allow dollar sign as another variant of ^[ (discard all arguments or return)

 * some classic TECOs have this
 * just like ^[, dollar works as a command only, not as a string terminator
 * it improves the readability of macros using printable characters only
 * it closes a gap in the language by allowing $$ (double-dollar) and
   ^[$ as printable ways to write the return from macro command.
   ^[^[ was not and is not possible.
 * since command line termination is a regular interactive return-command
   in SciTECO, double-dollar will also terminate the command line now.
   This will be allowed unless it turns out to be a cause of trouble.
 * The handling of unterminated commands has been cleaned up by
   introducing State::end_of_macro().
   Most commands (and thus states) except the start state cannot be
   valid at the end of a macro since this indicates an unterminated/incomplete
   command.
   All lookahead-commands (currently only ^[) will end implicitly
   at the end of a macro and so will need a way to perform their action.
   The virtual method allows these actions to be defined with the rest
   of the state's implementation.

1 files changed, 11 insertions, 1 deletions

diff --git a/TODO b/TODO
index d9418a6..390c6c5 100644
--- a/TODO
+++ b/TODO
@@ -160,10 +160,20 @@ Features:
    between effective and rubbed out command line - without
    resetting it. This would add another alternative to { and }
    for fixing up a command line.
- * some missing useful VideoTECO/TECO-11 commands:
+ * some missing useful VideoTECO/TECO-11 commands and unnecessary
+   incompatibilities:
    * EF with buffer id
    * ER command: read file into current buffer at dot
    * nEW to save a buffer by id
+   * EI is used to open an indirect macro file in classic TECO.
+     EM should thus be renamed EI.
+     EM (position magtape in classic TECO) would be free again,
+     e.g. for execute macro with string argument or as a special version
+     of EI that considers $SCITECOPATH.
+     Current use of EI (insert without string building) will have
+     to move, e.g. to FI.
+   * ^S (-(length) of last referenced string), ^Y as .+^S,.
+   * ^Q convert line arg into character arg
    * ^A and stdio in general
  * Buffer ids should be "circular", i.e. interpreted modulo the
    number of buffers in the ring. This allows "%*" to wrap at the