--- camlp4/meta/pa_macro.ml	29 Oct 2003 22:04:22 -0000
+++ camlp4/meta/pa_macro.ml	29 Oct 2003 22:42:01 -0000
@@ -16,8 +16,8 @@
 
   In expressions:
 
-     IFDEF <uident> THEN <expression> ELSE <expression> ENDIF
-     IFNDEF <uident> THEN <expression> ELSE <expression> ENDIF
+     IFDEF <uident> THEN <expression> [ ELSE <expression> ] ENDIF
+     IFNDEF <uident> THEN <expression> [ ELSE <expression> ] ENDIF
      __FILE__
      __LOCATION__
 
@@ -30,12 +30,18 @@
 
      -D<uident>
      -U<uident>
+     -I<dir>
 
   After having used a DEFINE <uident> followed by "= <expression>", you
   can use it in expressions *and* in patterns. If the expression defining
   the macro cannot be used as a pattern, there is an error message if
   it is used in a pattern.
 
+  INCLUDE can be used to include a file with a number of macro definitions;
+  however it can not have any non-macro toplevel items. The INCLUDE files
+  are looked up in directories passed in via the -I option, falling back to
+  current directory.
+
   The expression __FILE__ returns the current compiled file name.
   The expression __LOCATION__ returns the current location of itself.
 
@@ -50,7 +56,8 @@
   [ SdStr of 'a
   | SdDef of string and option (list string * MLast.expr)
   | SdUnd of string
-  | SdITE of string and list (item_or_def 'a) and list (item_or_def 'a) ]
+  | SdITE of string and list (item_or_def 'a) and list (item_or_def 'a)
+  | SdInc of string ]
 ;
 
 value rec list_remove x =
@@ -185,12 +192,45 @@
   [ Not_found -> () ]
 ;
 
+(* This is a list of directories to search for INCLUDE statements. *)
+value include_dirs = ref []
+;
+
+(* Add something to the above, make sure it ends with a slash. *)
+value add_include_dir str =
+  if str <> "" then
+    let str =
+      if String.get str ((String.length str)-1) = '/'
+      then str else str ^ "/"
+    in include_dirs.val := include_dirs.val @ [str]
+  else ()
+;
+
+value smlist = Grammar.Entry.create Pcaml.gram "smlist"
+;
+
+value parse_include_file =
+  let dir_ok file dir = Sys.file_exists (dir ^ file) in
+  fun file ->
+    let file =
+      try (List.find (dir_ok file) (include_dirs.val @ ["./"])) ^ file
+      with [ Not_found -> file ]
+    in
+    let st = Stream.of_channel (open_in file) in
+    let old_input = Pcaml.input_file.val in
+    do {
+      Pcaml.input_file.val := file;
+      let items = Grammar.Entry.parse smlist st in
+      do { Pcaml.input_file.val := old_input; items } }
+;
+
 value rec execute_macro = fun
 [ SdStr i -> [i]
 | SdDef x eo -> do { define eo x; [] }
 | SdUnd x -> do { undef x; [] }
 | SdITE i l1 l2 ->
-   execute_macro_list (if is_defined i then l1 else l2) ]
+   execute_macro_list (if is_defined i then l1 else l2)
+| SdInc f -> execute_macro_list (parse_include_file f) ]
 
 and execute_macro_list = fun
 [ [] -> []
@@ -201,7 +241,7 @@
 ; 
 
 EXTEND
-  GLOBAL: expr patt str_item sig_item;
+  GLOBAL: expr patt str_item sig_item smlist;
   str_item: FIRST
     [ [ x = macro_def ->
          match execute_macro x with
@@ -220,7 +260,8 @@
           SdITE i [] dl
       | "IFNDEF"; i = uident; "THEN"; dl1 = smlist; "ELSE";
         dl2 = smlist; "ENDIF" ->
-          SdITE i dl2 dl1 ] ]
+          SdITE i dl2 dl1
+      | "INCLUDE"; file = STRING -> SdInc file ] ]
   ;
   smlist:
     [ [ sml = LIST1 str_item_or_macro -> sml ] ]
@@ -267,4 +308,7 @@
 ;
 Pcaml.add_option "-U" (Arg.String undef)
   "<string> Undefine for IFDEF instruction."
+;
+Pcaml.add_option "-I" (Arg.String add_include_dir)
+  "<string> Add a directory to INCLUDE search path."
 ;