comment-in-operator-chain.hs

{-# LANGUAGE PatternSynonyms #-}

everyOperandAnnotated =
  base -- what we started from
    + delta -- what was added
    - refund -- and what came back

annotatedOperators =
  base
    + -- the adjustment
      delta
    - -- the reimbursement
      refund

remarkBetweenOperatorAndOperand =
  opening
    <> -- said once
      -- and never twice
      closing

lastOperandOnly =
  first
    `mappend` second
    `mappend` third -- and no further

-- An operator written at the end of a line goes to the start of the next,
-- and a comment written after it stays with the operand it follows.
operatorsAtLineEnds = base + -- what we started from
  delta - -- what was added
  refund -- and what came back

-- The same, one level of precedence down.
tighterOperatorAtLineEnd = base + rate * -- per unit
  units

-- The same, for a constructor in a pattern.
headOf (x :| -- the one we want
  _) = x

-- The same, for a pattern synonym.
pattern x :< -- the head
  xs = (x, xs)

-- A comment written on a line of its own between such an operator and its
-- operand comes before the operator.
remarkUnderAnOperatorAtLineEnd = base ++
  -- what is added
  extra