Maxima: How to preserve prompt message to user (e.g. asksign()) when customizing output display?

user_3364065 0
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I'm developing an interface to Maxima (from R), that changes the output display of maxima on startup via an init-file:

load("mactex-utilities")$
load("alt-display.mac")$
set_prompt('prefix, "prompt;>>")$
set_prompt('suffix, "<<prompt;")$
my_display(x):=(?princ("out;>>"), ?princ("(%o"), ?princ(linenum), ?princ(") "), tex(?caddr(x)), ?princ("<<out;"))$
set_alt_display(2, my_display)$

Now I'm trying to handle cases were Maxima prompts the user to declare assumptions about variables like in this example:

(%i1) L: sqrt(1 - 1/(R^2));
                                          1
(%o1)                            sqrt(1 - --)
                                           2
                                          R
(%i2) integrate(x, x, 0, L);
Is R positive or negative?

positive;
                                     2
                                    R  - 1
(%o2)                               ------
                                        2
                                     2 R
(%i3)

So the default display shows a prompt message "Is R positive or negative?". However, when I use the initialization file above, this message does not get printed. However, the console waits for the user input. So my question is, if there is a way, so I can include it in my customized output. Preferably, I think it should be possible to also wrap it in pre-/suffix strings for my interface to properly catch it, but I'm not too versed with maxima internals.

Just for the record, my interface's repo is https://www.github.com/rcst/rmaxima

maxima
1 Answers

This topic has been resolved on the maxima mailing list (here)

In essence this seems to be a bug in the alt-display.lisp code

Thanks to Leo Butler, here is a re-written version of the initialization script that in addition customizes user prompt messages that circumvents the problem.

(load("mactex-utilities"), load("alt-display.mac"));
(set_prompt('prefix, "prompt;>>",'suffix, "<<prompt;"),
my_display(x):=block([type], type:?caar(x),
if type=?mtext then printf(true,"~%TEXT;>>~%~a~%<<TEXT;~%",?cadr(x))
else if type=?mlabel then printf(true,"~%out;>>~%(~a) ~a~a~a~%<<out;~%",?cadr(x),"$$",tex1(?caddr(x)),"$$")
else block([alt_display1d:false, alt_display2d:false], displa(x))),
set_alt_display(2,my_display)) $

When using this to initialize maxima, the output for the above example is

prompt;>>(%i1) <<prompt;L: sqrt(1 - 1/(R^2));

out;>>
(%o1) $$\sqrt{1-\frac{1}{R^2}}$$
<<out;
prompt;>>(%i2) <<prompt;integrate(x, x, 0, L);
prompt;>>
TEXT;>>Is R positive or negative?<<TEXT;
<<prompt;
p;

out;>>
(%o2) $$\frac{R^2-1}{2\,R^2}$$
<<out;
prompt;>>(%i3) <<prompt;
user_33640650
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