Implemented a search path for Tock (for #INCLUDE and #USE directives)

Main.hs

@@ -72,6 +72,7 @@ optionsNoWarnings =
   , Option ['c'] ["no-main"] (NoArg optNoMain) "file has no main process; do not link either"
   , Option ['o'] ["output"] (ReqArg optOutput "FILE") "output file (default \"-\")"
   , Option [] ["sanity-check"] (ReqArg optSanityCheck "SETTING") "internal sanity check (options: on, off)"
+  , Option ['I'] ["search-path"] (ReqArg optSearchPath "PATHS") "paths to search for #INCLUDE, #USE"
   , Option [] ["occam2-mobility"] (ReqArg optClassicOccamMobility "SETTING") "occam2 implicit mobility (EXPERIMENTAL) (options: on, off)"
   , Option [] ["usage-checking"] (ReqArg optUsageChecking "SETTING") "usage checking (options: on, off)"
   , Option [] ["unknown-stack-size"] (ReqArg optStackSize "BYTES")
@@ -118,6 +119,15 @@ optFrontend s ps
             _ -> dieIO (Nothing, "Unknown frontend: " ++ s)
           return $ ps { csFrontend = frontend }
 
+optSearchPath :: String -> OptFunc
+optSearchPath s ps = return $ ps { csSearchPath = csSearchPath ps ++ splitOnColons s }
+  where
+    splitOnColons :: String -> [String]
+    splitOnColons [] = []
+    splitOnColons s = case span (/= ':') s of
+      (p, _:more) -> p : splitOnColons more
+      (p, []) -> [p]
+
 optCompilerFlags :: String -> OptFunc
 optCompilerFlags flags ps = return $ ps { csCompilerFlags = flags ++ " " ++ csCompilerFlags ps}
 

data/CompState.hs

@@ -115,6 +115,7 @@ data CompState = CompState {
     csRunIndent :: Bool,
     csClassicOccamMobility :: Bool,
     csUnknownStackSize :: Int,
+    csSearchPath :: [String],
 
     -- Set by preprocessor
     csCurrentFile :: String, -- Also used by some later passes!
@@ -174,6 +175,7 @@ emptyState = CompState {
     csRunIndent = False,
     csClassicOccamMobility = False,
     csUnknownStackSize = 512,
+    csSearchPath = ["."],
 
     csCurrentFile = "none",
     csUsedFiles = Set.empty,

frontends/PreprocessOccam.hs

@@ -48,7 +48,8 @@ searchFile :: Meta -> String -> PassM (Handle, String)
 searchFile m filename
     =  do cs <- get
           let currentFile = csCurrentFile cs
-          let possibilities = [joinPath currentFile filename]
+          let possibilities = joinPath currentFile filename
+                              : [dir ++ "/" ++ filename | dir <- csSearchPath cs]
           openOneOf possibilities
   where
     openOneOf :: [String] -> PassM (Handle, String)