Is substitution implemented in the Haskell backend? - kframework

I've been using the Java backend for symbolic execution because it has substitution (e.g. E[V/X]). Is substitution implemented in the Haskell backend?

As of July 2020, the answer is no.

Related

using different programming language in godot game engine?

I want to bind a different programming language to the Godot game engine. Is there an instructional document or video on this topic? For example, how was this project done: godot-rust. If I can learn the basics, I can succeed in working in a different language. Thanks.
In this answer I show you the different approaches to add language support in Godot 3.x (the situation will be somewhat different with Godot 4.0 and GDExtension - which replaces GDNative and hopefully means less custom builds), and I mention some languages that are supported by each of these approaches. However, this is not an exhaustive list of the languages.
First of all, Godot has official build-in support for GDScript and Godot's VisualScript (and Godot's shading language and its visual counterpart if those counts for you).
There are a few ways to use C++:
You can use it to create GDNative scripts (which are basically a wrapper around native calls that allow you to use them as scripts in Godot).
Or you can create modules (which are static libraries you can add in a custom Godot build).
And since Godot source is in C++, you don't have to restrict yourself to making modules if you are making custom builds.
In web builds Godot can interface with JavaScript via the JavaScript class. However, this approach does not allow you to add JavaScript scripts to Nodes, and so on.
Then there are languages that can only be added in custom builds of Godot, which is currently the official support for C#.
There are other non-official custom builds that offer language binding for languages such as Lua, Kotlin, TypeScript and JavaScript (this time allowing you to make scripts).
If you need to add a runtime, you would probably do this.
Some language take advantage of the fact that Godot's has official Mono support in order to support C#. This way you can, for example, use F# and Clojure.
They start by adding a C# project and then modify it so it uses another language. This is viable if your language already compiles to .NET.
Some other languages can be added as plugins that implement the PluginScript class via GDNative. This is the case of Python and Lua (again) which you can get from the asset library.
This is the most user friendly way to add language support to Godot, but it is limited to what you can do with PluginScript.
Addendum: Gil Barbosa Reis, author of the aforementioned Lua bindings, has an article series about its implementation stuffed away in the repository (in English and Portugueses): godot-lua-pluginscript/extras/articles/. It is probably the most comprehensive tutorial to date.
Other languages are added by means of taking advantage of GDNative (They basically mimic what you would do with C++). This is the case of Nim, Rust, D, Haskell, Go, Swift…
So that's how godot-rust works: make native libraries using rust and the godot-rust create and add them as if they were made in C++. For any language for which there are the means to make native libraries already, this is a good option.
Finally there is another way to add support for a language: a transpiler from that language to GDScript, which can be automated with an addon that might also be written in GDScript. This is the case of Lisp.
This last approach is mostly used for domain specific languages.
The official docs here provide your answer:
Godot officially supports GDScript, C/C++, C#.
Some 3rd party languages that can be used are: Rust, D, Python, Nim, and Go.

What replaces the MVC pattern in functional programming?

I'm a MVC web developer who's become very interested in functional programming to write web apps (specifically, I'm captivated by Erlang and Cowboy.)
What I'm having trouble finding an answer to/resources on is what pattern is used to replace MVC in FP.
Obviously the idea of an ORM is ludicrous in FP, since it's not object oriented, so what is used to replace it for persistence logic? Is it usual to just build a module that uses a library to create functions that interface with the datastore, or are there tools similar to ORMs?
Both advice and links to resources would be greatly appreciated. Bonus points for Erlang/Cowboy specific help. Thanks.
There are MVC frameworks for Erlang. It's ChicagoBoss for example.
Quoting from an article by #yarivs:
Erlang does carry its weight in all letters of the MVC. For the Model, forget database abstraction layers: you have a pure Erlang distributed database called Mnesia. For the view, Yaws has ehtml. For the controller, Yaws has appmods and Erlang's pattern matching.
I hope this helps.
im a coder for erlang. i use erlang for my web-game server...
so...there is no View..and in function luangues this is no Model...
so from my point of view, function luangues there is no need of MVC
(just like no class or subclasses in function luangues..)
Lift framework(written in Scala) uses pattern called 'view first'.
follow link https://www.assembla.com/wiki/show/liftweb/View_First

Is there a version of Smalltalk with Erlang style distributed message passing?

Is there a version of Smalltalk that allows distributed message passing, much as Erlang has? Could Smalltalk be an ideal language if it has this distributed message passing, as Smalltalk also implements its own VM if I am not mistaken?
Everything in Smalltalk is done through message passing. Almost all of it is local of course.
Richard Durr hints at it in his answer, but Croquet have a library called Islands, which is modelled on E's Vats.
Have a look at Croquet. Maybe their technology is what you want.
http://en.wikipedia.org/wiki/Croquet_project
There is SqueakElib
http://www.squeaksource.com/squeakelib.html
wiki.squeak.org/squeak/6011
In Cincom VisualWorks there is a library called OpenTalk. The basic idea is the same -- replace remote object with local proxy. Good thing about OpenTalk is that in many cases it just works, and in other cases you can customize it by replacing its components (marshaller, policies, network transport, etc).
Basically, OpenTalk message passing is synchronous (contrary to Erlang as far as I know). But you can implement (and some users have implemented) any required semantics in a rather straightforward way.
OpenTalk is a part of standard VisualWorks library.
VisualWorks page at Cincom:
http://www.cincomsmalltalk.com/main/products/visualworks

calculus engine in vb?

is there an easy to use library or engine for .NET that does calculus?
I posted an early version of some code I used in one of my classes in an answer to this thread:
Generated methods for polynomial evaluation (my answer includes classes for symbolic differentiation)
If I know exactly what you're looking for, I could try to post an updated version.
Google is suggesting you look through Wikipedia's list of free libraries that can do automatic differentiation, and see if any have a .NET or COM wrapper. EDIT: High-Performance Mark has pointed out that it appears you need symbolic differentiation, in which case these libraries won't help.
If you are keen, you possibly could create a .NET wrapper for one of the C++ libraries.

Which environment, IDE or interpreter to put in practice Scheme?

I've been making my way through The Little Schemer and I was wondering what environment, IDE or interpreter would be best to use in order to test any of the Scheme code I jot down for myself.
Racket (formerly Dr Scheme) has a nice editor, several different Scheme dialects, an attempt at visual debugging, lots of libraries, and can run on most platforms. It even has some modes specifically geared around learning the language.
I would highly recommend both Chicken and Gauche for scheme.
PLT Scheme (DrScheme) is one of the best IDEs out there, especially for Scheme. The package you get when downloading it contains all you need for developing Scheme code - libraries, documentation, examples, and so on. Highly recommended.
If you just want to test your scheme code, I would recommend PLT Scheme. It offers a very complete environment, with debugger, help, etc., and works on most platforms.
But if you also want to get an idea of how the interpreter behind the scenes works, and have Visual Studio, I would recommend Tachy. It is a very lightweight scheme interpreter written in c#. It allows you to debug just your scheme code, or also step through the c# interpreter behind the scenes to see what is going on.
Just for the record I have to mention IronScheme.
IronScheme will aim to be a R6RS conforming Scheme implementation based on the Microsoft DLR.
Version 1.0 Beta 1 was just released. I think this should be good implementation for someone that is already using .NET framework.
EDIT
Current version is 1.0 RC 1 from Oct 23 2009
Google for the book's authors (Daniel Friedman and Matthias Felleisen). See whether either of them is involved with a popular, free, existing Scheme implementation.
It doesn't matter, as long as you subscribe to the mailing list(wiki/irc/online-community-site) for the associated community. It's probably worth taking a look at the list description and archives to be sure you are in the right one.
Most of these are friendly and welcoming to newcomers, so don't be afraid to ask.
It's also worth searching the archives of their mailing list(or FAQ or whatever they use) when you have a question - just in case it is a frequent question.
Good Luck!
Guile running under Geiser within Emacs provides a nice, lightweight implementation for doing the exercises. Racket will also run under Geiser and Emacs, though I personally prefer Guile and Chez Scheme a bit more.
Obviously installation of each will depend on your OS. I would recommend using Emacs version 24 and later since this allows you to use Melpa or Marmalade to install Geiser and other Emacs extensions.
The current version of Geiser also works quite nicely with Chicken Scheme, Chez Scheme, MIT Scheme and Chibi Scheme.
LispMe works on a Palm Pilot, take it anywhere, and scheme on the go. GREAT way to learn scheme.
I've used PLT as mentioned in some of the other posts and it works quite nicely. One that I have read about but have not used is Allegro Common LISP Express. I read a stellar review about their database app called Allegro Cache and found that they are heavy into LISP. Like I said, I don't know if it's any good, but it might be worth a try.
I am currently working through the Little Schemer as well and use Emacs as my environment, along Quack, which adds additional support and utilities for scheme-mode within Emacs.
If you are planning on experimenting with other Lisps (e.g. Common Lisp), Emacs has excellent support for those dialects as well (Emacs itself can be customized with its own dialect of Lisp, appropriately named Emacs Lisp).
As far as Scheme implementations go, I am currently using Petit Chez Scheme, which is an interpreted, freely distributable version of Chez Scheme (which uses a compiler and costs money to obtain a license).