1 files changed, 106 insertions, 0 deletions
diff --git a/bootstrap/src/BuildModel.hs b/bootstrap/src/BuildModel.hs
index b8bc122..dab8aed 100644
--- a/bootstrap/src/BuildModel.hs
+++ b/bootstrap/src/BuildModel.hs
@@ -1,10 +1,31 @@
 module BuildModel where
 
+import           Control.Applicative            ( (<|>) )
+import           Data.Char                      ( isAsciiLower
+                                                , isDigit
+                                                , toLower
+                                                )
+import           Data.Maybe                     ( fromMaybe
+                                                , mapMaybe
+                                                )
 import           Data.List                      ( intercalate )
 import           System.FilePath                ( (</>)
                                                 , (<.>)
                                                 , splitDirectories
                                                 )
+import           Text.ParserCombinators.ReadP   ( ReadP
+                                                , char
+                                                , eof
+                                                , many
+                                                , many1
+                                                , option
+                                                , readP_to_S
+                                                , satisfy
+                                                , skipSpaces
+                                                , string
+                                                )
+
+data LineContents = ModuleUsed String | Other
 
 data RawSource = RawSource {
     rawSourceFilename :: FilePath
@@ -14,6 +35,7 @@ data RawSource = RawSource {
 data Source = Program {
     programSourceFileName :: FilePath
   , programObjectFileName :: FilePath -> FilePath
+  , programModulesUsed :: [String]
 }
 
 processRawSource :: RawSource -> Source
@@ -27,8 +49,92 @@ processRawSource rawSource =
                                             sourceFileName
                                           )
                                       <.> "o"
+        , programModulesUsed    = getModulesUsed rawSource
         }
 
 pathSeparatorsToUnderscores :: FilePath -> FilePath
 pathSeparatorsToUnderscores fileName =
   intercalate "_" (splitDirectories fileName)
+
+getModulesUsed :: RawSource -> [String]
+getModulesUsed rawSource =
+  let fileLines    = lines $ rawSourceContents rawSource
+      lineContents = map parseFortranLine fileLines
+  in  contentsToModuleNames lineContents
+
+contentsToModuleNames :: [LineContents] -> [String]
+contentsToModuleNames = mapMaybe contentToMaybeModuleName
+ where
+  contentToMaybeModuleName content = case content of
+    ModuleUsed moduleName -> Just moduleName
+    _                     -> Nothing
+
+readFileLinesIO :: FilePath -> IO [String]
+readFileLinesIO file = do
+  contents <- readFile file
+  return $ lines contents
+
+parseFortranLine :: String -> LineContents
+parseFortranLine line =
+  let line'  = map toLower line
+      result = readP_to_S doFortranLineParse line'
+  in  getResult result
+ where
+  getResult (_ : (contents, _) : _) = contents
+  getResult [(contents, _)        ] = contents
+  getResult []                      = Other
+
+doFortranLineParse :: ReadP LineContents
+doFortranLineParse = option Other fortranUsefulContents
+
+fortranUsefulContents :: ReadP LineContents
+fortranUsefulContents = useStatement
+
+useStatement :: ReadP LineContents
+useStatement = do
+  skipSpaces
+  _ <- string "use"
+  skipAtLeastOneWhiteSpace
+  modName <- validIdentifier
+  skipSpaceCommaOrEnd
+  return $ ModuleUsed modName
+
+skipAtLeastOneWhiteSpace :: ReadP ()
+skipAtLeastOneWhiteSpace = do
+  _ <- many1 whiteSpace
+  return ()
+
+skipSpaceOrEnd :: ReadP ()
+skipSpaceOrEnd = eof <|> skipAtLeastOneWhiteSpace
+
+skipSpaceCommaOrEnd :: ReadP ()
+skipSpaceCommaOrEnd = eof <|> skipComma <|> skipAtLeastOneWhiteSpace
+
+skipComma :: ReadP ()
+skipComma = do
+  _ <- char ','
+  return ()
+
+whiteSpace :: ReadP Char
+whiteSpace = satisfy (`elem` " \t")
+
+validIdentifier :: ReadP String
+validIdentifier = do
+  first <- validFirstCharacter
+  rest  <- many validIdentifierCharacter
+  return $ first : rest
+
+validFirstCharacter :: ReadP Char
+validFirstCharacter = alphabet
+
+validIdentifierCharacter :: ReadP Char
+validIdentifierCharacter = alphabet <|> digit <|> underscore
+
+alphabet :: ReadP Char
+alphabet = satisfy isAsciiLower
+
+digit :: ReadP Char
+digit = satisfy isDigit
+
+underscore :: ReadP Char
+underscore = char '_'