From f5d1d49e3320e3f5407f77f232e4dcb1bb5ba380 Mon Sep 17 00:00:00 2001
From: Jan Sucan <jan@jansucan.com>
Date: Sun, 3 Sep 2023 11:57:33 +0200
Subject: 8_c_2: Add solution

---
 ch08/8_c_1.hs | 79 -----------------------------------------------------------
 1 file changed, 79 deletions(-)
 delete mode 100644 ch08/8_c_1.hs

(limited to 'ch08/8_c_1.hs')

diff --git a/ch08/8_c_1.hs b/ch08/8_c_1.hs
deleted file mode 100644
index ce80ade..0000000
--- a/ch08/8_c_1.hs
+++ /dev/null
@@ -1,79 +0,0 @@
--- Write a version of globToRegex that uses the type signature earlier.
-
-{-- From examples/examples/ch08/GlobRegex.hs modified according to the assignment --}
-import Text.Regex.Posix ((=~))
-
-type GlobError = String
-
-globToRegex :: String -> Either GlobError String
-
-globToRegex cs = propagateError regex
-  where regex = globToRegex' cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right ('^' : s ++ "$")
-
-globToRegex' :: String -> Either GlobError String
-globToRegex' "" = Right ""
-
-globToRegex' ('*':cs) = propagateError regex
-  where regex = globToRegex' cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right (".*" ++ s)
-
-globToRegex' ('?':cs) = propagateError regex
-  where regex = globToRegex' cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right ("." ++ s)
-
-globToRegex' ('[':'!':c:cs) = propagateError charCls
-  where charCls = charClass cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right ("[^" ++ c : s)
-
-globToRegex' ('[':c:cs) = propagateError charCls
-  where charCls = charClass cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right ('['  :  c : s)
-
-globToRegex' ('[':_) = Left "unterminated character class"
-
-globToRegex' (c:cs) = propagateError regex
-  where regex = globToRegex' cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right ((escape c) ++ s)
-
-
-escape :: Char -> String
-escape c | c `elem` regexChars = '\\' : [c]
-         | otherwise = [c]
-    where regexChars = "\\+()^$.{}]|"
-
-
-charClass :: String -> Either GlobError String
-
-charClass (']':cs) = propagateError regex
-  where regex = globToRegex' cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right (']' : s)
-
-charClass (c:cs) = propagateError charCls
-  where charCls = charClass cs
-        propagateError (Left e) = Left e
-        propagateError (Right s) = Right (c : s)
-
-charClass [] = Left "unterminated character class"
-{-- End of code from examples --}
-
-
--- ghci> :l 8_c_1.hs
--- [1 of 1] Compiling Main             ( 8_c_1.hs, interpreted )
--- Ok, one module loaded.
-
--- ghci> globToRegex "["
--- Left "unterminated character class"
-
--- ghci> globToRegex "[]"
--- Left "unterminated character class"
-
--- ghci> globToRegex "a?b*c[!DE][FG]+"
--- Right "^a.b.*c[^DE][FG]\\+$"
-- 
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