Anon feature (#412)

* Add anon flag to cli

* Implement anonymisation for accounts

* document the --anon option

doc/lib.m4

@@ -147,6 +147,9 @@ m4_define({{_reportingoptions_}}, {{
 : will transform the journal before any other processing by replacing the account name of every posting having the tag TAG with content VALUE by the  account name "TAG:VALUE".
 : The TAG will only match if it is a full-length match. The pivot will only happen if the TAG is on a posting, not if it is on the transaction. If the tag value is a multi:level:account:name the new account name will be "TAG:multi:level:account:name".
 
+`--anon`
+: show anonymized accounts and payees
+
 }} )m4_dnl
 m4_dnl
 m4_define({{_hledgerdescription_}}, {{

hledger/Hledger/Cli/CliOptions.hs

@@ -143,6 +143,7 @@ reportflags = [
  ,flagReq  ["depth"]         (\s opts -> Right $ setopt "depth" s opts) "N" "hide accounts/postings deeper than N"
  ,flagNone ["empty","E"]     (setboolopt "empty") "show items with zero amount, normally hidden"
  ,flagNone ["cost","B"]      (setboolopt "cost") "show amounts in their cost price's commodity"
+ ,flagNone ["anon"]              (setboolopt "anon") "output ledger with anonymized accounts and payees."
  ]
 
 -- | Common output-related flags: --output-file, --output-format...

hledger/Hledger/Cli/Utils.hs

@@ -23,12 +23,15 @@ module Hledger.Cli.Utils
     )
 where
 import Control.Exception as C
+import Data.Hashable (hash)
 import Data.List
 import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.IO as T
 import Data.Time (Day)
+import Data.Word
+import Numeric
 import Safe (readMay)
 import System.Console.CmdArgs
 import System.Directory (getModificationTime, getDirectoryContents, copyFile)
@@ -73,7 +76,7 @@ withJournalDo opts cmd = do
   rulespath <- rulesFilePathFromOpts opts
   journalpaths <- journalFilePathFromOpts opts
   ej <- readJournalFiles Nothing rulespath (not $ ignore_assertions_ opts) journalpaths
-  either error' (cmd opts . pivotByOpts opts . journalApplyAliases (aliasesFromOpts opts)) ej
+  either error' (cmd opts . pivotByOpts opts . anonymiseByOpts opts . journalApplyAliases (aliasesFromOpts opts)) ej
 
 -- | Apply the pivot transformation on a journal, if option is present.
 pivotByOpts :: CliOpts -> Journal -> Journal
@@ -92,6 +95,30 @@ pivot tag j = j{jtxns = map pivotTrans . jtxns $ j}
     | _                <- tagTuple = p
    where tagTuple = find ((tag ==) . fst) . ptags $ p
 
+-- | Apply the anonymisation transformation on a journal, if option is present
+anonymiseByOpts :: CliOpts -> Journal -> Journal
+anonymiseByOpts opts =
+  case maybestringopt "anon" . rawopts_ $ opts of
+    Just _  -> anonymise
+    Nothing -> id
+
+-- | Apply the anonymisation transformation on a journal
+anonymise :: Journal -> Journal
+anonymise j
+  = let
+      pAnons p = p { paccount = T.intercalate (T.pack ":") . map anon . T.splitOn (T.pack ":") . paccount $ p
+                   , pcomment = T.empty
+                   , ptransaction = fmap tAnons . ptransaction $ p
+                   }
+      tAnons txn = txn { tpostings = map pAnons . tpostings $ txn
+                       , tdescription = anon . tdescription $ txn
+                       , tcomment = T.empty
+                       }
+    in
+      j { jtxns = map tAnons . jtxns $ j }
+  where
+    anon = T.pack . flip showHex "" . (fromIntegral :: Int -> Word32) . hash
+
 -- | Write some output to stdout or to a file selected by --output-file.
 writeOutput :: CliOpts -> String -> IO ()
 writeOutput opts s = do

hledger/hledger.cabal

@@ -98,6 +98,7 @@ library
     , cmdargs >=0.10 && <0.11
     , csv
     , data-default >=0.5
+    , hashable >=1.2.4
     , haskeline >=0.6 && <=0.8
     , HUnit
     , mtl

hledger/package.yaml

@@ -111,6 +111,7 @@ library:
   - cmdargs >=0.10 && <0.11
   - csv
   - data-default >=0.5
+  - hashable >=1.2.4
   - haskeline >=0.6 && <=0.8
   - HUnit
   - mtl