VE: add backspace support in replace mode

blk/130

@@ -4,7 +4,8 @@
     SWAP _cpos FBUF ( len src dst ) ROT MOVE ;
 : $R ( replace mode )
     mode! 'R' EMIT
-    BEGIN setpos KEY DUP 0x20 >= IF
+    BEGIN setpos KEY DUP BS? IF -1 EDPOS +! DROP 0 THEN
+        DUP 0x20 >= IF
         DUP EMIT EDPOS @ _cpos C! 1 EDPOS +! BLK!! 0
     THEN UNTIL mode! SPC contents ;
 : $O EDPOS @ 0x3c0 ( 15 * 64 ) >= IF EXIT THEN
@@ -13,4 +14,3 @@
 : $D $H 64 icpy
     acc@ 0 DO 16 EDPOS @ 64 / DO i _mvln- LOOP LOOP
     BLK!! contents ;
-

blk/378

@@ -12,3 +12,5 @@
 
 
 
+
+

blk/387

@@ -1,16 +1,16 @@
 ( handle backspace: go back one char in IN>, if possible, then
   emit BS + SPC + BS )
-: (inbs)
+: _bs
     ( already at IN( ? )
     IN> @ IN( = IF EXIT THEN
     IN> @ 1- IN> !
     BS SPC BS
 ;
+( del is same as backspace )
+: BS? DUP 0x7f = SWAP 0x8 = OR ;
 
 : KEY
     85 RAM+ @ ( (key) override )
     ?DUP IF EXECUTE ELSE (key) THEN ;
-
-
 ( cont.: read one char into input buffer and returns whether we
   should continue, that is, whether CR was not met. )

blk/388

@@ -1,10 +1,9 @@
 : (rdlnc) ( -- c )
     ( buffer overflow? same as if we typed a newline )
     IN> @ IN) = IF 0x0a ELSE KEY THEN ( c )
-    DUP 0x7f = IF DROP 0x8 THEN ( del? same as backspace )
     DUP 0x0a = IF DROP 0xd THEN ( lf? same as cr )
     ( bacspace? handle and exit )
-    DUP 0x8 = IF (inbs) EXIT THEN
+    DUP BS? IF _bs EXIT THEN
     ( echo back )
     DUP EMIT ( c )
     ( write and advance )