github-linguist/linguist

Excel Formula Language

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#7886 opened on Mar 29, 2026

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Description

Language name

The Excel Formula Language is likely the most popular programming language and with the introduction of LAMBDA, it's even turing complete.

Since fomulas live inside of Excel they are rarely seen as source code, however there are instances of people sharing formulas/lambdas on GitHub, so adding support for it on GitHub could be considered.

URL of example repository

These repos are using simply the .txt file extension:

This repo puts the formula in the README directly: https://github.com/UoLeevi/excel

OA Robot is using the .lambda file extension: https://github.com/oehmauto/OARobot/tree/main/Getting%20Started%20Command%20Collection.xlsm%20README/Lambdas

A gist with Excel Lamda functions: https://gist.github.com/wynhopkins/2efdf218ed78be03a0a082ff6a99dad1

URL of syntax highlighting grammar

https://github.com/miguelangelcdm/excel-formula-formatter (Note that the extension is advocating for the .xlf extension)

Most popular extensions

.txt with 1.7k+ results .xlf with ~74 results .lambda with ~100 results .excel with 350+ results

(some search queries might need some improvement for more accurate results)

Detected language

None or XML (when using the .xlf extension)

Contributor guide

Tech stack
ruby
Domain
tooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic understanding of RubyFamiliarity with linguist's language detectionKnowledge of regex and syntax highlighting
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Review the linguist documentation for adding a new language, especially the CONTRIBUTING.md. The issue provides a link to the excel formula formatter grammar that can be used as a starting point. Implement the grammar and update the languages.yml file with appropriate extensions, and ensure tests pass. No linked PRs or comments to consider.