diff --git a/Hledger/Interest.hs b/Hledger/Interest.hs --- a/Hledger/Interest.hs +++ b/Hledger/Interest.hs @@ -48,9 +48,8 @@ interestAcc <- asks interestAccount let posts = [ p | p <- tpostings ts, interestAcc == paccount p ] forM_ posts $ \p -> do - bal <- gets (amounts . balance) - let bal' = bal ++ amounts (pamount p) - modify (\st -> st { balance = normaliseMixedAmount (Mixed bal') }) + bal <- gets (balance) + modify (\st -> st { balance = normaliseMixedAmount (bal + (pamount p)) }) computeInterest :: Day -> Computer () computeInterest day = do diff --git a/Main.hs b/Main.hs --- a/Main.hs +++ b/Main.hs @@ -29,7 +29,7 @@ { optVerbose = True , optShowVersion = False , optShowHelp = False - , optInput = "" + , optInput = "-" , optSourceAcc = "" , optTargetAcc = "" , optDCC = Nothing @@ -43,8 +43,8 @@ , Option ['V'] ["version"] (NoArg (\o -> o { optShowVersion = True })) "show version number and exit" , Option ['v'] ["verbose"] (NoArg (\o -> o { optVerbose = True })) "echo input ledger to stdout (default)" , Option ['q'] ["quiet"] (NoArg (\o -> o { optVerbose = False })) "don't echo input ledger to stdout" - , Option [] ["today"] (NoArg (\o -> o { optBalanceToday = True })) "update account until today" - , Option ['f'] ["file"] (ReqArg (\f o -> o { optInput = f }) "FILE") "input ledger file" + , Option [] ["today"] (NoArg (\o -> o { optBalanceToday = True })) "compute interest up until today" + , Option ['f'] ["file"] (ReqArg (\f o -> o { optInput = f }) "FILE") "input ledger file (pass '-' for stdin)" , Option ['s'] ["source"] (ReqArg (\a o -> o { optSourceAcc = a }) "ACCOUNT") "interest source account" , Option ['t'] ["target"] (ReqArg (\a o -> o { optTargetAcc = a }) "ACCOUNT") "interest target account" , Option [] ["act"] (NoArg (\o -> o { optDCC = Just diffAct })) "use 'act' day counting convention" @@ -75,16 +75,19 @@ (opts, args) <- getArgs >>= parseOpts when (optShowVersion opts) (putStrLn (display version) >> exitSuccess) when (optShowHelp opts) (putStr usageMessage >> exitSuccess) - when (null (optInput opts)) (commandLineError "required --file option is missing\n") when (null (optSourceAcc opts)) (commandLineError "required --source option is missing\n") when (null (optTargetAcc opts)) (commandLineError "required --target option is missing\n") when (isNothing (optDCC opts)) (commandLineError "no day counting convention specified\n") when (isNothing (optRate opts)) (commandLineError "no interest rate specified\n") - when (length args /= 1) (commandLineError "required argument ACCOUNT is missing\n") + when (length args < 1) (commandLineError "required argument ACCOUNT is missing\n") + when (length args > 1) (commandLineError "only one interest ACCOUNT may be specified\n") + input <- case optInput opts of + "-" -> getContents + file -> readFile file + jnl' <- readJournal Nothing input >>= either fail return let [interestAcc] = args - Right jnl' <- readFile (optInput opts) >>= readJournal Nothing - let jnl = filterJournalTransactionsByAccount [interestAcc] jnl' - ts = sortBy (comparing tdate) (jtxns jnl) + jnl = filterJournalTransactionsByAccount [interestAcc] jnl' + ts = sortBy (comparing tdate) (jtxns jnl) cfg = Config { interestAccount = interestAcc , sourceAccount = optSourceAcc opts @@ -98,6 +101,6 @@ | otherwise = return () ts' = runComputer cfg (mapM_ processTransaction ts >> finalize) result - | optVerbose opts = ts ++ ts' + | optVerbose opts = ts' ++ ts | otherwise = ts' mapM_ (putStr . show) (sortBy (comparing tdate) result) diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,184 @@ +hledger-interest +================ + +hledger-interest is a small command-line utility based on [Simon +Michael's hleder library](http://hledger.org/). Its purpose is to +compute interest for a given ledger account. Using command line flags, +the program can be configured to use various [day counting +conventions](http://en.wikipedia.org/wiki/Day_count_convention), such as +"act/act", "30/360", "30E/360", and "30/360isda". Furthermore, it +supports several of different interest schemes, i.e. annual interest +with a fixed rate and the scheme mandated by the German law [§ 288 BGB +Verzugszinsen](http://de.wikipedia.org/wiki/Verzugszinssatz). Extending +support for other schemes is fairly easy, but currently requires hacking +the source code. + +An overview over the available run-time options can be displayed by +running "`hleder-interest --help`": + + Usage: hledger-interest [OPTION...] ACCOUNT + -v --verbose echo input ledger to stdout (default) + -q --quiet don't echo input ledger to stdout + --today compute interest up until today + -f FILE --file=FILE input ledger file (pass '-' for stdin) + -s ACCOUNT --source=ACCOUNT interest source account + -t ACCOUNT --target=ACCOUNT interest target account + --act use 'act' day counting convention + --30-360 use '30/360' day counting convention + --30E-360 use '30E/360' day counting convention + --30E-360isda use '30E/360isda' day counting convention + --constant=RATE constant interest rate + --annual=RATE annual interest rate + --bgb288 compute interest according to German BGB288 + +When run, hledger-interest reads the [ledger +file](http://hledger.org/MANUAL.html#file-format) designated by the +`--file` flag and filters all transactions that change the account +specified on the command line. All other accounts will be ignored. Every +time a transaction modifies the given account's balance -- thereby +changing the amount of money that earns interest --, hledger-interest +transfers the interest that accrued so far. Interest will be debited +from the account designed by the `--source` flag and credited to the +account designed by the `--target` flag. + +## Examples + +Suppose that you've loaned 1000 Euro from your bank at an annual +interest rate of 5%, and that you would like to see how interest +develops over time. Then you would create a ledger file, say +`loan.ledger`, that looks something like this: + + 2010/09/26 Loan + Assets:Bank EUR 1000.00 + Liabilities:Loan + +Now, `ledger-interest` is run to determine the interest up until today: + + $ hledger-interest -f loan.ledger --act --annual=0.05 --today -s Expenses:Interest -t Liabilities:Loan:Interest Liabilities:Loan + 2010/09/26 Loan + Assets:Bank EUR 1000.00 + Liabilities:Loan + + 2010/12/31 5.00% interest for EUR -1000.00 over 96 days + Liabilities:Loan:Interest EUR -13.15 + Expenses:Interest + + 2011/08/22 5.00% interest for EUR -1000.00 over 234 days + Liabilities:Loan:Interest EUR -32.05 + Expenses:Interest + +Note a separate credit account for the interest was chosen: +`Liabilities:Loan:Interest`. Consequently, interest accrued in one +interest period does *not* earn interest in the following periods. If +interest is credited to the main account instead, that behavior changes: + + $ hledger-interest -f loan.ledger --act --annual=0.05 --today -s Expenses:Interest -t Liabilities:Loan Liabilities:Loan + 2010/09/26 Loan + Assets:Bank EUR 1000.00 + Liabilities:Loan + + 2010/12/31 5.00% interest for EUR -1000.00 over 96 days + Liabilities:Loan EUR -13.15 + Expenses:Interest + + 2011/08/22 5.00% interest for EUR -1013.15 over 234 days + Liabilities:Loan EUR -32.48 + Expenses:Interest + +Of course, loans are supposed to be paid back, and these payments change +the amount of interest accrued. Suppose that `load.ledger` would be +extended by the following transactions: + + 2010/12/11 Payment + Assets:Bank EUR -150.00 + Liabilities:Loan + + 2011/03/07 Payment + Assets:Bank EUR -300.00 + Liabilities:Loan + + 2011/08/21 Payment + Assets:Bank EUR -150.00 + Liabilities:Loan + +Then interest would develop as follows: + + $ hledger-interest -f loan.ledger --act --annual=0.05 -s Expenses:Interest -t Liabilities:Loan Liabilities:Loan + 2010/09/26 Loan + Assets:Bank EUR 1000.00 + Liabilities:Loan + + 2010/12/11 5.00% interest for EUR -1000.00 over 76 days + Liabilities:Loan EUR -10.41 + Expenses:Interest + + 2010/12/11 Payment + Assets:Bank EUR -150.00 + Liabilities:Loan + + 2010/12/31 5.00% interest for EUR -860.41 over 20 days + Liabilities:Loan EUR -2.36 + Expenses:Interest + + 2011/03/07 5.00% interest for EUR -862.77 over 66 days + Liabilities:Loan EUR -7.80 + Expenses:Interest + + 2011/03/07 Payment + Assets:Bank EUR -300.00 + Liabilities:Loan + + 2011/08/21 5.00% interest for EUR -570.57 over 167 days + Liabilities:Loan EUR -13.05 + Expenses:Interest + + 2011/08/21 Payment + Assets:Bank EUR -150.00 + Liabilities:Loan + +Last but not least, there is a special case known as "Verzugszinsen" in +German law, which applies when someone is supposed to pay a bill, but +fails to do so on time. For every day past the deadline, interest +accrues according to terms specified in [§ 247 +BGB](http://www.gesetze-im-internet.de/bgb/__247.html). The command line +flag `--bgb288` enables this scheme in `hledger-interest`. + +Let's assume that customer ACME is supposed to pay 35 Euro by +2010/09/15, but the money actually arrives almost half a year late: + + 2010/09/15 Services rendered to Customer ACME + ACME EUR -35.00 ; 1 hour @ EUR 35.00 + Receivable:ACME + + 2011/03/17 ACME + ACME EUR 35.00 + Receivable:ACME + +According to German law, you are entitled to the following interest: + + $ hledger-interest -f acme.ledger --quiet --bgb288 -s Income:Interest -t Receivable:ACME:Interest Receivable:ACME + 2010/12/31 5.12% interest for EUR 35.00 over 107 days + Receivable:ACME:Interest EUR 0.53 + Income:Interest + + 2011/03/17 5.12% interest for EUR 35.00 over 76 days + Receivable:ACME:Interest EUR 0.37 + Income:Interest + +So, if you're smart, then you'll book the payment so that the accrued +interest is paid *first*: + + 2011/03/17 ACME + ACME EUR 35.00 + Receivable:ACME:Interest EUR -0.90 + Receivable:ACME + +This gives the following transaction history for the ACME account: + + $ hledger-interest -f acme.ledger --bgb288 -s Income:Interest -t Receivable:ACME:Interest Receivable:ACME | + hledger -f - reg Receivable:ACME + 2010/09/15 Services rendered .. Receivable:ACME EUR 35.00 EUR 35.00 + 2010/12/31 5.12% interest for.. Re:ACME:Interest EUR 0.53 EUR 35.53 + 2011/03/17 5.12% interest for.. Re:ACME:Interest EUR 0.37 EUR 35.90 + 2011/03/17 ACME Re:ACME:Interest EUR -0.90 EUR 35.00 + Receivable:ACME EUR -34.10 EUR 0.90 diff --git a/hledger-interest.cabal b/hledger-interest.cabal --- a/hledger-interest.cabal +++ b/hledger-interest.cabal @@ -1,5 +1,5 @@ Name: hledger-interest -Version: 1.1 +Version: 1.2 Synopsis: computes interest for a given account License: BSD3 License-file: LICENSE @@ -9,17 +9,18 @@ Category: Finance Build-type: Simple Cabal-version: >= 1.6 -Tested-With: GHC == 6.12.3, GHC == 7.0.4, GHC == 7.2.1 +Tested-with: GHC == 6.12.3, GHC == 7.0.4, GHC == 7.2.1 +Data-files: README.md Description: hledger-interest is a small command-line utility based on Simon Michael's hleder library. Its purpose is to compute interest for a given ledger account. Using command line flags, the program can be - configured to use various schemes for day-counting, such as act/act, - 30/360, 30E/360, and 30/360isda. Furthermore, it supports a (small) + configured to use various schemes for day-counting, such as act\/act, + 30\/360, 30E\/360, and 30\/360isda. Furthermore, it supports a (small) number of interest schemes, i.e. annual interest with a fixed rate and the scheme mandated by the German BGB288 (Basiszins für Verbrauchergeschäfte). Extending support for other schemes is fairly - easy, but currently requires changing to the source code. + easy, but currently requires changes to the source code. . As an example, consider the following loan, stored in a file called @test.ledger@: @@ -111,7 +112,7 @@ Executable hledger-interest Main-is: Main.hs - Build-depends: base >= 3 && < 5, hledger-lib >= 0.14, time, mtl, Cabal + Build-depends: base >= 3 && < 5, hledger-lib == 0.14, time, mtl, Cabal other-modules: Hledger.Interest Hledger.Interest.DayCountConvention Hledger.Interest.Rate