression suite:

make test

Run coverage:

make coverage-report

Current tests cover:

• Core arithmetic and functions
• Variables, ans, and lineN references
• Units and conversions
• Totals/subtotals and labels
• Date and time math
• Error paths for invalid expressions