calc.nvim

Work in progress. Interactive symbolic RPN calculator for Neovim powered by SymPy.

Features

• RPN stack-based symbolic mathematics
• LaTeX input and output via latex2sympy2
• Environment variables for storing and recalling expressions
• Stack operations: dup, drop, swap, pick, undo
• Calculus: differentiation, determinant
• Algebra: expand, factor
• Implicit multiplication support (2x, (a-1)(a+1))
• Rich display with virtual text, extmarks, and LaTeX conceal
• Undo history for the stack
• Inline help (?)
• Healthcheck (:checkhealth calc)

Requirements

• Neovim 0.9+
• Python 3 with pynvim, sympy
• latex2sympy2 (optional, for LaTeX push)

Installation

lazy.nvim

{
  "splyashka/calc.nvim",
  build = ":UpdateRemotePlugins",
  init = function()
    vim.g.python3_host_prog = vim.fn.expand("~/.virtualenvs/neovim/bin") .. "/python3"
  end,
  keys = {
    { "<leader>cl", ":CalcPushLatexVisual<CR>", desc = "Push LaTeX selection", mode = "x" },
  },
}

Run :Calc to open the calculator window. Run :Calc again to close it.

Note: Make sure your Python 3 host (set via g:python3_host_prog) has pynvim and sympy installed. latex2sympy2 is optional (needed for LaTeX push). Run :checkhealth calc after installation to verify.

Usage

Commands

Command	Effect
:Calc <op>	Execute operation (open window if closed)
:CalcToggle	Open/close the calculator window
:CalcHelp	Show help float window
+, -, *, /	Pop top 2, push result
dup	Duplicate top of stack
drop	Remove top of stack
swap	Swap top 2 elements
pick N	Push copy of Nth element (0-indexed from top)
undo	Restore previous stack state
!	Store: pop a Symbol (name), pop next value, save to env
@	Substitute: pop a Symbol, pop an expression, substitute from env
eval	Substitute all env variables into the top expression
diff sym1 ...	Differentiate top expression wrt given symbols
expand	Expand top expression
factor	Factor top expression
det	Determinant of top expression (must be a matrix)
(any other value)	Push it as a SymPy expression

Buffer keymaps (normal mode)

Key	Action
+, -, *, /	Add, subtract, multiply, divide
<CR>	Duplicate top
.	Repeat last command
dd / <BS>	Drop top
!	Store in env
yl	Copy LaTeX of expression under cursor
I	Open floating LaTeX input window
s	Swap top 2
u	Undo
?	Show help
0 – 9	Push digit
i	Enter :Calc command
ad	Enter :Calc diff (differentiate)
ax	Expand
af	Factor
vD	Compute determinant

Visual mode

Key	Action
<leader>cl	Push visual selection as LaTeX

Examples

Differentiate — type :Calc diff x, or press ad and type x:

x^2 + 3*x  →  2*x + 3

Matrix determinant — push a sympy matrix, press vD:

Matrix([[1, 2], [3, 4]])  →  -2

Expand and factor — press ax or af:

(x-1)*(x+1)  →  x^2 - 1
x^2 - 1     →  (x-1)*(x+1)

Store and recall — push a value, then push a symbol on top and press !:

42       — push value
ans      — push symbol
!        — store (pops symbol then value) → env["ans"] = 42

ans + 1  — push expression
ans      — push symbol
@        — subst (pops symbol then expression) → 43

LaTeX input — press I, type LaTeX in the float buffer, press <CR> to commit:

\frac{d}{dx} x^2  →  2*x

Roadmap

• K hover for info about the expression under cursor
• Configurable keymaps

License

MIT