Questions tagged [prolog]
Prolog is the most commonly used logic programming language. It supports non-deterministic programming through backtracking and pattern matching through unification.
40
questions
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20 views
Prolog destructor?
I have an init predicate which asserts some facts. I would like to clean these up after execution.
I'm running queries of the form init, do_stuff, cleanup.. I would ...
2
votes
0answers
27 views
Pocket cube solver in Prolog
Hello I have writtern this Prolog code to solve a scrambled 2x2 rubiks cube. Also known as a a pocket cube.
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vote
1answer
33 views
Prolog refactor if/else
How do I refactor this mess of if/else conditions so that it's more readable?
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2
votes
0answers
22 views
Simple task with recursion on Prolog
I'm new in Prolog. So, I'm not sure if my code is ok and optimized. I'm also not sure if I use recursion correctly.
Task: find students that has at least 1 bad grade (1 or 2) and print them in table
...
6
votes
1answer
199 views
Constraint solving CrossCells puzzle game solution
There's a puzzle game called
CrossCells (not
affiliated; there's also multiple other ones with the same kind of idea,
but slightly different layout and rule set) that I've been playing on
and off. ...
3
votes
0answers
55 views
Basic logic problem in Prolog
I thought it would be a good idea to take some easy to solve (by hand) problems and model them in Prolog for practice. Here is a problem I modeled in Prolog:
A messy kid wrote a multiplication ...
3
votes
0answers
117 views
Writing a tokenizer in SWI-Prolog
To teach myself how to do meta-progaming using Prolog, I've been playing around with translating ABNF syntax into DCG syntax. I'm still at the lexing and tokenising stage, but hope to advance to the "...
1
vote
2answers
83 views
Find CISC prerequisites
Below I have some code written in prolog as a brief example. The goal of the program is to take a Computer and Information Science (CISC) course number and return any CISC prerequisites (prereqs).
I ...
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vote
0answers
92 views
Echo in Prolog with single print (new version)
In order to learn a bit more of Prolog, I implemented the echo command for SWI-Prolog.
I want a correct implementation, that is, it satisfies the following requirements:
It makes only one I/O call ...
2
votes
1answer
354 views
Echo in prolog with single print
In order to learn a bit more of Prolog, I implemented the echo command for SWI-Prolog.
I want a correct implementation, that is, it satisfies the following ...
5
votes
1answer
130 views
Counting number of seen states
I have some code which executes a simple task, counting the number of states reachable from a particular state, would just like some advice on how to improve it.
So far it stores all the states it ...
4
votes
2answers
869 views
Zebra puzzle in Prolog
I have attempted to a zebra puzzle in prolog and I was seeking some feedback as to the way I went about solving the puzzle.
Here is the puzzle:
Two weeks ago, four enthusiasts made sightings of ...
2
votes
0answers
125 views
All outcomes for subtraction on each value in list individually
As you can see from my predicate iterate, I am repeating Z is X-3 and Z is X-2, the scenarios are different if the value is 0 or ...
4
votes
1answer
15k views
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1answer
523 views
Harry Potter's Family Tree Database
As an assignment for a class, I have made a small Harry Potter family tree in Prolog. It compiles into a self-contained executable that can be run straight from the command line on Linux machines. ...
3
votes
0answers
200 views
Movie Knowledgebase
I have had an assignment to construct a movie knowledgebase and ten specified queries in Prolog. This is my first ever Prolog program, so I would appreciate any pointers toward how I could improve.
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3
votes
2answers
144 views
CLP(FD) labeling on possibly infinite domains
As a follow-up to this SO question, I implemented, for my Prolog-based language Brachylog, my own labeling predicate brachylog_equals/2 which is not guaranteed to ...
4
votes
1answer
402 views
Aggregate cost for a directed graph in Prolog
I've come up with a simple graph traversal algorithm to calculate the aggregated cost of a directed graph or its subgraphs. Given a directed graph, the code visits all reachable nodes and sums up the ...
6
votes
1answer
217 views
Logic Prolog compiler
I'm actually doing my own Prolog compiler just like SWISH one with Java. Prolog is a logic language that is particularly suited to programs that involve symbolic or non-numeric computation. Prolog ...
7
votes
3answers
753 views
Prolog parser written in Haskell
I am writing a very simple Prolog intepreter in Haskell. It's a class assignment and I really want to do it right.
I was able to (quite quickly) write a parser for the language. Today I borrowed a ...
3
votes
1answer
78 views
Prolog predicate for adjacency of integers with all signatures and no spurious choice points
I want to create a predicate nearby(X,Y) which represents "X and Y are integers 1 apart from each other" and fully satisfies:
...
3
votes
0answers
13k views
Monkey-banana problem in Prolog
The monkey-banana problem: There many variations to this problem, but the basic premise is that a monkey is in a room with a banana and
a chair, and the monkey cannot reach the banana until he moves ...
10
votes
1answer
499 views
cat program in Prolog
In order to learn Prolog, I have implemented the cat command in Prolog. I want to know if the code is idiomatic and what could be improved.
File ...
2
votes
0answers
29 views
meta predicates fixedpoint/3 and fixedpointlist/3
What about the following meta-predicate "fixed point"?
...
5
votes
1answer
242 views
map + foldl = mapfoldl
I was wondering... In the standard library of some Prolog systems, there are meta-predicates like maplist and foldl.
In general,...
7
votes
2answers
542 views
Higher-order Prolog predicates combine/3 and reduce/3
I'm trying to find useful versatile meta-predicates that are different from the vanilla ones offered currently by library(apply).
How about the following two: <...
4
votes
1answer
111 views
SICP Exercise 1.3: Sum of squares of two largest numbers out of three, Prolog Version
The exercise 1.3 of the book Structure and Interpretation of Computer Programs asks the following:
Exercise 1.3. Define a procedure that takes three numbers as arguments and returns the sum of the ...
2
votes
1answer
92 views
Repeated string concatenation
I've been looking for a way to have a predicate that establishes that all elements of a list are substrings delimited by a given string. Analogues in other languages include: ...
2
votes
1answer
584 views
Adding elements in two lists as numbers
The problem is adding two lists as numbers L1 = [1,9,9] and L2 = [0,9,9]:
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5
votes
1answer
166 views
Binary Digits to ASCII Characters
I wrote this code, as a novice a to Prolog, for a challenge posted on /r/DailyProgrammer. The formal description of this challenge, as presented in the prompt reads:
Input description
On ...
2
votes
1answer
126 views
English phrases, prime numbers, pseudo random data and encryption source code check
This code uses a DCG and pairs phrases into near-English sentences. If anyone is familiar with Prolog, I'm wondering how I can use the code as an encryption method by hiding data and replacing it ...
2
votes
2answers
78 views
Iterating towards a goal
I'm pretty proud of the following, but would welcome any comments from experts:
...
2
votes
1answer
274 views
Implementing an open/close function in Prolog
I'm going through the Adventure in Prolog tutorial and I'm trying to implement an open/close rule for each of the doors I have.
Add an open/closed status for each of the doors. Write open and close ...
9
votes
1answer
9k views
“Hello world!” in Prolog
I have just written the following "hello world" program in Prolog. Although it is as simple as it can be, I would like your feedback as Prolog is very new to me.
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6
votes
1answer
120 views
Sample n items without replacement in Prolog
I have the following Prolog code which samples n items from a list without replacement:
...
4
votes
1answer
84 views
Implementing a zipwithindex predicate in prolog
I want to implement a predicate of the form:
zipwithindex(?List1, ?List2)
which is true when the elements of List2 are the ...
4
votes
2answers
3k views
Prolog Sudoku solver taking too long
I was wondering if there's any way I can improve this code's execution. I want to use it on a 9*9 grid, but it takes too long to solve this as 4*4. This program takes as input a 4*4 matrix ...
5
votes
1answer
1k views
Complete graph traversal algorithm in Prolog
Given a table, I want to explore all possible transition between the elements in the table.
ex: for a table with size 3 [0,1,2], the output of the algorithm should be 0->1, 1->0, 0->2, 2->1, 1->2, 2->...
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vote
2answers
2k views
Range of all variables in List in Prolog
I have a list in Prolog like this:
Puzzle = [ A1, A2, A3,
B1, B2, B3,
C1, C2, C3 ].
And I want every variable in the list to be a number ...
1
vote
1answer
323 views
Bibtex reader using Prolog
I am trying to learn Prolog, and wrote a bibtex reader using GNU Prolog.
I would like some feedback on my code in terms of: the way I write Prolog, and how it can be improved.
Gist
...
