ruleAUnitofduration :: Rule
ruleAUnitofduration = Rule
  { name = "a <unit-of-duration>"
  , pattern =
    [ regex "en|ett?"
    , dimension TimeGrain
    ]
  , prod = \tokens -> case tokens of
      (_:Token TimeGrain grain:_) ->
        Just . Token Duration $ duration grain 1
      _ -> Nothing
  }
ruleAUnitofduration :: Rule
ruleAUnitofduration = Rule
  { name = "a <unit-of-duration>"
  , pattern =
    [ regex "en|ett?"
    , dimension TimeGrain
    ]
  , prod = \tokens -> case tokens of
      (_:Token TimeGrain grain:_) ->
        Just . Token Duration $ duration grain 1
      _ -> Nothing
  }
ruleAUnitofduration = Rule
  { name = "a <unit-of-duration>"
  , pattern =
    [ regex "en|ett?"
    , dimension TimeGrain
    ]
  , prod = \tokens -> case tokens of
      (_:Token TimeGrain grain:_) ->
        Just . Token Duration $ duration grain 1
      _ -> Nothing
  }