lib: refactor, txnTieKnot automatically

hledger-lib/Hledger/Data/TransactionModifier.hs

@@ -21,6 +21,7 @@ import Data.Time.Calendar
 import Hledger.Data.Types
 import Hledger.Data.Dates
 import Hledger.Data.Amount
+import Hledger.Data.Transaction
 import Hledger.Query
 import Hledger.Utils.UTF8IOCompat (error')
 -- import Hledger.Utils.Debug
@@ -32,10 +33,12 @@ import Hledger.Utils.UTF8IOCompat (error')
 -- >>> import Hledger.Data.Journal
 
 -- | Converts a 'TransactionModifier' and a 'Query' to a 
--- 'Transaction'-transforming function. The query allows injection of
--- additional restrictions on which postings to modify. 
--- The transformer function will not call 'txnTieKnot', you will
--- probably want to call that after using it.
+-- 'Transaction'-transforming function, which applies the modification(s)
+-- specified by the TransactionModifier. Currently this means adding automated
+-- postings when certain other postings - specified by the TransactionModifier,
+-- and additionally limited by the extra query, if it's not 'Any' - are present.
+-- The postings of the transformed transaction will reference it, as usual 
+-- ('txnTieKnot').
 --
 -- >>> transactionModifierToFunction Any (TransactionModifier "" ["pong" `post` usd 2]) nulltransaction{tpostings=["ping" `post` usd 1]}
 -- 0000/01/01
@@ -61,7 +64,7 @@ import Hledger.Utils.UTF8IOCompat (error')
 -- <BLANKLINE>
 transactionModifierToFunction :: Query -> TransactionModifier -> (Transaction -> Transaction)
 transactionModifierToFunction q mt = 
-  \t@(tpostings -> ps) -> t { tpostings = generatePostings ps } -- TODO add modifier txn comment/tags ?
+  \t@(tpostings -> ps) -> txnTieKnot t{ tpostings=generatePostings ps } -- TODO add modifier txn comment/tags ?
   where
     q' = simplifyQuery $ And [q, tmParseQuery mt (error' "a transaction modifier's query cannot depend on current date")]
     mods = map tmPostingToFunction $ tmpostings mt

hledger-lib/Hledger/Read/Common.hs

@@ -206,11 +206,10 @@ journalSourcePos p p' = JournalSourcePos (sourceName p) (fromIntegral . unPos $
 
 -- | Generate Automatic postings and add them to the current journal.
 generateAutomaticPostings :: Journal -> Journal
-generateAutomaticPostings j = j { jtxns = map modifier $ jtxns j }
+generateAutomaticPostings j = j { jtxns = map applyallmodifiers $ jtxns j }
   where
-    modifier = foldr (flip (.) . transactionModifierToFunction') id mtxns
-    transactionModifierToFunction' = fmap txnTieKnot . transactionModifierToFunction Q.Any
-    mtxns = jtxnmodifiers j
+    applyallmodifiers = 
+      foldr (flip (.) . transactionModifierToFunction Q.Any) id (jtxnmodifiers j)
 
 -- | Given a megaparsec ParsedJournal parser, input options, file
 -- path and file content: parse and post-process a Journal, or give an error.

hledger/Hledger/Cli/Commands/Rewrite.hs

@@ -181,11 +181,9 @@ rewrite opts@CliOpts{rawopts_=rawopts,reportopts_=ropts} j@Journal{jtxns=ts} = d
   modifier <- transactionModifierFromOpts rawopts
   -- create re-writer
   let modifiers = modifier : jtxnmodifiers j
-      -- Note that some query matches require transaction. Thus modifiers
-      -- pipeline should include txnTieKnot on every step.
-      modifier' = foldr (flip (.) . fmap txnTieKnot . transactionModifierToFunction q) id modifiers
+      applyallmodifiers = foldr (flip (.) . transactionModifierToFunction q) id modifiers
   -- rewrite matched transactions
-  let j' = j{jtxns=map modifier' ts}
+  let j' = j{jtxns=map applyallmodifiers ts}
   -- run the print command, showing all transactions
   outputFromOpts rawopts opts{reportopts_=ropts{query_=""}} j j'