FML: Freeform Markup Language v0.1

Overview

Freeform Markup Language (FML) is a lightweight, expressive markup language designed to write prompts for large language models (LLMs) using structured XML-style tags and Mustache-style variables. It’s designed for developers who want readable, reusable, and modular prompts without the chaos of raw strings.

Features

- 🧩 Mustache-style variable interpolation: {{ name }}
- 🔁 tag for nesting other .fml files
- 🧪 Simple, testable, and transformable prompt formats

📦 Installation

``bash
npm install fml-sdk
`

Syntax

$3

FML uses angle-bracketed XML-style tags:

| Tag | Purpose |
| ---------------------- | -------------------------- |
| | Imports other .fml files |

`xml

You are a helpful assistant.



Hello, what can you do?



I can help with a variety of tasks including answering questions and writing code.

`

$3

Use {{ variable_name }} syntax for dynamic substitution:

`
Tell me a story about {{ animal }} who learns to {{ skill }}.
`

$3

Modularize prompts using :

`xml

Hello there!
`

Example

`ts
import { parseFML } from 'fml-sdk';

const message = await parseFML('onboarding-prompt.fml', {
name: 'David'
});
`

File Format

- Extension: .fml`
- UTF-8 encoding

Built with AI and ❤️ by David Pichsenmeister to make prompting a bit more human.