Commands

If Types provide the structure for data that a Crochet program manipulates—or “what data looks like”—, then Commands describe how they behave. Commands are one of central concepts of Crochet, and in this section we’ll dive deep into what they are, how they work, and other things you should keep in mind when using them.

• What are commands?
  • Commands are global
  • Signatures
  • Behaviours
• Signatures and their uses
  • Command names
  • Binary command names
    • Change operators
    • Boolean operators
    • Equality operators
    • Relational operators
    • Arithmetic operators
    • Concatenation operators
  • Requirements
    • Multiple trait requirements
    • Convenience forms
    • A word of caution: ambiguity
    • Irrelevant variables
• Executing commands
  • Selection and application
  • The selection algorithm
    • Ranking trait requirements
    • Selection with multiple requirements
    • Ambiguities in selection
    • What if no command is selected?
  • Applying commands
    • The self name
• Why are commands …?
  • Why do we need this “dispatch” thing?
    • Dispatch and security
    • Dispatch and collaboration
  • Why are commands global?
    • How are global commands consistent?
    • How are global commands coherent?