declare const alternation: { (that: Usage): (self: Usage) => Usage; (self: Usage, that: Usage): Usage }

declare const concat: { (that: Usage): (self: Usage) => Usage; (self: Usage, that: Usage): Usage }

declare const getHelp: (self: Usage) => HelpDoc

declare const optional: (self: Usage) => Usage

declare const repeated: (self: Usage) => Usage

declare const empty: Usage

declare const enumerate: {
  (config: CliConfig): (self: Usage) => Array<Span>
  (self: Usage, config: CliConfig): Array<Span>
}

declare const mixed: Usage

declare const named: (names: ReadonlyArray<string>, acceptedValues: Option<string>) => Usage

export interface Alternation {
  readonly _tag: "Alternation"
  readonly left: Usage
  readonly right: Usage
}

export interface Concat {
  readonly _tag: "Concat"
  readonly left: Usage
  readonly right: Usage
}

export interface Empty {
  readonly _tag: "Empty"
}

export interface Mixed {
  readonly _tag: "Mixed"
}

export interface Named {
  readonly _tag: "Named"
  readonly names: ReadonlyArray<string>
  readonly acceptedValues: Option<string>
}

export interface Optional {
  readonly _tag: "Optional"
  readonly usage: Usage
}

export interface Repeated {
  readonly _tag: "Repeated"
  readonly usage: Usage
}

type Usage = Empty | Mixed | Named | Optional | Repeated | Alternation | Concat