Web.Util.String → {Web.Util.Url, Core.Util.String}

1 files changed, 48 insertions, 0 deletions

diff --git a/src/Hakyll/Core/Util/String.hs b/src/Hakyll/Core/Util/String.hs
new file mode 100644
index 0000000..7f75a36
--- /dev/null
+++ b/src/Hakyll/Core/Util/String.hs
@@ -0,0 +1,48 @@
+-- | Miscellaneous string manipulation functions.
+--
+module Hakyll.Core.Util.String
+    ( trim
+    , replaceAll
+    , splitAll
+    ) where
+
+import Data.Char (isSpace)
+import Data.Maybe (listToMaybe)
+
+import Text.Regex.PCRE ((=~~))
+
+-- | Trim a string (drop spaces, tabs and newlines at both sides).
+--
+trim :: String -> String
+trim = reverse . trim' . reverse . trim'
+  where
+    trim' = dropWhile isSpace
+
+-- | A simple (but inefficient) regex replace funcion
+--
+replaceAll :: String              -- ^ Pattern
+           -> (String -> String)  -- ^ Replacement (called on capture)
+           -> String              -- ^ Source string
+           -> String              -- ^ Result
+replaceAll pattern f source = replaceAll' source
+  where
+    replaceAll' src = case listToMaybe (src =~~ pattern) of
+        Nothing     -> src
+        Just (o, l) ->
+            let (before, tmp) = splitAt o src
+                (capture, after) = splitAt l tmp
+            in before ++ f capture ++ replaceAll' after
+
+-- | A simple regex split function. The resulting list will contain no empty
+-- strings.
+--
+splitAll :: String    -- ^ Pattern
+         -> String    -- ^ String to split
+         -> [String]  -- ^ Result
+splitAll pattern = filter (not . null) . splitAll'
+  where
+    splitAll' src = case listToMaybe (src =~~ pattern) of
+        Nothing     -> [src]
+        Just (o, l) ->
+            let (before, tmp) = splitAt o src
+            in before : splitAll' (drop l tmp)