12.-Entering-blocks-13-47.md

+## 12. Entering blocks 13 - 47
+
+For the moment we abandon the use of a blocks file. We could type in
+the listing as interactive input after metaforth's OK prompt. If we then
+make a mistake and mess up the system, we would be forced to start all
+over. Besides, this way we can only save a compiled system, not its
+source code.
+
+The solution to this is copy-paste. We type the listing into a normal
+ascii text file. We mark a chunk of it in our editor of choice, and do
+ctrl-c (for copy). Then we go to the OK prompt of the simulated forth
+system, and do ctrl-shift-v (for paste, we need to use shift because we
+are in a terminal). And look: we see metaforth eating
+(in fact compiling) our text as if it was being typed in by a monkey,
+saying OK after every carriage return. Solution found!
+
+We must be very grateful to the saints of software that this works. When
+it comes to accepting input, the hp2100 simulator is generally not so
+cooperative. It seems the debian version does not have libreadline
+compiled in. So you cannot recall your previous command by using uparrow
+and your only way of editing the current command is by using backspace.
+(This behaviour holds for the simulator command line, where nicer features
+could exist. That nice features do not exist inside simulated programs
+goes without saying. There we have to face the harshness of seventies
+computing anyway.)
+
+The pasted text is first accepted by the simulator. The simulator
+then feeds that text into its built-in simulated tty-terminal. This
+terminal is queried by the simulated tty-driver of metaforth, which
+then feeds the characters into its listen-for-input loop. In this
+chain many things can go wrong. The simulated terminal could differ
+from the real tty that was used. (Not very likely though, the
+tty interface is quite minimal.) We could have made a mistake
+while typing in the driver. The smallest error would have put
+us in a situation which is extremely hard to solve. But we have been
+lucky.
+
+Next page coming soon
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