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I'm not mutable, I'm partially instantiated

blog.dnmfarrell.com

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Re: I'm not mutable, I'm partially instantiated

#61

Post by needlesslygrim »

harrisi wrote: post #50
coliveira wrote: post #40

Earlier quoted context omitted.

I always thought that pattern matching would be an excellent feature for other programming languages, but it seems that it hasn't become popular. Many strategies available to Prolog could become possible just by the addition of this feature. One possible implementation of the idea occurs with C++ templates specialized with numerical parameters. It also seems that Mathematica provides pattern matching, but I don't use…

Erlang, Elixir, Swift, Rust, Python, probably some others. That list is roughly in order of how capable and useful the pattern matching is in each of those languages. Erlang was originally written in Prolog. Also, I definitely agree it's a feature I miss everywhere when not using Erlang/Elixir.

I'm curious, how does Swift have better pattern matching than Rust?

Re: I'm not mutable, I'm partially instantiated

#62

Post by sulam »

needlesslygrim wrote: post #61
harrisi wrote: post #50

Earlier quoted context omitted.

Erlang, Elixir, Swift, Rust, Python, probably some others. That list is roughly in order of how capable and useful the pattern matching is in each of those languages. Erlang was originally written in Prolog. Also, I definitely agree it's a feature I miss everywhere when not using Erlang/Elixir.

I'm curious, how does Swift have better pattern matching than Rust?

These are probably tied TBH.

Re: I'm not mutable, I'm partially instantiated

#63

Post by lordwarnut »

lynx23 wrote: post #38
openasocket wrote: post #17

I've never used it in production, but I have a deep love of Prolog, just because of how different it is from any other programming language I've used. As a programming paradigm, it found it as eye-opening as functional programming. What I found interesting is that you are operating on logical statements and pattern matching, which often means that the same "function" can be used for multiple different things. For exa…

Do you have a suggestion on where to / how to start learning Prolog beyond towers-of-hanoi? Prolog is basically the last language on my list of things I want to look at, but whenever I tried, I failed to find anything practical to do/try.

I have been going through https://www.ic.unicamp.br/~meidanis/courses/mc336/2009s2/pro...

It starts out pretty easy but gets harder and requires more thought. It has different sections on things like list processing or graph problems.

Re: I'm not mutable, I'm partially instantiated

#64

Post by jfmc »

coliveira wrote: post #37
wizzwizz4 wrote: post #20

Earlier quoted context omitted.

It doesn't scale that well because integers are their own, opaque thing in Prolog, and the is predicate is unidirectional. However, there's no inherent reason this has to be the case: you can construct your own representation of the integers from the Peano axioms, and recover bidirectionality of addition. (You'll want to be using some typed variant of Prolog with the "unary tree of units" optimisation, otherwise inte…

Modern Prolog libraries have handled the issues of unidirectional integer predicates, so the old ways of handling numeric values is not relevant for most problems.

Many times the algorithm that you are implementing requires a precise data flow that is not reversible, so using traditional arithmetic (is/2) is better for catching errors.

On the other hand CLP(FD) is not new at all (it is very popular for constraint programming).

Re: I'm not mutable, I'm partially instantiated

#65

Post by rscho »

iamwil wrote: post #58
mananaysiempre wrote: post #41

Earlier quoted context omitted.

Matching of patterns , with only a single occurrence allowed for each variable, is fairly popular in languages designed in the last two decades, isn’t it? A lot of those have or at least borrow from ML heritage, and that of course places a big emphasis on algebraic types and pattern matching. Full-blown unification remains niche, that’s true, but it’s just a fairly heavyweight feature, and I don’t really know how you…

Simon Peyton Jones (of Haskell) is working on Verse, a functional relational programming language, that merges the ideas of both functional and logical programming into one. It’s being done to facilitate Fortnite metaverse, as he’s doing this work at Epic. https://youtu.be/OJv8rFap0Nw?si=OmBT9CBJIxdJE1Jv

Functional logic programming much before Verse https://mercurylang.org/

Re: I'm not mutable, I'm partially instantiated

#66

Post by rscho »

jfmc wrote: post #64
coliveira wrote: post #37

Earlier quoted context omitted.

Modern Prolog libraries have handled the issues of unidirectional integer predicates, so the old ways of handling numeric values is not relevant for most problems.

Many times the algorithm that you are implementing requires a precise data flow that is not reversible, so using traditional arithmetic (is/2) is better for catching errors. On the other hand CLP(FD) is not new at all (it is very popular for constraint programming).

Why would it be better for error handling? If you'll be using unidirectional flow only, then the point is moot. But using clp is arguably better IMO, allowing type and range checks while allowing relational execution.

Re: I'm not mutable, I'm partially instantiated

#67

Post by rscho »

ks2048 wrote: post #48

Is "The Art of Prolog" a good place to start with the lanugage?

The book is ok for core Prolog, but quite old and many new features have been made available since then. Including stuff making parts of the core language obsolete.

Honestly, the language is super small. Best way to learn IMO is to go on https://swish.swi-prolog.org/ and do the examples / play with it. If you stick to it, then you can branch to other engines later (there are many systems with unique features).

Re: I'm not mutable, I'm partially instantiated

#68

Post by [deleted] »

openasocket wrote: post #17

I've never used it in production, but I have a deep love of Prolog, just because of how different it is from any other programming language I've used. As a programming paradigm, it found it as eye-opening as functional programming. What I found interesting is that you are operating on logical statements and pattern matching, which often means that the same "function" can be used for multiple different things. For exa…

[deleted]
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