lenses | small functional lens library for TypeScript with the goal | Serialization library

 by   atomicobject TypeScript Version: Current License: MIT

kandi X-RAY | lenses Summary

kandi X-RAY | lenses Summary

lenses is a TypeScript library typically used in Utilities, Serialization applications. lenses has no bugs, it has no vulnerabilities, it has a Permissive License and it has low support. You can download it from GitHub.

@atomic-object/lenses is a small functional lens library for TypeScript with the goal of being small, with zero dependencies, and strong, precise types. It is inspired by Aether, for F#. Lenses are getter/setter pairs that let you represent a location within some data structure for both reading and updating that location. "Update" in this case is in the functional sense – not by mutation, but by creating a new data structure with a new value in the location of interest. A little like a pointer offset in C, but memory-, type-, and mutation-safe.
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            kandi-support Support

              lenses has a low active ecosystem.
              It has 55 star(s) with 6 fork(s). There are 13 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              There are 2 open issues and 1 have been closed. There are 4 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of lenses is current.

            kandi-Quality Quality

              lenses has 0 bugs and 0 code smells.

            kandi-Security Security

              lenses has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              lenses code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              lenses is licensed under the MIT License. This license is Permissive.
              Permissive licenses have the least restrictions, and you can use them in most projects.

            kandi-Reuse Reuse

              lenses 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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            lenses Key Features

            No Key Features are available at this moment for lenses.

            lenses Examples and Code Snippets

            No Code Snippets are available at this moment for lenses.

            Community Discussions

            QUESTION

            Simplification of way too long Haskell function
            Asked 2022-Apr-11 at 17:29

            I wrote a function to query currency exchanges rate from an API. It works fine, but the code is way too long and unreadable. I thought someone would be able to help me simplify this, especially because there are many repeated patterns and operators like the repeated use of

            EDIT: I didn't realize that binding anything to pure is absolutely useless!

            ...

            ANSWER

            Answered 2022-Apr-10 at 18:00

            Wow, that is too long. Let's take it step by step; by the end, we will arrive at the following code snippet which I find much more natural to read but which performs exactly the same computation:

            Source https://stackoverflow.com/questions/71817452

            QUESTION

            android camera 2 must use only camera devices supporting backward compatibility
            Asked 2022-Mar-30 at 00:06

            I am building an android application that lists down all camera devices, I want to list down all the camera devices and allow the user to use them all and not only that, I want also to allow the user to change the play with the resolution as they want, so I follow this link: https://developer.android.com/training/camera2/camera-enumeration

            It recommends only using the camera devices with the flag:

            ...

            ANSWER

            Answered 2022-Mar-30 at 00:06

            BACKWARD_COMPATIBLE devices are ones that support YUV and JPEG output and a bunch of basic camera behavior.

            In general, only very few camera types won't list BACKWARD_COMPATIBLE; one such example is a pure depth camera, which won't produce JPEGs. For such devices, you have to manually check what output formats are actually supported via 'getOutputFormats', since it's likely something like JPEG won't be listed, or it may only support monochrome output and not color, which may make it impossible to use it with a video recorder.

            If you're seeing a lot of devices get filtered out by excluding BACKWARD_COMPATIBLE, it'd be interesting to know, since in my experience they're very rare.

            Source https://stackoverflow.com/questions/71654282

            QUESTION

            Do you compute the fundamental matrix every iteration? (Stereo Vision)
            Asked 2022-Mar-14 at 23:41

            I am filling a form about joining a student team. There are some questions about computer vision. I had a little experience before hand, and i spent two days already researching the basics about depth estimation. I have the following question about the implementation of depth estimation.

            Lets say i have a moving vehicle, and i am using cameras to estimate depth of various objects. Knowing the fundamental matrix, depth estimation boils down to solving a 3x3 linear system for each point in space. (Assuming there are no uncertainties with the pixel coordinates, or distortion from lenses).

            The fundamental matrix itself is calculated using corresponding points from the 2 images. The question is, do i have to calculate the fundamental matrix at every moment (every iteration)? Do i calibrate the cameras at the initial setup and after that, the fundamental matrix is considered known?

            ...

            ANSWER

            Answered 2022-Mar-14 at 23:41

            Once you calibrate your system, if extrinsic (relative position) and intrinsic (camera lenses, focal length, image resolution) parameters remain the same, then you don't need to recalculate the fundamental matrix F. You do it only once, and may store it for future use.

            This is exactly what I do in my library, where you can find also an example where the fundamental matrix is calculated and used to draw epipolar lines.

            I hope this answers your question.

            Cheers

            Source https://stackoverflow.com/questions/71456513

            QUESTION

            How to convert this UIGraphics image operation to Core Image?
            Asked 2022-Mar-02 at 10:05

            I write SplitMirror filter like in Apple Motion app or Snapchat lenses by using UIGraphics to use it with real time camera feed or video processing, with single image request it works well like in attached image in the question but for multiple filtering request not. I think it's code must be changed from UIGraphics to Core Image & CIContext for better performance and less memory usage like CIFilters and actually I don't know how to do it. I tried several ways to convert it but I stuck on merging left and right, this can be done with `CICategoryCompositeOperations filters but which one is fit this case I o have idea, so need some help with this issue.

            Filter code using UIGraphics:

            ...

            ANSWER

            Answered 2022-Mar-02 at 08:02

            I think you are on the right track.

            You can create the left half from the right half by applying transformations to it using let leftHalf = rightHalf.transformed(by: transformation). The transformation should mirror it and translate it to the correct position, i.e., next to the right half.

            You can them combine the two into one image using let result = leftHalf.composited(over: rightHalf) and render that result using a CIContext.

            Source https://stackoverflow.com/questions/71307022

            QUESTION

            How to use lens to access a record field behind a sum type
            Asked 2022-Mar-01 at 21:47

            I am trying to access a nested record using lenses and prisms in Haskell:

            ...

            ANSWER

            Answered 2022-Mar-01 at 21:09

            Updated: As per comments, I've fixed some errors and added a few asides in [[double square brackets]].

            Here's how/why your first mMistake works...

            A prism is an optic that focus on a "part" that may or may not be present in the "whole". [[Technically, it focuses on the sort of part that can be used to reconstruct an entire whole, so it really pertains to a whole that can come in several alternative forms (as in the case of a sum type), with the "part" being one of those alternative forms. However, if you're only using a prism for viewing and not setting, this added functionality isn't too important.]]

            In your example, both _StateRun and _Just are prisms. The _Just prism focuses on the a part of a Maybe a whole. Such an a may or may not be present. If the Maybe a value is Just x for some x :: a, the part a is present and has value x, and that's what _Just focuses on. If the Maybe a value is Nothing, then the part a is not present, and _Just doesn't focus on anything.

            It's somewhat similar for your prism _StateRun. If the whole StateStep is a StateRun x y value, then _StateRun focuses on that "part", represented as a tuple of the fields of the StateRun constructor, namely (x, y) :: (Int, Maybe Text). On the other hand, if the whole StateStep is a StatePause, that part isn't present, and the prism doesn't focus on anything.

            When you compose prisms, like _StateRun and _Just, and lenses, like stStep and _2, you create a new optic that combines the composed series of focusing operations.

            [[As was pointed out in the comments, this new optic isn't a prism; it's "only" traversal. In fact, it's a specific kind of traversal, called an "affine traversal". A run-of-the-mill traversal can focus on zero or more parts, while an affine traversal focuses on exactly zero (part not present) or one (unique part present). The lens library doesn't make the distinction between affine traversals and other sorts of traversals, though. The reason the new optic is "only" an affine traversal instead of a prism relates to that earlier technical point. Once you add lenses, you remove your ability to reconstruct the entire "whole" from a single "part". Again, if you're only using the optics for viewing, not setting, it won't really matter.]]

            Anyway, consider the optic (affine traversal):

            Source https://stackoverflow.com/questions/71301462

            QUESTION

            Haskell lens : view doesn't reference like over and set?
            Asked 2022-Feb-20 at 23:35

            First time using lens. set and over went easy enough and I thought it would be simple with view: Use the same scheme to reference the inner part, but don't supply a new value or function. But Noooo. tst3 below gives the error below the code. Anyone know what's going on?

            ...

            ANSWER

            Answered 2022-Feb-20 at 23:35

            ix 0 doesn't produce a lens, but a traversal.1

            Informally, a lens is a "path" that will definitively reach a single value (if you follow it within a hypothetical larger value). A traversal is a path to zero or more values. You can set or view the single target of a lens. And you can set the zero or more targets of a traversal (this simply updates all of them that are present, which is a no-op if there are zero present). But viewing the targets of a traversal is less straightforward.

            If view simply took a traversal, and an outer structure, and gave you the target value, then it would have a problem. If there are multiple targets, how should it decide which to return? And if there are zero targets, it can't return anything; it would have to be partial. What it needs is a way of condensing zero-or-more values into a single value, so it can return that. And the Monoid class provides exactly the facilities to do that; mempty for if there aren't any targets at all, and <> to condense multiple values to a single one. So view with a traversal2 actually requires a Monoid constraint on the returned type, and that's why you're getting the complaint about No instance for (Monoid Int) arising from a use of `ix'.

            And in case it isn't clear, you can often compose (with .) different types of optics (the general term for "lens-ish things", including lenses, traversals, and several others). But the result has the capabilities of the least capable of the two inputs. So even though your inner and w are full lenses, composing them with a traversal produced by ix results in a traversal, not a lens.

            But in this case you know that you're using ix. The specific kind of traversals ix makes end up having zero or one target, rather than the zero or more targets that traversals have in general. So you could use preview instead of view; for a traversal it will produce a Maybe containing Just the first target of the traversal, or Nothing if there weren't any. A Maybe is exactly what the type system deems appropriate here, since ix can't guarantee there will be a target value, but there won't be more than one.

            In my experience, when I try to view something and get this Monoid instance error, it almost always means I have an optic that can't guarantee a result and I should actually be using preview to get a Maybe.

            Simple example:

            Source https://stackoverflow.com/questions/71199266

            QUESTION

            How do I limit users to just the DBSQL lens of Databricks? I don't want them to have access to SQL endpoints or DE & ML lenses
            Asked 2022-Feb-01 at 19:22

            Here are the current options. I want to give the BI team only access to the S: SQL

            ...

            ANSWER

            Answered 2022-Feb-01 at 19:22

            Completely removing the other options is currently not available. However, you can lock them as shown in the picture.

            1. Remove databricks-sql-access entitlement from default users group.
            2. Create a new group called 'sql-users-only' and give them only this entitlement. (so they won't see workspace and they can't spin up endpoints)

            Resources: Databricks provide a lot of control using ACLs. Access control overview You can restrict the dashboard viewing options as well. Dashboard permissions

            Source https://stackoverflow.com/questions/70946256

            QUESTION

            Typescript types of composition Ramda lens with React useState set function
            Asked 2021-Dec-12 at 10:45

            I am learning FP and I am trying to figure out how to handle events in react. For example, let's use following scenario:

            ...

            ANSWER

            Answered 2021-Dec-12 at 10:45

            Add the type Todo to the lensProp call. You can also move it out of the component, because you don't need to generate the function whenever the component re-renders:

            Source https://stackoverflow.com/questions/70319897

            QUESTION

            Query 1:many relation in Android Room
            Asked 2021-Dec-08 at 19:43

            I am using Room in my Android App (Java) and there I have two entities with a 1:many relation.

            Lens entity One lens can have multiple wears.

            ...

            ANSWER

            Answered 2021-Dec-08 at 19:43

            The parent column needs to be the column that forms the relationship between the two. That is it should be the fk_lensId column.

            So :-

            Source https://stackoverflow.com/questions/70279827

            QUESTION

            In C#.NET, how do I deserialize a JSON object that is not an array of objects, and has a unique name for every object?
            Asked 2021-Dec-07 at 13:03

            I have a JSON object that looks like this:

            ...

            ANSWER

            Answered 2021-Dec-07 at 12:57

            It seems like because the JSON object is not an array of objects, the deserializer cannot convert it to an IEnumerable

            Yes, it is not an array of objects, it is an object with others objects in it, I believe that using default serializers/deserializers you will not be able to work this JSON out.

            Unless you end up using dynamic objects (can be a JObject) and then cast it to another structure, the only way is to write a custom serializer for this specific case and build an workaround this JSON.

            You can try this:

            Source https://stackoverflow.com/questions/70260266

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

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            You can download it from GitHub.

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