Move away from regexes for basic String matching

This leverages simpler tests to determine matches over regular
expressions

src/Unused/ResponseFilter.hs

@@ -10,7 +10,7 @@ module Unused.ResponseFilter
 
 import qualified Data.Map.Strict as Map
 import Data.List (isInfixOf, isPrefixOf, isSuffixOf)
-import Unused.Regex (matchRegex)
+import qualified Data.Char as C
 import Unused.Types
 import Unused.ResultsClassifier
 
@@ -35,7 +35,11 @@ includesLikelihood :: [RemovalLikelihood] -> TermResults -> Bool
 includesLikelihood l = (`elem` l) . rLikelihood . trRemoval
 
 isClassOrModule :: TermResults -> Bool
-isClassOrModule = matchRegex "^[A-Z]" . trTerm
+isClassOrModule =
+    startsWithUpper . trTerm
+  where
+    startsWithUpper [] = False
+    startsWithUpper (a:_) = C.isUpper a
 
 autoLowLikelihood :: LanguageConfiguration -> TermResults -> Bool
 autoLowLikelihood l r =
@@ -55,15 +59,15 @@ classOrModuleFunction True = isClassOrModule
 classOrModuleFunction False = const True
 
 matcherToBool :: Matcher -> TermResults -> Bool
-matcherToBool (Path p v) = any (positionToRegex p v) . paths
-matcherToBool (Term p v) = positionToRegex p v . trTerm
+matcherToBool (Path p v) = any (positionToTest p v) . paths
+matcherToBool (Term p v) = positionToTest p v . trTerm
 matcherToBool (AppOccurrences i) = (== i) . appOccurrenceCount
-matcherToBool (AllowedTerms ts) = flip isAllowedTerm ts
+matcherToBool (AllowedTerms ts) = (`isAllowedTerm` ts)
 
-positionToRegex :: Position -> (String -> String -> Bool)
-positionToRegex StartsWith = isPrefixOf
-positionToRegex EndsWith = isSuffixOf
-positionToRegex Equals = (==)
+positionToTest :: Position -> (String -> String -> Bool)
+positionToTest StartsWith = isPrefixOf
+positionToTest EndsWith = isSuffixOf
+positionToTest Equals = (==)
 
 paths :: TermResults -> [String]
 paths r = tmPath <$> trMatches r

src/Unused/TagsSource.hs

@@ -6,9 +6,8 @@ module Unused.TagsSource
     , loadTagsFromPipe
     ) where
 
-import Data.List (nub)
+import Data.List (isPrefixOf, nub)
 import System.Directory (findFile)
-import Unused.Regex (matchRegex)
 import qualified Data.Text as T
 
 data TagSearchOutcome
@@ -22,13 +21,13 @@ loadTagsFromFile = fmap (fmap tokensFromTags) tagsContent
 
 tokensFromTags :: String -> [String]
 tokensFromTags =
-    filter tagRemovalRegex . nub . map token . tokenLocations
+    filter validTokens . nub . tokenLocations
   where
-    tokenLocations = map (T.splitOn "\t" . T.pack) . lines
+    tokenLocations = map (token . T.splitOn "\t" . T.pack) . lines
     token = T.unpack . head
 
-tagRemovalRegex :: String -> Bool
-tagRemovalRegex = not . matchRegex "^!_TAG"
+validTokens :: String -> Bool
+validTokens = not . isPrefixOf "!_TAG"
 
 tagsContent :: IO (Either TagSearchOutcome String)
 tagsContent = findFile possibleTagsFileDirectories "tags" >>= eitherReadFile

src/Unused/TermSearch/Internal.hs

@@ -7,8 +7,8 @@ module Unused.TermSearch.Internal
 
 import Data.Maybe (fromMaybe)
 import qualified Data.Text as T
+import qualified Data.Char as C
 import Unused.Types (TermMatch(..))
-import Unused.Regex
 import Unused.Util (stringToInt)
 
 commandLineOptions :: String -> [String]
@@ -29,4 +29,6 @@ parseSearchResult term s =
 
 regexSafeTerm :: String -> Bool
 regexSafeTerm =
-    matchRegex "^[[:word:]]+$"
+    all regexSafeChar
+  where
+    regexSafeChar c = C.isAlphaNum c || c == '_' || c == '-'