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cln: register: Remove unused knot-tying code.

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The conclusion is that trying to tie that knot will inevitably lead to
linear memory consumption; any solution which avoids this, if it exists,
will need significantly different code.

cf. https://stackoverflow.com/questions/66563595/can-i-exploit-lazy-evaluation-to-reference-future-values-without-space-leaks
This commit is contained in:
Stephen Morgan 2021-08-23 10:19:53 +10:00 committed by Simon Michael
parent 59b89947eb
commit 90fd2a9aaf
1 changed files with 4 additions and 14 deletions
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18
hledger/Hledger/Cli/Commands/Register.hs
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@ -24,7 +24,6 @@ import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Builder as TB
import System.Console.CmdArgs.Explicit (flagNone, flagReq)
import Safe (maximumDef)
import Hledger
import Hledger.Read.CsvReader (CSV, CsvRecord, printCSV)
@ -95,16 +94,11 @@ postingsReportItemAsCsvRecord (_, _, _, p, b) = [idx,date,code,desc,acct,amt,bal
-- | Render a register report as plain text suitable for console output.
postingsReportAsText :: CliOpts -> PostingsReport -> TL.Text
postingsReportAsText opts items = TB.toLazyText $ foldMap first3 linesWithWidths
postingsReportAsText opts items = TB.toLazyText lines
where
linesWithWidths = map (postingsReportItemAsText opts amtwidth balwidth) items
-- Tying this knot seems like it will save work, but ends up creating a big
-- space leak. Can we fix that leak without recalculating everything?
-- amtwidth = maximum $ 12 : map second3 linesWithWidths
-- balwidth = maximum $ 12 : map third3 linesWithWidths
lines = foldMap (postingsReportItemAsText opts amtwidth balwidth) items
amtwidth = maximumStrict $ 12 : widths (map itemamt items)
balwidth = maximumStrict $ 12 : widths (map itembal items)
-- Since postingsReport strips prices from all Amounts when not used, we can display prices.
widths = map wbWidth . concatMap (showMixedAmountLinesB oneLine)
itemamt (_,_,_,Posting{pamount=a},_) = a
itembal (_,_,_,_,a) = a
@ -133,9 +127,9 @@ postingsReportAsText opts items = TB.toLazyText $ foldMap first3 linesWithWidths
--
-- Also returns the natural width (without padding) of the amount and balance
-- fields.
postingsReportItemAsText :: CliOpts -> Int -> Int -> PostingsReportItem -> (TB.Builder, Int, Int)
postingsReportItemAsText :: CliOpts -> Int -> Int -> PostingsReportItem -> TB.Builder
postingsReportItemAsText opts preferredamtwidth preferredbalwidth (mdate, mperiod, mdesc, p, b) =
(table <> TB.singleton '\n', thisamtwidth, thisbalwidth)
table <> TB.singleton '\n'
where
table = renderRowB def{tableBorders=False, borderSpaces=False} . Group NoLine $ map Header
[ textCell TopLeft $ fitText (Just datewidth) (Just datewidth) True True date
@ -187,10 +181,6 @@ postingsReportItemAsText opts preferredamtwidth preferredbalwidth (mdate, mperio
amt = showamt $ pamount p
bal = showamt b
showamt = showMixedAmountLinesB oneLine{displayColour=color_ . _rsReportOpts $ reportspec_ opts}
-- Since this will usually be called with the knot tied between this(amt|bal)width and
-- preferred(amt|bal)width, make sure the former do not depend on the latter to avoid loops.
thisamtwidth = maximumDef 0 $ map wbWidth amt
thisbalwidth = maximumDef 0 $ map wbWidth bal
-- tests