centl

A calculator first, a language when needed.

CENTL is a calculator-first numerical language. Write mathematics directly, interactively or in scripts, without programming ceremony. It is exact by default, explicit about approximation, and never prints an unjustified digit.

You should not need to become a programmer to calculate or abandon mathematical rigor to program.

Principles

• Typing an expression produces an answer immediately.
• A script is simply a saved sequence of calculator expressions and definitions.
• Ordinary mathematics requires no imports, boilerplate, entry points, or type declarations.
• Integers, decimals, and fractions are exact by default.
• Approximation and rounding are always visible and intentional.
• Advanced capabilities appear gradually without changing the basic language.
• Error messages explain the mathematics, not compiler internals.

Try it

Install a native Linux or macOS release without a compiler toolchain:

curl -fsSLO https://raw.githubusercontent.com/chasebryan/centl/main/install
less install
sh install
centl 'solve(x^2 - 5*x + 6 = 0, x)'

On Windows PowerShell:

Invoke-WebRequest https://raw.githubusercontent.com/chasebryan/centl/main/install.ps1 -OutFile install.ps1
Get-Content .\install.ps1
Unblock-File .\install.ps1
.\install.ps1
centl 'solve(x^2 - 5*x + 6 = 0, x)'

From a source checkout with the development toolchain installed:

make test
./centl '0.1 + 0.2'
./centl 'diff(x^3 + 2*x + 1, x)'
./centl 'factor(x^2 - 1)'
./centl 'solve(x^2 - 5*x + 6 = 0, x)'
./centl 'sum(k^2, k = 1, 100)'
./centl 'distance(0, 0, 3, 4)'
./centl 'approx(sin(pi / 6), 20)'

3/10
3 * x^2 + 2
(x - 1) * (x + 1)
x in {2, 3}
338350
5
≈ [0.49999999999999999999, 0.50000000000000000001]

Run ./centl for the calculator, ./centl --syntax for every implemented form, ./centl --file path for a script, ./centl --serve for persistent JSON Lines, or ./centl --mcp as a local AI tool. Mathematical output is colored when written to a terminal; use --color=always, --no-color, or NO_COLOR to control it.

Calculator sessions and scripts remember immutable definitions written as r = 3 or f(x) = x^2 + 1.

Design

CENTL is in early development. See the architecture, complete syntax sheet, numerical contract, calculus syntax, algebra syntax, mathematical functions, exact finite iteration, installation and binary releases, verification boundary, machine protocol, MCP adapter, and roadmap.

License

SPDX-License-Identifier: AGPL-3.0-or-later