ch08: Copy a needed file from the examples

1 files changed, 55 insertions, 0 deletions

diff --git a/ch08/GlobRegex.hs b/ch08/GlobRegex.hs
new file mode 100644
index 0000000..1b847f4
--- /dev/null
+++ b/ch08/GlobRegex.hs
@@ -0,0 +1,55 @@
+{-- snippet type --}

+module GlobRegex

+    (

+      globToRegex

+    , matchesGlob

+    ) where

+

+import Text.Regex.Posix ((=~))

+

+globToRegex :: String -> String

+{-- /snippet type --}

+

+{-- snippet rooted --}

+globToRegex cs = '^' : globToRegex' cs ++ "$"

+{-- /snippet rooted --}

+

+{-- snippet asterisk --}

+globToRegex' :: String -> String

+globToRegex' "" = ""

+

+globToRegex' ('*':cs) = ".*" ++ globToRegex' cs

+

+globToRegex' ('?':cs) = '.' : globToRegex' cs

+

+globToRegex' ('[':'!':c:cs) = "[^" ++ c : charClass cs

+globToRegex' ('[':c:cs)     = '['  :  c : charClass cs

+globToRegex' ('[':_)        = error "unterminated character class"

+

+globToRegex' (c:cs) = escape c ++ globToRegex' cs

+{-- /snippet asterisk --}

+

+{-

+{-- snippet last --}

+globToRegex' (c:cs) = escape c ++ globToRegex' cs

+{-- /snippet last --}

+-}

+

+{-- snippet escape --}

+escape :: Char -> String

+escape c | c `elem` regexChars = '\\' : [c]

+         | otherwise = [c]

+    where regexChars = "\\+()^$.{}]|"

+{-- /snippet escape --}

+

+{-- snippet charClass --}

+charClass :: String -> String

+charClass (']':cs) = ']' : globToRegex' cs

+charClass (c:cs)   = c : charClass cs

+charClass []       = error "unterminated character class"

+{-- /snippet charClass --}

+

+{-- snippet matchesGlob --}

+matchesGlob :: FilePath -> String -> Bool

+name `matchesGlob` pat = name =~ globToRegex pat

+{-- /snippet matchesGlob --}