The Crochet System

Warning

Crochet is still in development, and its current form is very experimental. Likewise, this book mostly reflects the current form of Crochet, and might change frequently, without much previous notice or support.

You should not be writing anything serious in Crochet yet.

Crochet is a tool designed for creating and remixing interactive media safely. In this book we’ll see what this system is, how it’s structured, and how exactly it allows “creating interactive media safely”.

• What’s Crochet?
  • What is a programming system?
  • How is Crochet safe?
  • What can I do with Crochet?
  • What can I not do with Crochet?
• Installing Crochet
  • (Advanced) Installing Crochet with npm
  • Editor support
• How is Crochet structured?
  • The Crochet universe
  • Package configuration
• Data and types
  • Types and data modelling
  • Hierarchies of types
  • Traits
• Commands
  • What are commands?
  • Signatures and their uses
  • Executing commands
  • Why are commands …?
• Computing with Crochet
  • Execution models
  • Naming values
  • Intrinsic data types
  • Applying programs and commands
  • Using data
  • Equality
  • Branching
  • Working with multiple values
• Effects
  • What are effects?
  • Effect handlers
  • Contextual handlers
• Verification
  • Example-based testing
  • Contracts
• Foreign interfaces
  • Writing external functions
  • The FFI type
• Security and capabilities
  • Why use capabilities?
  • Capabilities and groups
  • Dynamic capabilities
• Annex A: Design philosophy
  • Design principles
  • Language domains
• Annex B: Sociology and linguistics
  • Etymology of Crochet
  • Lexical restrictions of names