# L4 Concepts

Understanding-oriented explanations of the principles, theories, and design decisions behind L4.

## Purpose

Concepts documentation helps you understand:

- **Why** L4 works the way it does
- **How** different features relate to each other
- **When** to use particular patterns or approaches
- **What** theoretical foundations support L4's design

Unlike reference docs (which tell you **what** things are) or tutorials (which show you **how** to do things), concepts explain the **why** and provide deeper understanding.

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## Topics

### 🎨 Language Design

The philosophy and principles behind L4's design

- **[Principles](/l4/concepts/language-design/principles.md)** - Core design principles of L4
- **[Linguistic Syntax](/l4/concepts/language-design/linguistic-syntax.md)** - How L4 borrows from natural language linguistics

**Key Ideas:** Human-readable code, legal text fidelity, accessibility for non-programmers

_More topics planned: Layout Sensitivity, Scope_

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### ⚖️ Legal Modeling

Representing legal concepts in code

- **[Regulative Rules](/l4/concepts/legal-modeling/regulative-rules.md)** - Obligations, permissions, prohibitions

**Key Ideas:** Deontic modalities, legal rules as code, contract patterns

_More topics planned: Deontic Logic, Contract Composition, Constitutive vs Regulative_

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### 🏗️ Type System

How L4's type system works

- **[Algebraic Types](/l4/concepts/type-system/algebraic-types.md)** - Sum types and product types

**Key Ideas:** Type safety, algebraic data types, functional programming influence

_More topics planned: Maybe and Nothing, Type Inference_

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## How to Use Concepts

### During Learning

- Read concept docs **after** you've tried the feature in practice
- Concepts build on knowledge from [courses](/l4/courses.md) and [tutorials](/l4/tutorials.md)

### For Deeper Understanding

- Concepts explain the "why" behind language features
- Use concepts to inform design decisions in your L4 programs

### For Discussion

- Concepts provide vocabulary for discussing L4 design
- Reference concepts when proposing changes or new features

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## Further Reading

### Academic Papers

- Coming soon: Links to papers on L4's theoretical foundations