# Decimo v0.9.0 — now with a CLI calculator and Python bindings **URL:** \ **Category:** Community Showcase\ **Created:** [March 28, 2026, 11:53am UTC](https://forum.modular.com/t/decimo-v0-9-0-now-with-a-cli-calculator-and-python-bindings/2899 "2026-03-28T11:53:09Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![forfudan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/forfudan/32/925_2.png) [@forfudan](https://forum.modular.com/u/forfudan)\ **Post date:** [March 28, 2026, 11:53am UTC](https://forum.modular.com/t/decimo-v0-9-0-now-with-a-cli-calculator-and-python-bindings/2899/1 "2026-03-28T11:53:09Z")
[![Version](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/1/13b0c02dc2200938de25f6dd83a75940c353ae0c.svg)](https://github.com/forfudan/decimo/releases) [![Mojo](https://us1.discourse-cdn.com/flex001/uploads/modular/original/1X/4f8660dae62554838f90625d71cb0c1da06ad174.svg)](https://docs.modular.com/mojo/manual/) [![pixi](https://us1.discourse-cdn.com/flex001/uploads/modular/original/1X/2ab5f35faf7b38108c400ffe2449a463e267ab6f.svg)](https://prefix.dev/channels/modular-community/packages/decimo) Hi Mojicians, [Decimo](https://github.com/forfudan/decimo) (previously known as DeciMojo) just hit **v0.9.0** (compatible with **Mojo v0.26.2** ) and is available right away via: ```auto pixi add decimo ``` This time around, I wanted to experiment with a couple of features and see how far Mojo can go as a general-purpose language. Let me walk you through what’s new in Decimo. ## CLI Arbitrary-Precision Calculator This is probably the most fun part. Since [ArgMojo](https://github.com/forfudan/argmojo) is now fully functional (supports subcommands, autocompletion, interactive prompting, compile-time validation — basically everything you’d expect from a CLI framework), I thought: why not dogfood it and build an actual app? So `decimo` is now also a **command-line calculator**. You type an expression, it evaluates it with arbitrary precision. It’s got a proper tokenizer, a shunting-yard parser, and an RPN evaluator under the hood — all in pure Mojo, compiled to a single native binary with zero runtime dependencies. ```sh % decimo 1/3+1/7 0.47619047619047619047619047619047619047619047619048 % decimo "sqrt(2)" -p 50 1.4142135623730950488016887242096980785696718753769 % decimo "pi * sqrt(11.1^15)" --engineering -p 100 217.3062481188781475831859094865556029360927703474185717693262086138432884379636518929905574763204566E+6 ``` You can also configure output formatting — scientific notation (`-s`), engineering notation (`-e`), digit delimiters (`-d`), rounding modes (`-r`), precision (`-p`), and more. Here’s a quick demo of calculating an expression: ![Calculation demo](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/7/7f89c34f658d6b7b3b2a87c8161b991c4ad98e05.gif) And here’s what `decimo -h` looks like (automatically generated by [ArgMojo](https://github.com/forfudan/argmojo)): ![Help output](https://us1.discourse-cdn.com/flex001/uploads/modular/original/2X/7/7ba4eaa2c10b3f9848b9c49befa883dbcfd65cb4.gif) Honestly, it makes me really happy to see that Mojo can be used as an application programming language — building real tools with proper argument parsing, coloured error messages, the whole thing. It just works. * * * ## Python Bindings Also new in this release: Decimo now has **Python bindings** via Mojo’s `PythonModuleBuilder`. The `BigDecimal` type is exposed as a native CPython extension module (`_decimo.so`) with a Pythonic `Decimal` wrapper. It’s available on PyPI: **[pypi.org/project/decimo](https://pypi.org/project/decimo/)** ```python from decimo import Decimal a = Decimal("1.234567890123456789012345678901234567890") b = Decimal("9.876543210987654321098765432109876543210") print(a + b) print(a * b) ``` Still at an early stage — no pre-built wheels yet — but it already proves that Mojo’s interoperability with Python is very strong. Calling Mojo from Python and vice versa is becoming genuinely practical. * * * ## Other Highlights - A bunch of new `BigDecimal` methods aligned with Python’s `decimal.Decimal` and IEEE 754: `as_tuple()`, `adjusted()`, `fma()`, `scaleb()`, `same_quantum()`, `copy_abs()`, `copy_sign()`, ` __float__ ()`, engineering notation, digit-group delimiters, and the `ROUND_HALF_DOWN` rounding mode (7 modes total now). - `TOMLMojo` is merged into Decimo as the sub-package `decimo.toml`. - Codebase updated to **Mojo v0.26.2** syntax (`byte=` slicing, `out` parameter convention, etc.). Full changelog: [github.com/forfudan/decimo/releases](https://github.com/forfudan/decimo/releases) * * * I’m very optimistic about the future of Mojo. Each release feels like a step closer to a language that’s both fast _and_ pleasant to build real software with. As always, feedback and issues are welcome on the [repo](https://github.com/forfudan/decimo). Happy hacking! 🔥 ---
**Author:** ![Photon](https://avatars.discourse-cdn.com/v4/letter/p/b5a626/32.png) [@Photon](https://forum.modular.com/u/Photon)\ **Post date:** [March 31, 2026, 5:24pm UTC](https://forum.modular.com/t/decimo-v0-9-0-now-with-a-cli-calculator-and-python-bindings/2899/2 "2026-03-31T17:24:19Z")
The calculator is a pretty cool “pythonic” addition 🙂 ---
**Author:** ![forfudan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/forfudan/32/925_2.png) [@forfudan](https://forum.modular.com/u/forfudan)\ **Post date:** [April 1, 2026, 9:41am UTC](https://forum.modular.com/t/decimo-v0-9-0-now-with-a-cli-calculator-and-python-bindings/2899/3 "2026-04-01T09:41:47Z")
Yes, finally we are all Pythonistas 😃 ---
**Author:** ![system](https://us1.discourse-cdn.com/flex001/uploads/modular/original/1X/2751e0fbdc595a99718b216730957e9db4448cfd.jpeg) [@system](https://forum.modular.com/u/system)\ **Post date:** [September 28, 2026, 9:42am UTC](https://forum.modular.com/t/decimo-v0-9-0-now-with-a-cli-calculator-and-python-bindings/2899/4 "2026-09-28T09:42:37Z")
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