1 files changed, 39 insertions, 0 deletions
diff --git a/driver.fun b/driver.fun
new file mode 100644
index 0000000..78ca877
--- /dev/null
+++ b/driver.fun
@@ -0,0 +1,39 @@
+functor Driver(P: CPP): DRIVER = struct
+  structure P = P
+
+  type config = {
+    file: string option,
+    includeDirs: string list
+  }
+
+  val initConfig: config = { file = NONE, includeDirs = [] }
+
+  fun die msg = (printLn msg; Posix.Process.exit $ Word8.fromInt 1)
+
+  fun parseCmdArgs { file, includeDirs } [] =
+    if file = NONE then
+      die "missing input file"
+    else
+      { file, includeDirs = rev includeDirs }
+    | parseCmdArgs _ ("-I" :: []) =
+        die "-I: expected directory path after flag"
+    | parseCmdArgs { file, includeDirs } ("-I" :: path :: tail) =
+        parseCmdArgs { file, includeDirs = path :: includeDirs } tail
+    | parseCmdArgs { file, includeDirs } (arg :: tail) =
+      if String.sub (arg, 0) = #"-" then
+        die $ arg ^ ": unknown flag"
+      else
+        case file of
+          NONE => parseCmdArgs { file = SOME arg, includeDirs } tail
+        | SOME _ => die $ arg ^ ": file already specified"
+
+  fun exec () =
+  let
+    val config = parseCmdArgs initConfig (CommandLine.arguments ())
+
+    val cpp = P.create (valOf $ #file config) (#includeDirs config)
+  in
+    P.debugPrint cpp
+  end
+end
+