Implement FILE-STATUS

[pforth] / fth / file.fth

diff --git a/fth/file.fth b/fth/file.fth
index 6b0db20..0017942 100644 (file)
--- a/fth/file.fth
+++ b/fth/file.fth
@@ -68,7 +68,6 @@ create (LINE-TERMINATOR) \n c,
     WHILE                       ( )
         refill 0= IF EXIT THEN  ( )
     REPEAT
     WHILE                       ( )
         refill 0= IF EXIT THEN  ( )
     REPEAT

-

 ;
 
 }private
 ;
 
 }private


@@ -123,8 +122,23 @@ create (LINE-TERMINATOR) \n c,
     CASE
         -1 OF postpone ( ENDOF
         0  OF postpone ( ENDOF
     CASE
         -1 OF postpone ( ENDOF
         0  OF postpone ( ENDOF

+        \ for input from files

         multi-line-comment
     ENDCASE
 ; immediate
 
         multi-line-comment
     ENDCASE
 ; immediate
 

+\ We basically try to open the file in read-only mode.  That seems to
+\ be the best that we can do with ANSI C.  If we ever want to do
+\ something more sophisticated, like calling access(2), we must create
+\ a proper primitive.  (OTOH, portable programs can't assume much
+\ about FILE-STATUS and non-portable programs could create a custom
+\ function for access(2).)
+: FILE-STATUS ( c-addr u -- x ior )
+    r/o bin open-file           ( fileid ior1 )
+    ?dup
+    IF                          ( fileid ior1 )
+    ELSE close-file 0 swap      ( 0 ior2 )
+    THEN
+;
+

 privatize
 privatize