mostly replace slow regexpr with regex-tdfa (fixes #189)

hledger-lib/Hledger/Read/CsvReader.hs

@@ -655,7 +655,7 @@ getEffectiveAssignment rules record f = lastMay $ assignmentsFor f
                 matcherMatches pats = patternMatches $  "(" ++ intercalate "|" pats ++ ")"
                   where
                     patternMatches :: Regexp -> Bool
-                    patternMatches pat = regexMatchesCIRegexCompat pat csvline
+                    patternMatches pat = regexMatchesCI pat csvline
                       where
                         csvline = intercalate "," record
 

hledger-lib/Hledger/Read/JournalReader.hs

@@ -81,7 +81,7 @@ detect :: FilePath -> String -> Bool
 detect f s
   | f /= "-"  = takeExtension f `elem` ['.':format, ".j"]  -- from a file: yes if the extension is .journal or .j
   -- from stdin: yes if we can see something that looks like a journal entry (digits in column 0 with the next line indented)
-  | otherwise = isJust $ regexMatch "^[0-9]+.*\n[ \t]+" s
+  | otherwise = regexMatches "^[0-9]+.*\n[ \t]+" s
 
 -- | Parse and post-process a "Journal" from hledger's journal file
 -- format, or give an error.

hledger-lib/Hledger/Utils/Regex.hs

@@ -1,11 +1,28 @@
--- Regular expression helpers.
--- Currently using mostly regexpr and some regex-tdfa.
--- Note many of these will die on malformed regexps.
+{-# LANGUAGE ScopedTypeVariables #-}
+{-
+
+Easy regular expression helpers.
+
+These should
+- have mnemonic names
+- have simple monomorphic types
+- work with strings
+- support extended regular expressions
+- support replacement
+- support splitting
+- support unicode
+- be cross-platform, not requiring C libraries
+
+They currently can
+- die on malformed regexps
+- be slow (regexpr)
+
+-}
 
 module Hledger.Utils.Regex (
-   regexMatch
-  ,regexMatchCI
-  ,regexMatches
+  --  regexMatch
+  -- ,regexMatchCI
+   regexMatches
   ,regexMatchesCI
   ,containsRegex
   ,regexReplace
@@ -13,47 +30,89 @@ module Hledger.Utils.Regex (
   ,regexReplaceBy
   ,regexToCaseInsensitive
   ,regexSplit
-  ,regexMatchesRegexCompat
-  ,regexMatchesCIRegexCompat
+  ,toRegex
   )
 where
-import Data.Maybe
-import Text.Regex.TDFA
-import Text.RegexPR
 
--- regexMatch :: String -> String -> MatchFun Maybe
-regexMatch r s = matchRegexPR r s
+import Data.List (foldl')
+import Text.RegexPR (splitRegexPR)
+import Text.Regex.TDFA (
+  Regex, CompOption(..), ExecOption(..), defaultCompOpt, defaultExecOpt,
+  makeRegexOpts, AllMatches(getAllMatches), match, (=~)
+  )
 
--- regexMatchCI :: String -> String -> MatchFun Maybe
-regexMatchCI r s = regexMatch (regexToCaseInsensitive r) s
 
-regexMatches :: String -> String -> Bool
-regexMatches r s = isJust $ matchRegexPR r s
-
-regexMatchesCI :: String -> String -> Bool
-regexMatchesCI r s = regexMatches (regexToCaseInsensitive r) s
+type Regexp = String
+type Replacement = String
 
+containsRegex :: Regexp -> String -> Bool
 containsRegex = regexMatchesCI
 
-regexReplace :: String -> String -> String -> String
-regexReplace r repl s = gsubRegexPR r repl s
-
-regexReplaceCI :: String -> String -> String -> String
-regexReplaceCI r s = regexReplace (regexToCaseInsensitive r) s
-
-regexReplaceBy :: String -> (String -> String) -> String -> String
-regexReplaceBy r replfn s = gsubRegexPRBy r replfn s
-
-regexToCaseInsensitive :: String -> String
+regexToCaseInsensitive :: Regexp -> Regexp
 regexToCaseInsensitive r = "(?i)"++ r
 
-regexSplit :: String -> String -> [String]
+-- regexpr - may be slow
+
+regexSplit :: Regexp -> String -> [Regexp]
 regexSplit = splitRegexPR
 
--- regex-compat (regex-posix) functions that perform better than regexpr.
-regexMatchesRegexCompat :: String -> String -> Bool
-regexMatchesRegexCompat = flip (=~)
+-- regexMatch :: Regexp -> String -> MatchFun Maybe
+-- regexMatch r s = matchRegexPR r s
 
-regexMatchesCIRegexCompat :: String -> String -> Bool
-regexMatchesCIRegexCompat r = match (makeRegexOpts defaultCompOpt { multiline = True, caseSensitive = False, newSyntax = True } defaultExecOpt r)
+-- regexMatchCI :: Regexp -> String -> MatchFun Maybe
+-- regexMatchCI r s = regexMatch (regexToCaseInsensitive r) s
+
+-- regexMatches :: Regexp -> String -> Bool
+-- regexMatches r s = isJust $ matchRegexPR r s
+
+-- regexMatchesCI :: Regexp -> String -> Bool
+-- regexMatchesCI r s = regexMatches (regexToCaseInsensitive r) s
+
+-- regexReplace :: Regexp -> Replacement -> String -> String
+-- regexReplace r repl s = gsubRegexPR r repl s
+
+-- regexReplaceCI :: Regexp -> Replacement -> String -> String
+-- regexReplaceCI r s = regexReplace (regexToCaseInsensitive r) s
+
+-- regexReplaceBy :: Regexp -> (String -> Replacement) -> String -> String
+-- regexReplaceBy r replfn s = gsubRegexPRBy r replfn s
+
+-- regex-tdfa
+
+compOpt :: CompOption
+compOpt = defaultCompOpt
+
+execOpt :: ExecOption
+execOpt = defaultExecOpt
+
+toRegex :: Regexp -> Regex
+toRegex = makeRegexOpts compOpt execOpt
+
+-- regexMatch' :: RegexContext Regexp String a => Regexp -> String -> a
+-- regexMatch' r s = s =~ (toRegex r)
+
+regexMatches :: Regexp -> String -> Bool
+regexMatches = flip (=~)
+
+regexMatchesCI :: Regexp -> String -> Bool
+regexMatchesCI r = match (makeRegexOpts compOpt{caseSensitive=False} execOpt r)
+
+regexReplace :: Regexp -> Replacement -> String -> String
+regexReplace r repl = regexReplaceBy r (const repl)
+
+regexReplaceCI :: Regexp -> Replacement -> String -> String
+regexReplaceCI r s = regexReplace (regexToCaseInsensitive r) s
+
+regexReplaceBy :: Regexp -> (String -> Replacement) -> String -> String
+regexReplaceBy r = replaceAll (toRegex r)
+
+-- from http://stackoverflow.com/questions/9071682/replacement-substition-with-haskell-regex-libraries
+replaceAll :: Regex -> (String -> Replacement) -> String -> String
+replaceAll re f s = start end
+  where
+    (_, end, start) = foldl' go (0, s, id) $ getAllMatches $ match re s
+    go (ind,read,write) (off,len) =
+      let (skip, start) = splitAt (off - ind) read 
+          (matched, remaining) = splitAt len start 
+      in (off + len, remaining, write . (skip++) . (f matched ++))
 

hledger/Hledger/Cli/Utils.hs

@@ -34,6 +34,8 @@ import System.Process (readProcessWithExitCode)
 import System.Time (ClockTime, getClockTime, diffClockTimes, TimeDiff(TimeDiff))
 import Test.HUnit
 import Text.Printf
+import Text.Regex.TDFA (match)
+
 
 -- kludge - adapt to whichever directory version is installed, or when
 -- cabal macros aren't available, assume the new directory
@@ -179,7 +181,8 @@ safeGetDirectoryContents "" = getDirectoryContents "."
 safeGetDirectoryContents fp = getDirectoryContents fp
 
 -- | Does the second file represent a backup of the first, and if so which version is it ?
+-- XXX nasty regex types intruding, add a simpler api to Hledger.Utils.Regex
 backupNumber :: FilePath -> FilePath -> Maybe Int
-backupNumber f g = case regexMatch ("^" ++ f ++ "\\.([0-9]+)$") g of
-                        Just (_, ((_,suffix):_)) -> readMay suffix
+backupNumber f g = case match (toRegex ("^" ++ f ++ "\\.([0-9]+)$")) g of
+                        (_::FilePath, _::FilePath, _::FilePath, [ext::FilePath]) -> readMay ext
                         _ -> Nothing

hledger/hledger.cabal

@@ -80,6 +80,7 @@ library
                  ,old-time
                  ,parsec
                  ,process
+                 ,regex-tdfa
                  ,regexpr >= 0.5.1
                  ,safe >= 0.2
 -- http://www.yesodweb.com/blog/2014/04/consolidation-progress
@@ -149,6 +150,7 @@ executable hledger
                  ,old-time
                  ,parsec
                  ,process
+                 ,regex-tdfa
                  ,regexpr >= 0.5.1
                  ,safe >= 0.2
                  ,shakespeare-text >= 1.0 && < 1.2
@@ -183,6 +185,7 @@ test-suite tests
                , old-time
                , parsec
                , process
+               , regex-tdfa
                , regexpr
                , safe
                , shakespeare-text >= 1.0 && < 1.2