Block explorer upgraded to block editor!

blk/000

@@ -4,7 +4,7 @@ This is a Forth-style filesystems which is very simple. It is a
 list of 1024 bytes block, organised in 16 lines of 64 columns
 each. You refer to blocks by numbers. You show them with LIST.
 You interpret them with LOAD. For a convenient way to browse
-blocks, see Block Explorer at B100.
+blocks, see Block editor at B100.
 
 Conventions: When you see "(cont.)" at the bottom right of a
 block, it means that the next block continues the same kind of

blk/001

@@ -1,4 +1,4 @@
 MASTER INDEX
 
   3 Usage                      30 Dictionary
- 70 Implementation notes      100 Block explorer
+ 70 Implementation notes      100 Block editor

blk/100

@@ -1,10 +1,16 @@
-Block explorer
+Block editor
 
 This is an application to conveniently browse the contents of
-the disk blocks. You can launch it with "102 LOAD".
+the disk blocks and edit them. You can load it with "102 LOAD".
 
-USAGE: When loaded, the Forth interpreter is replaced by the
-explorer interpreter. Typing "Q" quits the program.
+Browse mode: If you execute BROWSE, the Forth interpreter is
+replaced by browser's loop. Typing "Q" quits the browser.
 
-Typing a decimal number followed by space or return lists the
-contents of that block. B for previous block, N for next.
+In this mode, typing a decimal number followed by space or
+return lists the contents of that block. B for previous block,
+N for next.
+
+When not in browse mode, your prompt is a regular Forth prompt
+with editor words loaded.
+
+                                                        (cont.)

blk/101

@@ -0,0 +1,2 @@
+T ( n -- ): select line n for editing.
+P xxx(return): put typed line on selected line.

blk/102

@@ -1,14 +1,13 @@
-103 LOAD
-VARIABLE _K
+103 LOAD 104 LOAD
 
-: PGM
+: BROWSE
     100 _LIST
     BEGIN
-        KEY
-        DUP 'Q' = IF DROP EXIT THEN
-        DUP 58 ( '9'+1 ) < IF _NUM
-        ELSE
-            _K ! _K (find) IF EXECUTE THEN
-        THEN
+        KEY CASE
+            'Q' OF DROP EXIT ENDOF
+            'B' OF B ENDOF
+            'N' OF N ENDOF
+            _NUM
+        ENDCASE
     AGAIN
-; PGM
+;

blk/103

@@ -5,5 +5,6 @@ VARIABLE ACC
     IF _LIST 0 THEN
     ACC !
 ;
-: B BLK> @ 1- DUP BLK> ! _LIST ;
-: N BLK> @ 1+ DUP BLK> ! _LIST ;
+: L BLK> @ _LIST ;
+: B BLK> @ 1- BLK> ! L ;
+: N BLK> @ 1+ BLK> ! L ;

blk/104

@@ -0,0 +1,13 @@
+( Line numbers for the user are 1-based, but in code, they're
+  0-based. )
+VARIABLE EDPOS
+: _bpos 64 * BLK( + ;
+: T 1- DUP EDPOS ! _bpos (print) CRLF ;
+: P
+    EDPOS @ _bpos C<
+    64 0 DO ( bpos c )
+        DUP 0xd = IF DROP 0 THEN
+        2DUP SWAP I + C!
+        DUP IF DROP C< THEN
+    LOOP
+;

forth/blk.fs

@@ -20,7 +20,7 @@
 ;
 
 : BLK@
-    DUP BLK> = IF DROP EXIT THEN
+    DUP BLK> @ = IF DROP EXIT THEN
     DUP BLK> ! BLK@* @ EXECUTE
 ;