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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 as TL
import qualified Data.Text.Lazy.Builder as TB import qualified Data.Text.Lazy.Builder as TB
import System.Console.CmdArgs.Explicit (flagNone, flagReq) import System.Console.CmdArgs.Explicit (flagNone, flagReq)
import Safe (maximumDef)
import Hledger import Hledger
import Hledger.Read.CsvReader (CSV, CsvRecord, printCSV) 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. -- | Render a register report as plain text suitable for console output.
postingsReportAsText :: CliOpts -> PostingsReport -> TL.Text postingsReportAsText :: CliOpts -> PostingsReport -> TL.Text
postingsReportAsText opts items = TB.toLazyText $ foldMap first3 linesWithWidths postingsReportAsText opts items = TB.toLazyText lines
where where
linesWithWidths = map (postingsReportItemAsText opts amtwidth balwidth) items lines = foldMap (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
amtwidth = maximumStrict $ 12 : widths (map itemamt items) amtwidth = maximumStrict $ 12 : widths (map itemamt items)
balwidth = maximumStrict $ 12 : widths (map itembal 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) widths = map wbWidth . concatMap (showMixedAmountLinesB oneLine)
itemamt (_,_,_,Posting{pamount=a},_) = a itemamt (_,_,_,Posting{pamount=a},_) = a
itembal (_,_,_,_,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 -- Also returns the natural width (without padding) of the amount and balance
-- fields. -- 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) = postingsReportItemAsText opts preferredamtwidth preferredbalwidth (mdate, mperiod, mdesc, p, b) =
(table <> TB.singleton '\n', thisamtwidth, thisbalwidth) table <> TB.singleton '\n'
where where
table = renderRowB def{tableBorders=False, borderSpaces=False} . Group NoLine $ map Header table = renderRowB def{tableBorders=False, borderSpaces=False} . Group NoLine $ map Header
[ textCell TopLeft $ fitText (Just datewidth) (Just datewidth) True True date [ textCell TopLeft $ fitText (Just datewidth) (Just datewidth) True True date
@ -187,10 +181,6 @@ postingsReportItemAsText opts preferredamtwidth preferredbalwidth (mdate, mperio
amt = showamt $ pamount p amt = showamt $ pamount p
bal = showamt b bal = showamt b
showamt = showMixedAmountLinesB oneLine{displayColour=color_ . _rsReportOpts $ reportspec_ opts} 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 -- tests