diff --git a/hledger-lib/Hledger/Read.hs b/hledger-lib/Hledger/Read.hs
index 477b84ca7..6a68560ac 100644
--- a/hledger-lib/Hledger/Read.hs
+++ b/hledger-lib/Hledger/Read.hs
@@ -87,7 +87,6 @@ This is used by the import command.
 module Hledger.Read (
 
   -- * Journal files
-  PrefixedFilePath,
   defaultJournal,
   defaultJournalWith,
   defaultJournalSafely,
@@ -227,10 +226,6 @@ defaultJournalPath = do
         home <- fromMaybe "" <$> getHomeSafe
         return $ home </> journalDefaultFilename
 
--- | A file path optionally prefixed by a reader name and colon
--- (journal:, csv:, timedot:, etc.).
-type PrefixedFilePath = FilePath
-
 -- | @readJournal iopts mfile txt@
 --
 -- Read a Journal from some handle, with strict checks if enabled,
diff --git a/hledger-lib/Hledger/Read/Common.hs b/hledger-lib/Hledger/Read/Common.hs
index 7b7efbfe0..7bddc2ad8 100644
--- a/hledger-lib/Hledger/Read/Common.hs
+++ b/hledger-lib/Hledger/Read/Common.hs
@@ -30,6 +30,8 @@ Some of these might belong in Hledger.Read.JournalReader or Hledger.Read.
 --- ** exports
 module Hledger.Read.Common (
   Reader (..),
+  PrefixedFilePath,
+  isStdin,
   InputOpts(..),
   HasInputOpts(..),
   definputopts,
@@ -193,6 +195,17 @@ data Reader m = Reader {
 
 instance Show (Reader m) where show r = show (rFormat r) ++ " reader"
 
+-- | A file path optionally prefixed by a reader name and colon (journal:, csv:, timedot:, etc.).
+-- The file path part can also be - meaning standard input.
+type PrefixedFilePath = FilePath
+
+-- | Is this the special file path meaning standard input ? (-, possibly prefixed)
+isStdin :: PrefixedFilePath -> Bool
+isStdin f = case splitAtElement ':' f of
+  [_,"-"] -> True
+  ["-"] -> True
+  _ -> False
+
 -- | Parse an InputOpts from a RawOpts and a provided date.
 -- This will fail with a usage error if the forecast period expression cannot be parsed.
 rawOptsToInputOpts :: Day -> Bool -> Bool -> RawOpts -> InputOpts
diff --git a/hledger-lib/Hledger/Read/JournalReader.hs b/hledger-lib/Hledger/Read/JournalReader.hs
index 8f2741ca8..deed48299 100644
--- a/hledger-lib/Hledger/Read/JournalReader.hs
+++ b/hledger-lib/Hledger/Read/JournalReader.hs
@@ -167,14 +167,6 @@ findReader Nothing (Just path) =
     (prefix,path') = splitReaderPrefix path
     ext            = map toLower $ drop 1 $ takeExtension path'
 
--- | A prefix used to specify a particular reader to be used for a file path,
--- overriding the file extension. It is a valid reader name followed by a colon.
--- Eg journal:, csv:, timeclock:, timedot:.
--- type ReaderPrefix = String
-
--- | A file path with an optional reader prefix.
-type PrefixedFilePath = FilePath
-
 -- | Separate a file path and its reader prefix, if any.
 --
 -- >>> splitReaderPrefix "csv:-"
diff --git a/hledger/Hledger/Cli/Commands/Run.hs b/hledger/Hledger/Cli/Commands/Run.hs
index 405957ed8..d55c68aa0 100644
--- a/hledger/Hledger/Cli/Commands/Run.hs
+++ b/hledger/Hledger/Cli/Commands/Run.hs
@@ -241,7 +241,7 @@ withJournalCached defaultJournalOverride cliopts cmd = do
             return (cache, journal)
           Nothing -> do
             dbg1IO ("readAndCacheJournalFile reading and caching "++fp) iopts
-            journal <- runExceptT $ if snd (splitReaderPrefix fp) == "-" then readStdin else readJournalFile iopts fp
+            journal <- runExceptT $ if isStdin fp then readStdin else readJournalFile iopts fp
             either error' (\j -> return (Map.insert (ioptsWithoutReportSpan,fp) j cache, j)) journal
       where
         -- InputOptions contain reportspan_ that is used to calculate forecast period,
@@ -257,7 +257,7 @@ withJournalCached defaultJournalOverride cliopts cmd = do
               -- forecast transactions are never generated before journal end
               -- unless specifically requested).
               Just forecastspan -> forecastspan `spanValidDefaultsFrom` reportspan_ iopts
-        -- Read stdin, or if we read it alread, use a cache
+        -- Read stdin, or if we read it already, use a cache
         -- readStdin :: InputOpts -> ExceptT String IO Journal
         readStdin = do
           stdinContent <- liftIO $ modifyMVar stdinCache $ \cache ->