diff --git a/hledger-lib/Hledger/Data/PeriodicTransaction.hs b/hledger-lib/Hledger/Data/PeriodicTransaction.hs
index 153d67e87..3f986cff5 100644
--- a/hledger-lib/Hledger/Data/PeriodicTransaction.hs
+++ b/hledger-lib/Hledger/Data/PeriodicTransaction.hs
@@ -45,6 +45,17 @@ _ptgen str = do
           nullperiodictransaction{ ptperiodexpr=t , ptspan=s, ptinterval=i, ptpostings=["a" `post` usd 1] }
           nulldatespan
 
+_ptgenspan str span = do
+  let
+    t = T.pack str
+    (i,s) = parsePeriodExpr' nulldate t
+  case checkPeriodicTransactionStartDate i s t of
+    Just e  -> error' e
+    Nothing ->
+      mapM_ (putStr . showTransaction) $
+        runPeriodicTransaction
+          nullperiodictransaction{ ptperiodexpr=t , ptspan=s, ptinterval=i, ptpostings=["a" `post` usd 1] }
+          span
 
 --deriving instance Show PeriodicTransaction
 -- for better pretty-printing:
@@ -199,6 +210,28 @@ instance Show PeriodicTransaction where
 -- >>> let reportperiod="daily from 2018/01/03" in let (i,s) = parsePeriodExpr' nulldate reportperiod in runPeriodicTransaction (nullperiodictransaction{ptperiodexpr=reportperiod, ptspan=s, ptinterval=i, ptpostings=["a" `post` usd 1]}) (DateSpan (Just $ parsedate "2018-01-01") (Just $ parsedate "2018-01-03"))
 -- []
 --
+-- >>> _ptgenspan "every 3 months from 2019-05" (mkdatespan "2020-01-01" "2020-02-01")
+--  
+-- >>> _ptgenspan "every 3 months from 2019-05" (mkdatespan "2020-02-01" "2020-03-01")
+-- 2020/02/01
+--     ; generated-transaction:~ every 3 months from 2019-05
+--     a           $1.00
+-- <BLANKLINE>
+-- >>> _ptgenspan "every 3 days from 2018" (mkdatespan "2018-01-01" "2018-01-05")
+-- 2018/01/01
+--     ; generated-transaction:~ every 3 days from 2018
+--     a           $1.00
+-- <BLANKLINE>
+-- 2018/01/04
+--     ; generated-transaction:~ every 3 days from 2018
+--     a           $1.00
+-- <BLANKLINE>
+-- >>> _ptgenspan "every 3 days from 2018" (mkdatespan "2018-01-02" "2018-01-05")
+-- 2018/01/04
+--     ; generated-transaction:~ every 3 days from 2018
+--     a           $1.00
+-- <BLANKLINE>
+
 runPeriodicTransaction :: PeriodicTransaction -> DateSpan -> [Transaction]
 runPeriodicTransaction PeriodicTransaction{..} requestedspan =
     [ t{tdate=d} | (DateSpan (Just d) _) <- alltxnspans, spanContainsDate requestedspan d ]