Snap for SWI-Prolog available

Announce
1

Thanks to the work of @LyzardKing there is now an official snap of SWI-Prolog available. Currently only in the beta and edge channel. Snaps provide an easy way for installing SWI-Prolog on a wide variety of Linux distributions.

Installing the snap

To install SWI-Prolog, simply run

snap install --beta swi-prolog

which provides two commands, the first being a console application and the second the Qt window version as developed by @CapelliC

swi-prolog.swipl
swi-prolog.swipl-win

You can get the usual command names from /snap/bin

snap alias swi-prolog.swipl swipl
snap alias swi-prolog.swipl-win swipl-win

Snaps have advantages and disadvantages. It should be easy enough to find details about that. The snap is probably the most convenient way for the casual user who wants a fairly up-to-date version and doesn’t like to go through the build process.

Font issue

There is a glidge in current snap infrastructure for handling the fontconfig library which is used by the xpce based IDE tools. You are a victim of if running ?- emacs. results in the error
below:

?- emacs.
[PCE fatal: @helvetica_roman_12/font: Xopen failed on @display/display
        in:     <No exception goal>
]
        [13] M @helvetica_roman_12/font ->_xopen(@display/display)
        [12] M @helvetica_roman_12/font ->_xopen(@display/display)
...

This can be resolved by cleaning the fontconfig global cache. Doing so has no consequences except for the first application to use fontconfig starting slow.

sudo rm /var/cache/fontconfig/*

Feedback

Please share your opinion/experience. If people are enthusiastic about this the snap based installation should get a prominent place on the download page.

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