From bb366931558f85cc900009d45a53141d165d0742 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Tue, 31 Jul 2018 08:57:46 +0100
Subject: [PATCH] lib: refactor, txnTieKnot automatically

---
 hledger-lib/Hledger/Data/TransactionModifier.hs | 13 ++++++++-----
 hledger-lib/Hledger/Read/Common.hs              |  7 +++----
 hledger/Hledger/Cli/Commands/Rewrite.hs         |  6 ++----
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/hledger-lib/Hledger/Data/TransactionModifier.hs b/hledger-lib/Hledger/Data/TransactionModifier.hs
index 22f31dee5..a15d53b83 100644
--- a/hledger-lib/Hledger/Data/TransactionModifier.hs
+++ b/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
diff --git a/hledger-lib/Hledger/Read/Common.hs b/hledger-lib/Hledger/Read/Common.hs
index 739356bd5..28fcb2a92 100644
--- a/hledger-lib/Hledger/Read/Common.hs
+++ b/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.
diff --git a/hledger/Hledger/Cli/Commands/Rewrite.hs b/hledger/Hledger/Cli/Commands/Rewrite.hs
index a417a2eb0..a07a7e3b8 100755
--- a/hledger/Hledger/Cli/Commands/Rewrite.hs
+++ b/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'