cmp/internal/diff/diff.go
func (es EditScript) String() string {
	b := make([]byte, len(es))
	for i, e := range es {
		switch e {
		case Identity:
			b[i] = '.'
		case UniqueX:
			b[i] = 'X'
		case UniqueY:
			b[i] = 'Y'
		case Modified:
			b[i] = 'M'
		default:
			panic("invalid edit-type")
		}
	}
	return string(b)
}
func (es EditScript) String() string {
	b := make([]byte, len(es))
	for i, e := range es {
		switch e {
		case Identity:
			b[i] = '.'
		case UniqueX:
			b[i] = 'X'
		case UniqueY:
			b[i] = 'Y'
		case Modified:
			b[i] = 'M'
		default:
			panic("invalid edit-type")
		}
	}
	return string(b)
}
// String returns a human-readable string representing the edit-script where
// Identity, UniqueX, UniqueY, and Modified are represented by the
// '.', 'X', 'Y', and 'M' characters, respectively.