cli: --auto adds automated postings to reports

Ledger-style automated postings, previously supported only by
hledger-budget, have landed as a first-class feature.  The --auto
flag activates them, so that any postings they generate are
included in reports.

hledger-lib/Hledger/Reports/ReportOptions.hs

@@ -105,6 +105,7 @@ data ReportOpts = ReportOpts {
       -- how to sort negative numbers.
     ,color_          :: Bool
     ,forecast_       :: Bool
+    ,auto_           :: Bool
  } deriving (Show, Data, Typeable)
 
 instance Default ReportOpts where def = defreportopts
@@ -136,6 +137,7 @@ defreportopts = ReportOpts
     def
     def
     def
+    def
 
 rawOptsToReportOpts :: RawOpts -> IO ReportOpts
 rawOptsToReportOpts rawopts = checkReportOpts <$> do
@@ -167,6 +169,7 @@ rawOptsToReportOpts rawopts = checkReportOpts <$> do
     ,pretty_tables_ = boolopt "pretty-tables" rawopts'
     ,color_       = color
     ,forecast_    = boolopt "forecast" rawopts'
+    ,auto_        = boolopt "auto" rawopts'
     }
 
 -- | Do extra validation of raw option values, raising an error if there's a problem.

hledger/Hledger/Cli/CliOptions.hs

@@ -155,7 +155,8 @@ reportflags = [
  ,flagNone ["empty","E"]     (setboolopt "empty") "show items with zero amount, normally hidden"
  ,flagNone ["cost","B"]      (setboolopt "cost") "convert amounts to their cost at transaction time (using the transaction price, if any)"
  ,flagNone ["value","V"]     (setboolopt "value") "convert amounts to their market value on the report end date (using the most recent applicable market price, if any)"
- ,flagNone ["forecast"] (\opts -> setboolopt "forecast" opts) "generate forecast transactions"
+ ,flagNone ["forecast"]      (setboolopt "forecast") "generate forecast transactions"
+ ,flagNone ["auto"]          (setboolopt "auto") "generate automated postings"
  ]
 
 -- | Common output-related flags: --output-file, --output-format...

hledger/Hledger/Cli/Utils.hs

@@ -54,6 +54,7 @@ import Hledger.Data
 import Hledger.Read
 import Hledger.Reports
 import Hledger.Utils
+import Hledger.Query (Query(Any))
 
 
 -- | Parse the user's specified journal file, maybe apply some transformations
@@ -71,6 +72,7 @@ withJournalDo opts cmd = do
           . journalApplyAliases (aliasesFromOpts opts)
         <=< journalApplyValue (reportopts_ opts)
         <=< journalAddForecast opts
+          . generateAutomaticPostings (reportopts_ opts)
   either error' f ej
 
 -- | Apply the pivot transformation on a journal, if option is present.
@@ -141,6 +143,15 @@ journalAddForecast opts j = do
       in
        either error' id $ journalBalanceTransactions assrt j
 
+-- | Generate Automatic postings and add them to the current journal.
+generateAutomaticPostings :: ReportOpts -> Journal -> Journal
+generateAutomaticPostings ropts j = 
+  if auto_ ropts then j { jtxns = map modifier $ jtxns j } else j
+  where
+    modifier = foldr (flip (.) . runModifierTransaction') id mtxns
+    runModifierTransaction' = fmap txnTieKnot . runModifierTransaction Any
+    mtxns = jmodifiertxns j
+
 -- | Write some output to stdout or to a file selected by --output-file.
 -- If the file exists it will be overwritten.
 writeOutput :: CliOpts -> String -> IO ()

tests/budget/auto.test

@@ -0,0 +1,78 @@
+# Add proportional income tax (from documentation)
+hledger print -f- --auto
+<<<
+2016/1/1 paycheck
+    income:remuneration     $-100
+    income:donations         $-15
+    assets:bank
+
+2016/1/1 withdraw
+    assets:cash             $20
+    assets:bank
+
+= ^income
+  (liabilities:tax)  *.33  ; income tax
+>>>
+2016/01/01 paycheck
+    income:remuneration           $-100
+    income:donations               $-15
+    assets:bank
+    (liabilities:tax)              $-33    ; income tax
+    (liabilities:tax)               $-5    ; income tax
+
+2016/01/01 withdraw
+    assets:cash             $20
+    assets:bank
+
+>>>2
+>>>=0
+
+hledger register -f- --auto
+<<<
+2016/1/1 paycheck
+    income:remuneration     $-100
+    income:donations         $-15
+    assets:bank
+
+2016/1/1 withdraw
+    assets:cash             $20
+    assets:bank
+
+= ^income
+  (liabilities:tax)  *.33  ; income tax
+>>>
+2016/01/01 paycheck             income:remuneration          $-100         $-100
+                                income:donations              $-15         $-115
+                                assets:bank                   $115             0
+                                (liabilities:tax)             $-33          $-33
+                                (liabilities:tax)              $-5          $-38
+2016/01/01 withdraw             assets:cash                    $20          $-18
+                                assets:bank                   $-20          $-38
+>>>2
+>>>=0
+
+hledger balance -f- --auto
+<<<
+2016/1/1 paycheck
+    income:remuneration     $-100
+    income:donations         $-15
+    assets:bank
+
+2016/1/1 withdraw
+    assets:cash             $20
+    assets:bank
+
+= ^income
+  (liabilities:tax)  *.33  ; income tax
+>>>
+                $115  assets
+                 $95    bank
+                 $20    cash
+               $-115  income
+                $-15    donations
+               $-100    remuneration
+                $-38  liabilities:tax
+--------------------
+                $-38
+>>>2
+>>>=0