after some discussion in IRC, we re-introduced a feature into PicoLisp
that had been there already once, in 2006/2007. It is called "transient
symbol markup", and changes how transient symbols are printed and edited
in a terminal window.
Now, per default, transient symbols are no longer surrounded by double
quotes, but are instead shown with _underlines_. The idea is to visually
emphasize the fact that these symbols are not strings. In addition,
pretty-printed functions and other structured data become more readable.
There is a new global variable '*Tsm', which holds two strings
(typically escape sequences) in a dotted pair. The CAR is sent to the
terminal (instead of the opening double quote) before the symbol name is
written, and the CDR after that (instead of the closing double quote).
With (off *Tsm) this behavior can be switched off, and the system will
accept and output transient symbols with plain double quotes as before.
When typing a transient symbol in the line editor, the double quote is
visible at the moment it is entered, but will be hidden after that.
While moving within a line (for example with the 'h' and 'l' commands)
the double quotes pop up whenever the cursor is in their neighborhood,
to make it easier to change them or to insert characters before or after
them, but disappear when the cursor moves away.
Armadillo (tc.rucho) is implementing support for transient symbol markup
also in his picolisp mode for 'emacs'. I would love to have it in 'vim'
too, but have no idea if or how this might be possible.