Beginning of the preprocessor

1 files changed, 94 insertions, 10 deletions

diff --git a/cpp.sml b/cpp.sml
index e2ffc2c..91f7f82 100644
--- a/cpp.sml
+++ b/cpp.sml
@@ -1,11 +1,95 @@
-fun main [fname] =
-let
-  val stream = Stream.streamInit fname
-  val tkl = Tokenizer.tokenize stream
-  val fileInfo = Stream.convert stream
-in
-  Tokenizer.printTokens tkl (#2 fileInfo)
-end
-  | main _  = printLn "Expected a signle argument: file name"
+structure Cpp:> CPP = struct
+  type tkPos = Stream.pos
+
+  type t =
+    { streams: Stream.t list, fileInfo: Stream.fileInfo list,
+      lastPos: tkPos option, firstId: Stream.fileId };
+
+  datatype tkExp =
+    Tk of Tokenizer.token |
+    Id |
+    NumConst |
+    StrLiteral |
+    UnOp |
+    BinOp |
+    Op
+
+  type tkExpectedValue = string * tkExp list
+
+  exception StreamTooOld
+  exception TkExpected of tkExpectedValue
+
+  fun create fname =
+  let
+    val stream = Stream.create fname
+    val info = Stream.convert stream
+  in
+   { streams = [stream] , fileInfo = [info], lastPos = NONE, firstId = #1 info }
+  end
 
-val () = main $ CommandLine.arguments ()
+  fun getToken
+    ({ streams = stream :: tail, fileInfo, lastPos, firstId }: t) =
+  let
+    val (tk, stream) = Tokenizer.getToken stream
+  in
+    case tk of
+      NONE => getToken { streams = tail, fileInfo, lastPos, firstId }
+    | SOME (pos, tk) =>
+        ( tk, { streams = stream :: tail, fileInfo,
+            lastPos = SOME pos, firstId })
+  end
+    | getToken
+        { streams = [], fileInfo, lastPos = SOME lastPos, firstId } =
+    let
+      val pos = SOME (#1 lastPos, ~1) (* EOF *)
+    in
+      (Tokenizer.EOS, {streams = [], fileInfo, lastPos = pos, firstId })
+    end
+    | getToken { streams = [], fileInfo, lastPos = NONE, firstId } =
+        (Tokenizer.EOS, { streams = [], fileInfo,
+            lastPos = SOME (firstId, ~1), firstId })
+
+  fun getLastPos ({ lastPos = NONE, ... }: t) = raise Unreachable
+    | getLastPos { lastPos = SOME p, ... } = p
+
+  val tkExp2str = fn
+      (Tk tk) => Tokenizer.token2str tk
+    | Id: tkExp => "identifier"
+    | NumConst => "numeric constant"
+    | StrLiteral => "string literal"
+    | UnOp => "unary operator"
+    | BinOp => "binary operator"
+    | Op => "operator"
+
+  fun prepAndRaise (stream: t) (id, pos) expList =
+  let
+    val fileInfo =
+      case List.find (fn (id', _, _) => id' = id) $ #fileInfo stream of
+        NONE => raise StreamTooOld
+      | SOME fileInfo => fileInfo
+    val pos = Stream.ppos2str $ Stream.pos2pposWithFI (id, pos) fileInfo
+  in
+    raise TkExpected (pos, expList)
+  end
+
+  fun tkExpectedPrint (pos, expList) =
+  let
+    fun tkExps2str [e] [] = tkExp2str e
+      | tkExps2str [e] acc =
+        (String.concatWith ", " acc ^ " or ") ^ tkExp2str e
+      | tkExps2str (e :: ec) acc =
+        tkExps2str ec (tkExp2str e :: acc)
+      | tkExps2str [] _ = raise Unreachable
+  in
+    print pos;
+    print ":expected ";
+    printLn $ tkExps2str expList []
+  end
+
+  fun debugPrint fname =
+  let
+    val stream = create fname
+  in
+    ()
+  end
+end