forall | Expressive static types and invariant checks for JavaScript

by MaiaVictor JavaScript Version: Current License: MIT

X-Ray Key Features Code Snippets Community Discussions(10)Vulnerabilities Install Support

kandi X-RAY | forall Summary

forall is a JavaScript library. forall has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

Expressive static type and invariant checks for JavaScript. It is similar to TypeScript, but:. Yes, it can check claims such as "this function can't produce negative balances" at compile time. Sounds magical, but it is actually simple: the catch is that it isn't doing classical (logical) type-checking, but, instead, it "type-checks" by inspecting with random samples. It can, thus, be wrong sometimes. The hypothesis, though, is that, in practice, if your code is wrong, it will almost always spot it; and being wrong sometimes is compensated by catching a much larger class of bugs. In short, Forall.js attempts to give you some of the expressivity of Idris, with the ease-of-use of TypeScript, trading absolute for probabilistic correctness. You can see it as the fusion of a type system with automated tests.

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Support

forall has a low active ecosystem.

It has 229 star(s) with 4 fork(s). There are 7 watchers for this library.

It had no major release in the last 6 months.

There are 1 open issues and 0 have been closed. There are no pull requests.

It has a neutral sentiment in the developer community.

The latest version of forall is current.

Quality

forall has 0 bugs and 0 code smells.

Security

forall has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

forall code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

forall is licensed under the MIT License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

forall releases are not available. You will need to build from source code and install.

Installation instructions are not available. Examples and code snippets are available.

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forall Key Features

No Key Features are available at this moment for forall.

forall Examples and Code Snippets

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Community Discussions

Trending Discussions on forall

Homogenize a heterogenous list with a funtion that has a particular kind of context

Can a polymorphic constant be mapped over a list of *types*?

`forall {..}` in GHC 9

What is this GHC feature called? `forall` in type definitions

Instance inductivity as constraint

F# on Visual Studio 2022 very slow

How to map existentials with multiple constraints in Haskell?

Why `f x = x x` and `g x = x x x x x` have the same type

Why is my parallel code even slower than without parallelism?

Solving predicate calculus problems with Z3 SMT

QUESTION

Homogenize a heterogenous list with a funtion that has a particular kind of context

Asked 2022-Mar-28 at 12:28

I am fiddling with the basics of type-level programming in Haskell, and I was trying to write a function that "homogenizes" a heterogeneous list using a function with a context of kind (* -> *) -> Constraint (e.g., length or fmap (/= x)).

The heterogeneous list is defined as follows:

...

ANSWER

Answered 2022-Mar-11 at 22:45

Even though e.g. AllKind2 Foldable [] '[Int] does not match any equation for AllKind2, it is not understood to be an unsatisifiable constraint. (The general principle is undefined type family applications are just that: undefined, in the sense it could be something but you have no idea what it is.) That's why, even if you know AllKind2 c t (x : xs), you can not deduce x ~ t y for some y by saying "that's the only way to get a defined constraint from AllKind2." You need an equation for the general AllKind2 c t (x : xs) case that dispatches to a class that will contain the actual information.

Source https://stackoverflow.com/questions/71432206

QUESTION

Can a polymorphic constant be mapped over a list of *types*?

Asked 2022-Feb-09 at 00:00

Haskell hobbyist here - is it possible to map a polymorphic constant over a list of types in a generic way?

More precisely, consider this snippet:

...

ANSWER

Answered 2022-Feb-09 at 00:00

I wish someone can prove me wrong, but this is one of the few corner cases where we meet a limitation of current GHC and we can not get away from using Proxy, Tagged or similar "relics" of the past.

A minimal example

Let's consider a simpler example:

Source https://stackoverflow.com/questions/71040992

QUESTION

`forall {..}` in GHC 9

Asked 2022-Feb-04 at 00:08

This is valid syntax in GHC 9. What do the {..} mean (as distinct from (..) which GHC 8.10 requires here)?

...

ANSWER

Answered 2022-Feb-04 at 00:08

See 6.4.14.1. Inferred vs. specified type variables:

Since the 9.0.1 release, GHC permits labelling the user-written type or kind variables as inferred, in contrast to the default of specified. By writing the type variable binder in braces as {tyvar} or {tyvar :: kind}, the new variable will be classified as inferred, not specified.

.. is a specified type
{..} is an inferred type

forall a. and forall {a}. are invisible quantifiers that GHC will instantiate automatically by unification.

Source https://stackoverflow.com/questions/70978592

QUESTION

What is this GHC feature called? `forall` in type definitions

Asked 2022-Feb-01 at 19:28

I learned that you can redefine ContT from transformers such that the r type parameter is made implicit (and may be specified explicitly using TypeApplications), viz.:

...

ANSWER

Answered 2022-Feb-01 at 19:28

Nobody uses this (invisible dependent quantification) for this purpose (where the dependency is not used) but it is the same as giving a Type -> .. parameter, implicitly.

Source https://stackoverflow.com/questions/70946284

QUESTION

Instance inductivity as constraint

Asked 2022-Jan-25 at 19:53

I'm trying to express an idea that given

...

ANSWER

Answered 2022-Jan-25 at 19:53

You get the exact same error with the slightly simpler definition of Foo c m given here:

Source https://stackoverflow.com/questions/70853208

QUESTION

F# on Visual Studio 2022 very slow

Asked 2022-Jan-06 at 11:02

This only applies to Visual Studio 2022. I had uninstalled VS2019 and Preview where F# worked absolutely fine (F# 5.0). I am using VS2022 to use F# 6.0 and do not want to go back to F# 5.0.

The issue is specific to F#. I also use C# and I have no issues running the latest C# under VS2022.

There are near continual DevEnv processes running consuming anywhere from 1 to 4 of my CPU's 4 Hyperthreads. I have switched off all experimental options I can find in F# settings.

Sometimes there are 2 or more background processes running , sometimes paused and sometimes none - there appears to be no correlation between this and the background CPU consumption

Sometimes I have a pop up Dialog about waiting to complete an editor process or a compile process.

When devenev.exe is consuming CPU cycles under the properties I see there is always one clr.dllCoUnInitializeEE+0x6790 that is the culprit. I though this was meant to be a short-lived process? Sometimes there are two or three of these consuming most of a HyperThread (There are identical others but with very low or no CPU consumption). The stack on the guilty thread is as follows:

...

ANSWER

Answered 2021-Dec-17 at 08:49

Please report to Microsoft either using the people app in windows or the visual studio installer.

for now, there is only one option: use visual studio 2019. or try finding alternatives. there should be somewhere around the net

I suggest using Rider IDE instead(until the devs fix the bug):Download Rider IDE

I'm not really trying to advertise here, just suggesting an IDE Too compile and run you rprogram.

Source https://stackoverflow.com/questions/70262144

QUESTION

How to map existentials with multiple constraints in Haskell?

Asked 2021-Dec-17 at 01:49

I figured out how to process a list of heterogeneous types constrained by a single class:

...

ANSWER

Answered 2021-Dec-16 at 21:52

With enough language features, it's possible to make a constraint that combines constraints:

Source https://stackoverflow.com/questions/70385901

QUESTION

Why `f x = x x` and `g x = x x x x x` have the same type

Asked 2021-Dec-05 at 05:36

I'm playing with Rank-N-type and trying to type x x. But I find it counter intuitive that these two functions can be typed in the same way.

...

ANSWER

Answered 2021-Nov-08 at 16:22

The key is that x :: a -> b is a function that can provide a value of any type, no matter what argument is given. That means x can be applied to itself, and the result can be applied to x again, and so on and so on.

At least, that's what it promises the type checker it can do. The type checker isn't concerned about whether or not any such value exists, only that the types align. Neither f nor g can actually be called, because no such value of type a -> b exists (ignoring bottom and unsafeCoerce).

Source https://stackoverflow.com/questions/69884616

QUESTION

Why is my parallel code even slower than without parallelism?

Asked 2021-Nov-18 at 15:40

I followed Simon Marlow's book on parallel Haskell (Chapter 1) using rpar/rseq .

Below is the code (Solving the Squid Game bridge simulation):

...

ANSWER

Answered 2021-Oct-29 at 23:24

You aren't actually using any parallelism. You write

Source https://stackoverflow.com/questions/69774968

QUESTION

Solving predicate calculus problems with Z3 SMT

Asked 2021-Nov-04 at 13:24

I'd like to use Z3 to solve problems that are most naturally expressed in terms of atoms (symbols), sets, predicates, and first order logic. For example (in pseudocode):

...

ANSWER

Answered 2021-Oct-18 at 06:54

"Alloy seems designed more for interactive use to explore consistency of models, rather than to find specific solutions for problems."

IMHO, Alloy shines when it comes to validate your own way of thinking. You model something and through the visualization of several instances you can sometime come to realize that what you modeled is not exactly what you'd have hoped for. In that sense, I agree with you.

Yet, Alloy can also be used to find specific solutions to problems. You can overload a model with constraints so that only one instance can be found (i.e. your solution). It works also quite well when your domain space remains relatively small.

Here's your model translated in Alloy :

Source https://stackoverflow.com/questions/69607284

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Vulnerabilities

No vulnerabilities reported

Install forall

You can download it from GitHub.

Support

For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .

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