journal: also support lot dates ([DATE])

hledger-lib/Hledger/Read/Common.hs

@@ -137,6 +137,7 @@ import Text.Megaparsec
 import Text.Megaparsec.Char
 import Text.Megaparsec.Char.Lexer (decimal)
 import Text.Megaparsec.Custom
+import Control.Applicative.Permutations
 
 import Hledger.Data
 import Hledger.Utils
@@ -610,11 +611,11 @@ spaceandamountormissingp =
 amountp :: JournalParser m Amount
 amountp = label "amount" $ do
   let spaces = lift $ skipMany spacenonewline
-  amount <- amountwithoutpricep
-  spaces
-  _elotprice <- optional $ lotpricep <* spaces
-  mprice <- optional $ priceamountp <* spaces
-  _elotprice <- optional $ lotpricep
+  amount <- amountwithoutpricep <* spaces
+  (mprice, _elotprice, _elotdate) <- runPermutation $
+    (,,) <$> toPermutationWithDefault Nothing (Just <$> priceamountp <* spaces)
+         <*> toPermutationWithDefault Nothing (Just <$> lotpricep <* spaces)
+         <*> toPermutationWithDefault Nothing (Just <$> lotdatep <* spaces)
   pure $ amount { aprice = mprice }
 
 -- XXX Just like amountp but don't allow lot prices. Needed for balanceassertionp.
@@ -761,21 +762,33 @@ balanceassertionp = do
     , baposition  = sourcepos
     }
 
--- Parse a Ledger-style fixed {=PRICE} or non-fixed {PRICE} lot price,
--- as a Left or Right Amount respectively.
+-- Parse a Ledger-style fixed {=UNITPRICE} or non-fixed {UNITPRICE}
+-- or fixed {{=TOTALPRICE}} or non-fixed {{TOTALPRICE}} lot price,
+-- and ignore it.
 -- https://www.ledger-cli.org/3.0/doc/ledger3.html#Fixing-Lot-Prices .
-lotpricep :: JournalParser m (Either Amount Amount)
-lotpricep = (do
+lotpricep :: JournalParser m ()
+lotpricep = label "ledger-style lot price" $ do
   char '{'
   doublebrace <- option False $ char '{' >> pure True
-  fixed <- fmap isJust $ optional $ lift (skipMany spacenonewline) >> char '='
+  _fixed <- fmap isJust $ optional $ lift (skipMany spacenonewline) >> char '='
   lift (skipMany spacenonewline)
-  a <- amountwithoutpricep
+  _a <- amountwithoutpricep
   lift (skipMany spacenonewline)
   char '}'
   when (doublebrace) $ void $ char '}'
-  return $ (if fixed then Left else Right) a
-  ) <?> "ledger-style lot price or fixed lot price"
+  return ()
+
+-- Parse a Ledger-style lot date [DATE], and ignore it.
+-- https://www.ledger-cli.org/3.0/doc/ledger3.html#Fixing-Lot-Prices .
+lotdatep :: JournalParser m ()
+lotdatep = (do
+  char '['
+  lift (skipMany spacenonewline)
+  _d <- datep
+  lift (skipMany spacenonewline)
+  char ']'
+  return ()
+  ) <?> "ledger-style lot date"
 
 -- | Parse a string representation of a number for its value and display
 -- attributes.

hledger-lib/Hledger/Read/JournalReader.hs

@@ -862,6 +862,9 @@ tests_JournalReader = tests "JournalReader" [
     ,test "lot price before transaction price" $ assertParse (postingp Nothing) "  a  1A {1B} @ 1B\n"
     ,test "lot price after transaction price" $ assertParse (postingp Nothing) "  a  1A @ 1B {1B}\n"
     ,test "lot price after balance assertion not allowed" $ assertParseError (postingp Nothing) "  a  1A @ 1B = 1A {1B}\n" "unexpected '{'"
+    ,test "only lot date" $ assertParse (postingp Nothing) "  a  1A [2000-01-01]\n"
+    ,test "transaction price, lot price, lot date" $ assertParse (postingp Nothing) "  a  1A @ 1B {1B} [2000-01-01]\n"
+    ,test "lot date, lot price, transaction price" $ assertParse (postingp Nothing) "  a  1A [2000-01-01] {1B} @ 1B\n"
 
     ,test "balance assertion over entire contents of account" $ assertParse (postingp Nothing) "  a  $1 == $1\n"
     ]

hledger-lib/hledger_journal.m4.md

@@ -579,18 +579,16 @@ $ hledger bal -N --flat -B
                 €100  assets:euros
 ```
 
-## Lot Prices
+## Lot Prices and Lot Dates
 
 Ledger allows another kind of price, 
-[lot price](http://ledger-cli.org/3.0/doc/ledger3.html#Fixing-Lot-Prices),
-to be specified in curly braces
-(three variants: `{UNITPRICE}`, `{{TOTALPRICE}}`, `{=FIXEDUNITPRICE}`).
-This is normally used to select a lot when selling investments.
-hledger will parse these, for compatibility with Ledger journals, but
-currently ignores them.
-They may appear after the posting amount, before or after the
-[transaction price](#transaction-prices) if any, and before the
-balance assertion if any.
+[lot price](http://ledger-cli.org/3.0/doc/ledger3.html#Fixing-Lot-Prices)
+(four variants: `{UNITPRICE}`, `{{TOTALPRICE}}`, `{=FIXEDUNITPRICE}`, `{{=FIXEDTOTALPRICE}}`),
+and/or a lot date (`[DATE]`) to be specified.
+These are normally used to select a lot when selling investments.
+hledger will parse these, for compatibility with Ledger journals, but currently ignores them.
+A [transaction price](#transaction-prices), lot price and/or lot date may appear in any order,
+after the posting amount and before the balance assertion if any.
 
 ## Balance Assertions