Module names 

The naming rules a command line forces on a document: where an operation sits in the two-level command tree, and what happens when two things in one operation want the same flag.

Structs

CommandName

One half of a command name: kebab-cased, [a-z0-9-] only.

Grouping

Where each of a document’s operations sits in the command tree.

NameError

A name the document offers that is not spellable as a command.

Namespace

The flag names one subcommand has already spent.

Functions

kebab

createVoucher and internal_ref both become flag-shaped: lowercase words joined by -. Characters outside [A-Za-z0-9] are separators.