I love this tip from Markus Triska, who attributes it to Ulrich Neumerkel: :- op(920,fy, *). *_. As a tool to isolate errors in code. But I don’t understand what the second specification is doing. After defining the unary operator, I would expect something like the following, to specify the sem…

[image] free-variation: After defining the unary operator, I would expect something like the following, to specify the semantics of the operator: *(_). So what does the line without parens do? Hi, As you’ve noted, the directive :- op(920, fy, *) defines * as an unary prefix operator. This…

Have you seen these, they might be of some help? “Declarative program development in Prolog” with GUPU by Ulrich Neumerkel and Stefan Kral ( PDF ) “Localizing and explaining reasons for non-terminating logic programs with failure-slices” by Ulrich Neumerkel and Fred Mesnard ( PDF ) While I am aware o…

[image] EricGT: On StackOverflow see user false (Ulrich) and tag failure-slice . I looked on StackOverflow for failure-slice by Ulrich but didn’t see anything for *_ – did I miss something? (The papers look interesting, but will take some work for me to understand)

This is where I saw the idea referenced: Debugging Prolog Programs Seems clever and useful. I’ve started using this mechanism, as it’s smoother than commenting out.

That’s a good article. It introduces the concept of generalisation and specialisation of a logic program, or a definite clause, that is central to Logic Programming and to Inductive Logic Programming (ILP). In fact all ILP approaches work on the basis of this concept: they either start with a progra…

[image] peter.ludemann: didn’t see anything for *_ See this for failure slicing: [false] Prolog successor notation yields incomplete result and infinite loop prolog, infinite-loop, failure-slice, successor-arithmetics answered by false on 12:51PM…

Help me understand this syntax: *_

General

jeshan March 24, 2024, 5:07am 9

See this for failure slicing:

also: program slicing - Selection sort in prolog - Stack Overflow

But specifically for *, it’s Triska’s video that explains the idea the best:

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Help me understand this syntax: *_

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