dev: lib: drop dead cost-basis-inference helpers

journalInferPostingsCostBasis, postingInferCostBasis, postingUsesLots,
and divideAmountAndCapPrecision were exported (in the case of the first
and last) but had no callers in the pipeline. The two real callers of
divideAmountAndCapPrecision were removed by the recent basis-check
precision work; the journal-side cost-basis inference helpers were never
wired in.

Removing them makes defaultMaxDisplayPrecision genuinely display-only
in all reachable code, matching its name.

Author: simonmichael

hledger-lib/Hledger/Data/Amount.hs

@@ -68,7 +68,6 @@ module Hledger.Data.Amount (
   amountLooksZero,
   amountSetQuantity,
   divideAmount,
-  divideAmountAndCapPrecision,
   multiplyAmount,
   invertAmount,
   -- ** styles
@@ -391,17 +390,6 @@ transformAmount f a@Amount{aquantity=q,acost=p} = a{aquantity=f q, acost=f' <$>
 divideAmount :: Quantity -> Amount -> Amount
 divideAmount n = transformAmount (/n)
 
--- | Divide an amount's quantity by some number, then round both internal and
--- display precision to the quotient's natural precision capped at
--- 'defaultMaxDisplayPrecision'. This avoids non-terminating divisions (eg 53/7)
--- leaving 255 decimal digits of slop in the internal quantity, while still showing
--- every decimal digit a clean division produces.
-divideAmountAndCapPrecision :: Quantity -> Amount -> Amount
-divideAmountAndCapPrecision n a =
-  let a' = a{aquantity = aquantity a / n}
-      p  = min defaultMaxDisplayPrecision (amountInternalPrecision a')
-  in setAmountInternalPrecision p a'
-
 -- | Multiply an amount's quantity (and its total cost, if it has one) by a constant.
 multiplyAmount :: Quantity -> Amount -> Amount
 multiplyAmount n = transformAmount (*n)

hledger-lib/Hledger/Data/Journal.hs

@@ -44,7 +44,6 @@ module Hledger.Data.Journal (
   journalPostingsAddAccountTags,
   journalPostingsKeepAccountTagsOnly,
   journalPostingsAddCommodityTags,
-  journalInferPostingsCostBasis,
   journalInferPostingsTransactedCost,
   journalCommodityUsesLots,
   journalCommodityLotsMethod,
@@ -157,7 +156,7 @@ import Data.List (foldl')
 #endif
 import Data.List.Extra (nubSort)
 import Data.Map.Strict qualified as M
-import Data.Maybe (catMaybes, fromMaybe, isJust, isNothing, mapMaybe, maybeToList)
+import Data.Maybe (catMaybes, fromMaybe, isNothing, mapMaybe, maybeToList)
 import Data.Ord (comparing)
 import Data.Set qualified as S
 import Data.Text (Text)
@@ -716,10 +715,6 @@ journalCommodityTags Journal{jdeclaredcommoditytags} c =
 journalCommodityUsesLots :: Journal -> CommoditySymbol -> Bool
 journalCommodityUsesLots j c = any ((== "lots") . T.toLower . fst) (journalCommodityTags j c)
 
--- | Does this posting have a 'lots:' tag (eg inherited from its account) ?
-postingUsesLots :: Posting -> Bool
-postingUsesLots p = any ((== "lots") . T.toLower . fst) (ptags p)
-
 -- | Get the reduction method from a commodity's lots: tag value, if any.
 journalCommodityLotsMethod :: Journal -> CommoditySymbol -> Maybe ReductionMethod
 journalCommodityLotsMethod j c =
@@ -795,32 +790,6 @@ journalPostingsAddCommodityTags j = journalMapPostings addtags j
   where
     addtags p = p `postingAddTags` concatMap (journalCommodityTags j) (postingCommodities p)
 
--- | For acquire postings (positive amounts) whose commodity or account has a 'lots:' tag,
--- infer cost basis (cost only, no date or label) from transacted cost.
--- The lot date will later default to the transaction date.
--- Must be called before journalClassifyLotPostings.
-journalInferPostingsCostBasis :: Journal -> Journal
-journalInferPostingsCostBasis j = journalMapPostings (postingInferCostBasis j) j
-
-postingInferCostBasis :: Journal -> Posting -> Posting
-postingInferCostBasis j p = p{pamount = mapMixedAmount amountInferCostBasis $ pamount p}
-  where
-    amountInferCostBasis :: Amount -> Amount
-    amountInferCostBasis a
-      | aquantity a <= 0                  = a  -- only positive (acquire) amounts
-      | isJust (acostbasis a)             = a  -- already has cost basis
-      | Nothing <- acost a                = a  -- no transacted cost
-      | not (journalCommodityUsesLots j (acommodity a) || postingUsesLots p) = a  -- commodity/account not lot-tracked
-      | Just cost <- acost a              = a{acostbasis = Just (costToCostBasis (aquantity a) cost)}
-
-    costToCostBasis :: Quantity -> AmountCost -> CostBasis
-    costToCostBasis qty cost = CostBasis{cbCost=Just ucost, cbDate=Nothing, cbLabel=Nothing}
-      where
-        ucost = case cost of
-          UnitCost  amt              -> amt
-          TotalCost amt | qty /= 0   -> divideAmountAndCapPrecision (abs qty) amt
-                        | otherwise  -> amt
-
 -- | For positive postings with a cost basis, which are not lot transfers,
 -- infer transacted cost from cost basis.
 -- Must be called after journalClassifyLotPostings so ptype tags are available.