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

declare const spans: (spans: Iterable<Span>) => Span

declare const code: (value: string | Span) => Span

declare const empty: Span

declare const error: (value: string | Span) => Span

declare const space: Span

declare const strong: (value: string | Span) => Span

declare const text: (value: string) => Span

declare const uri: (value: string) => Span

declare const weak: (value: string | Span) => Span

export interface Highlight {
  readonly _tag: "Highlight"
  readonly value: Span
  readonly color: Color
}

export interface Sequence {
  readonly _tag: "Sequence"
  readonly left: Span
  readonly right: Span
}

type Span = Highlight | Sequence | Strong | Text | URI | Weak

export interface Strong {
  readonly _tag: "Strong"
  readonly value: Span
}

export interface Text {
  readonly _tag: "Text"
  readonly value: string
}

export interface URI {
  readonly _tag: "URI"
  readonly value: string
}

export interface Weak {
  readonly _tag: "Weak"
  readonly value: Span
}

declare const isSequence: (self: Span) => self is Sequence

declare const isStrong: (self: Span) => self is Strong

declare const isText: (self: Span) => self is Text

declare const isUri: (self: Span) => self is URI

declare const isWeak: (self: Span) => self is Weak