predstrings

var (
	// LastIndexOf returns a function that reports the index of the
	// last occurrence of substr in s (-1 if absent).
	LastIndexOf = F.Bind2of2(strings.LastIndex)

	// HasSuffix returns a function that reports whether s ends with suffix.
	HasSuffix = F.Bind2of2(strings.HasSuffix)

	// ContainsRuneClass returns a function that reports whether s
	// contains any rune satisfying pred.
	ContainsRuneClass = F.Bind2of2(strings.ContainsFunc)

	// HasAtSign returns true when "@" exists anywhere in the string
	// (last index >= 0).
	HasAtSign = F.Pipe2(
		0,
		ORD.Geq(predord.IntOrd),
		Pred.ContraMap(LastIndexOf("@")),
	)
)