Added a system for specifying implicitly-used modules on the command-line

An implicitly used module is equivalent to a #USE directive before the first line of the main file.  This, combined with changes in occbuild, are my current way of implementing the automatic use of the forall module in occam.

Main.hs

@@ -73,6 +73,7 @@ optionsNoWarnings =
   , Option [] ["external-link"] (ReqArg optCompilerLinkFlags "FLAGS") "link flags for C/C++ compiler"
   , Option [] ["run-indent"] (NoArg $ optRunIndent) "run indent on source before compilation (will full mode)"
   , Option [] ["frontend"] (ReqArg optFrontend "FRONTEND") "language frontend (options: occam, rain)"
+  , Option ['u'] ["implicit-module"] (ReqArg optImplicitModule "MODULE") "implicitly use this module"
   , Option [] ["include-path"] (NoArg $ optPrintPath tockIncludeDir) "print include path"
   , Option [] ["lib-path"] (NoArg $ optPrintPath tockLibDir) "print lib path"
   , Option [] ["mode"] (ReqArg optMode "MODE") "select mode (options: flowgraph, lex, html, parse, compile, post-c, full)"
@@ -136,6 +137,9 @@ optSearchPath s ps = return $ ps { csSearchPath = csSearchPath ps ++ splitOnColo
       (p, _:more) -> p : splitOnColons more
       (p, []) -> [p]
 
+optImplicitModule :: String -> OptFunc
+optImplicitModule s ps = return $ ps { csImplicitModules = csImplicitModules ps ++ [s] }
+
 optCompilerFlags :: String -> OptFunc
 optCompilerFlags flags ps = return $ ps { csCompilerFlags = flags ++ " " ++ csCompilerFlags ps}
 

data/CompState.hs

@@ -119,6 +119,7 @@ data CompState = CompState {
     csClassicOccamMobility :: Bool,
     csUnknownStackSize :: Integer,
     csSearchPath :: [String],
+    csImplicitModules :: [String],
 
     -- Set by preprocessor
     csCurrentFile :: String, -- Also used by some later passes!
@@ -181,6 +182,7 @@ emptyState = CompState {
     csClassicOccamMobility = False,
     csUnknownStackSize = 512,
     csSearchPath = [".", tockIncludeDir],
+    csImplicitModules = [],
 
     csCurrentFile = "none",
     csUsedFiles = Set.empty,

frontends/PreprocessOccam.hs

@@ -42,8 +42,8 @@ import StructureOccam
 import Utils
 
 -- | Preprocess a file and return its tokenised form ready for parsing.
-preprocessFile :: Meta -> String -> PassM [Token]
+preprocessFile :: Meta -> [String] -> String -> PassM [Token]
-preprocessFile m filename
+preprocessFile m implicitMods filename
     =  do (handle, realFilename) <- searchFile m filename
           progress $ "Loading source file " ++ realFilename
           origCS <- get
@@ -54,7 +54,7 @@ preprocessFile m filename
           modify (\cs -> cs { csCurrentFile = realFilename
                             , csUsedFiles = modFunc $ csUsedFiles cs })
           s <- liftIO $ hGetContents handle
-          toks <- preprocessSource m realFilename s
+          toks <- preprocessSource m implicitMods realFilename s
           modify (\cs -> cs { csCurrentFile = csCurrentFile origCS })
           return toks
   where
@@ -62,13 +62,13 @@ preprocessFile m filename
     drop9 = reverse . drop 9 . reverse
 
 -- | Preprocesses source directly and returns its tokenised form ready for parsing.
-preprocessSource :: Meta -> String -> String -> PassM [Token]
+preprocessSource :: Meta -> [String] -> String -> String -> PassM [Token]
-preprocessSource m realFilename s
+preprocessSource m implicitMods realFilename s
     =  do toks <- runLexer realFilename $ removeASM s
           veryDebug $ "{{{ lexer tokens"
           veryDebug $ pshow toks
           veryDebug $ "}}}"
-          toks' <- preprocessOccam toks
+          toks' <- preprocessOccam $ incImplicit ++ toks
           veryDebug $ "{{{ preprocessed tokens"
           veryDebug $ pshow toks'
           veryDebug $ "}}}"
@@ -78,6 +78,11 @@ preprocessSource m realFilename s
           veryDebug $ "}}}"
           expandIncludes toks''
   where
+    incImplicit = concat [[Token emptyMeta $ TokPreprocessor $ "#USE \"" ++ f ++ "\""
+--                          ,Token emptyMeta EndOfLine
+                          ]
+                         | f <- implicitMods]
+    
     --ASM blocks tend to screw up the lexer.  Tock is unlikely to support them
     -- any time soon, but at the same time lots of occam code does have ASM blocks,
     -- and even if they are inside a #IFDEF, it will still cause Tock to choke
@@ -119,7 +124,7 @@ preprocessSource m realFilename s
 expandIncludes :: [Token] -> PassM [Token]
 expandIncludes [] = return []
 expandIncludes (Token m (IncludeFile filename) : Token _ EndOfLine : ts)
-    =  do contents <- preprocessFile m filename
+    =  do contents <- preprocessFile m [] filename
           rest <- expandIncludes ts
           return $ contents ++ rest
 expandIncludes (Token m (IncludeFile _) : _)
@@ -414,7 +419,8 @@ runPreprocParser m prod s
 -- | Load and preprocess an occam program.
 preprocessOccamProgram :: String -> PassM [Token]
 preprocessOccamProgram filename
-    =  do toks <- preprocessFile emptyMeta filename
+    =  do mods <- getCompState >>* csImplicitModules
+          toks <- preprocessFile emptyMeta mods filename
           -- Leave the main file name in the csCurrentFile slot:
           modify $ \cs -> cs { csCurrentFile = filename }
           veryDebug $ "{{{ tokenised source"
@@ -424,4 +430,4 @@ preprocessOccamProgram filename
 
 -- | Preprocesses occam source direct from the given String
 preprocessOccamSource :: String -> PassM [Token]
-preprocessOccamSource source = preprocessSource emptyMeta "<unknown>" source
+preprocessOccamSource source = preprocessSource emptyMeta [] "<unknown>" source