[slime-devel] presentations

[Matthias Koeppe]

Alan Ruttenberg <alanr-l at mumble.net> writes:

> Just wanted to point out that pretty printing isn't the only use
> case. It isn't the primary use in my work. 

I agree, but pretty printing is often enabled by default, and it is
not nice if the layout (for instance that of DESCRIBE) is messed up.

> Also, again, I haven't looked closely, but can the annotation
> approach you used solve this problem?

I use annotations to make presentations work within pretty printing
streams (of CMUCL, SBCL, and Allegro CL).  Unfortunately, annotations
do not help outside of pretty printing streams: Consider (LET
((*PRINT-PRETTY* T)) (FORMAT STREAM "~&~A ~A~%" OBJECT1 OBJECT2)).
Here two pp streams are created in sequence.  After OBJECT1 has been
printed, the pretty printing stream for OBJECT2 bases its layout
decisions on the character position of STREAM.  Presentation escape
sequences used for printing OBJECT1 will therefore influence the
layout of OBJECT2.  Unfortunately, at least in CMUCL and SBCL when
STREAM is a (built-in) Lisp stream, there is no way to influence the
character position, to correct it for the escape sequences.

-- 
Matthias Köppe -- http://www.math.uni-magdeburg.de/~mkoeppe