There is one button in the gui tracer that doesn’t do anything.
Its the button with the label “Enter a query (in new thread) (B)”.
I am using Swipl 9.3.30, on Linux Mint 22.1.
This button used to work. I am not sure, but I think it stopped working when I upgraded Linux to Linux Mint Cinnamon 22.1.
Thanks for reporting. library(threadutil) needs to be cleaned. Note that if you run from swipl-win, you can split the console using Shift-Ctrl-O.
In the new setup, I tend to run swipl-win arg ... rather than swipl arg ... for interactive usage. The options are the same. The swipl-win creates an Epilog console that is a fairly decent terminal that provides some menu actions, can be split and turns messages linked to a source location into clickable links.
$ swipl-win
swipl-win: command not found
$
I don’t have “swipl-win”.
But I can start the Swi console using a command like “/usr/bin/flatpack …”.
Jan wrote:
Note that if you run from
swipl-win, you can split the console using Shift-Ctrl-O.”.
That looks really useful.
Is there also a key to unsplit the console?
Did it not install the GUI? Traditionally, that is a package called swi-prolog-x, I think. It may not be there yet though as it depends on SDL3 and this library is not yet mainstream. Only the latest version of a couple of pretty up-to-date distributions have it. If it installed the gui and the command is still missing, this should be fixed. You can check by running
?- epilog.
Otherwise, swipl-win is the same as swipl -Depilog
Just enter Ctrl-D for end-of-file.
I have epilog, but I can’t start it with “$ swipl-win”.
$ swipl -Depilog
swipl: Usage:
…
That is an old version of Swipl, its 9.0.4 . I recently installed a newer version of Swipl from the Software Manager, a flatpack. I think it was version 9.3.29 initially. I later updated it to version 9.3.30.
This newer version can be started from the Start Menu, its starts the prolog console.
I didn’t uninstall the old version of Swipl first, so the command “$ swipl” still starts up version 9.0.4.
By looking at the Linux menu, the menu similar to what Microsoft calls the “Start Menu”, I can see that when I start Swi Prolog from the menu, it runs this linux command:
/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=swipl-win --file-forwarding org.swi_prolog.swipl @@u %U @@
So I can start epilog from the menu, or by typing that command into the Linux Terminal.
Once I have started Swi prolog from the menu, i.e. the prolog console, if I enter “?- epilog.” then it opens an identical window.
I don’t know why “$ swipl-win” doesn’t work.
About splitting windows in the prolog console, epilog. I have just discovered that when I right-click in the Swi console window, its shows a menu, that I can use to split the window, and to unsplit it by closing one of the sub-windows. This menu is good, its easy to understand. But not easy to find.
Because the binaries in /usr/bin are old. You can run both swipl-win and swipl using flatpak using the --comand= option. That recognizes both swipl and swipl-win. Eventually, Linux will get updated, but before this happens for most distros we need to release stable 9.4.0 and the distro needs to provide the SDL3 dependency. For short, that may take a while 
Before than, the flatpak or compiling from source are your only options.
Pushed several fixes that replace the xterm, Qt or Windows-code implementation for this by the new xpce based Epilog Prolog console. These patches also remove the old interfaces from the source code.