Scryer-prolog: Ctrl-c should interrupt get_single_char/1

Created on 5 May 2020 · 6Comments · Source: mthom/scryer-prolog

Currently, I get:

?- use_module(library(charsio)).
   true.
?- get_single_char(C).
(press Ctrl-c)
   C = c.

Expected: Interruption, yielding for example caught: error('$interrupt_thrown',repl).

Is it possible to implement this? One use case is interrupting animations of search processes, where get_single_char/1 is used for intermediate pausing.

Source

triska

Most helpful comment

Is it caught: error('$interrupt_thrown',repl)
or caught: error('$interrupt_thrown',get_single_char/1)?

The interrupt is caught by the REPL, typically.

mthom on 5 May 2020

👍2

All 6 comments

Another test case:

?- repeat, get_single_char(C), false.

Currently, it is not possible to interrupt this.

triska on 5 May 2020

Is it caught: error('$interrupt_thrown',repl)
or caught: error('$interrupt_thrown',get_single_char/1)?

notoria on 5 May 2020

Is it caught: error('$interrupt_thrown',repl)
or caught: error('$interrupt_thrown',get_single_char/1)?

The interrupt is caught by the REPL, typically.

mthom on 5 May 2020

👍2

I have an implementation but get_single_char/1 is the one throwing error. Will make a PR for this.

notoria on 5 May 2020

👍1

That would be perfect! Thank you a lot!

triska on 5 May 2020

👍1

Brilliantly resolved by @notoria in #460. Many thanks!

queens.pl now works very nicely, piping output to Ghostscript:

$ scryer-prolog -g 'show(20,[ff])' queens.pl | \
     gs -dNOPROMPT -g680x680 -dGraphicsAlphaBits=2 -r144 -q

Press any key to show the next solution. And now the animation can be nicely interrupted with Ctrl-c, followed by Ctrl-d to exit the Prolog process. Thank you again!

triska on 5 May 2020

👍1

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