--
-- >>> let (Right r) = parse let_dig_hyp "" "-"
-- >>> LdhStrSingleLdh r
--- LdhStrSingleLdh (LetDigHypHyphen (Hyphen '-'))
+-- LdhStrSingleLdh (LetDigHypHyphen Hyphen)
--
-- We can create an 'LdhStrMultipleLdh' from multiple (let-dig-hyp)
-- characters:
-- LdhStrSingleLdh (LetDigHypLetDig (LetDigDigit (Digit '0')))
--
-- >>> parseTest ldh_str "-"
--- LdhStrSingleLdh (LetDigHypHyphen (Hyphen '-'))
+-- LdhStrSingleLdh (LetDigHypHyphen Hyphen)
--
-- As well as strings of them:
--