Unanswered Questions

27
votes
0answers
2k views

Why (or why not) are existential types considered bad practice in functional programming?

What are some techniques I might use to consistently refactor code removing the reliance on existential types? Typically these are used to disqualify undesired constructions of your type as well as to ...
10
votes
2answers
495 views

In-memory datastore in Haskell

I want to implement an in-memory datastore for a web service in Haskell. I want to run transactions in the STM monad. When I google hash table steam Haskell I only get this: Data. BTree. HashTable. ...
9
votes
0answers
284 views

How to implement a branch-and-bound in a functional programming language?

I am trying to write a branch and bound search on the set of all functions f: D -> R, where the domain size is small (|D| ~ 20) and the range is much bigger (|R| ~ 2^20). Initially, I came up with the ...
8
votes
1answer
791 views

Useful design patterns for working with FragmentManager on Android

When working with fragments, I have been using a class composed of static methods that define actions on fragments. For any given project, I might have a class called FragmentActions, which contains ...
6
votes
1answer
110 views

Are “skip deltas” unique to svn?

The good folks who created the SVN version control system use a structure they refer to as "skip deltas" to store the revision history of files internally. A revision is stored as a delta against an ...
6
votes
0answers
139 views

Using uniqueness types to implement safe parallelism

I've been interested in uniqueness types as an alternative to monads in pure functional languages for some time; unfortunately, this is kind of an esoteric area of CS research and online resources ...
6
votes
1answer
153 views

Heuristic Approach for Flexible DIFF Implementation

I have created a DIFF implementation to compare document revisions at work. It is based on An O(ND) Difference Algorithm and Its Variations. One thing that has become important is to take the list ...
5
votes
1answer
635 views

Attachment handling for web application with Jackrabbit

I need to manage attachments on my Spring web application and I thought to use an open source repository. My app it's a job approval system using J2EE / SPRING 3 Framework and Postgress DB to allow ...
5
votes
4answers
371 views

Adding field to the class at runtime - design pattern

Imagine your customer want's to have a possibility to add new property (e.g. color) to product in their eshop in their CMS. Instead of having properties as fields: class Car extends Product { ...
4
votes
0answers
88 views

How to represent hard-to-calculate “properties” of “objects” in functional code?

I have a polyline "class" in my Clojure program, which is represented by a vector of points. (It's not really a class or anything.) The polyline's length (in the geometric sense) is something that is ...
4
votes
3answers
124 views

Using mocks to set up object even if you will not be mocking any behavior or verifying any interaction with it?

When building a unit test, is it appropriate to use a mocking tool to assist you in setting up an object even if you will not be mocking any behavior or verifying any interaction with that object? ...
4
votes
1answer
231 views

What are the benefits of Android way of “saving memory” - explicitly passing Context objects everywhere?

Turned out, this question is not easy to formulate for me, but let's try. In Android, pretty much any UI object depends on a Context, and has defined lifetime. Android can also destroy and recreate UI ...
4
votes
1answer
875 views

Help with complex MVVM (multiple views)

I need help creating view models for the following scenario: Deep, hierarchical data Multiple views for the same set of data Each view is a single, dynamically-changing view, based on the active ...
4
votes
0answers
3k views

using dbus on Android

I would like to know if it is possible to use DBUS on Android using Java. From what I have been searching till now it appears like there is no DBUS programming support on Android. But then bluetooth ...
4
votes
1answer
283 views

Loose Coupling Presenter to View in MVP

We work in a Java shop here and our web application uses an implementation of the MVP architectural pattern. Our manager comes from a .NET world, where he has been exposed to the MVVM design pattern. ...

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