heinrichapfelmus / vault Goto Github PK

A typed, persistent store for values of arbitrary types

License: BSD 3-Clause "New" or "Revised" License

Haskell 43.54% C 56.46%

haskell immutable-datastructures type-safety

vault's Introduction

Vault is a tiny library that provides a single data structure called vault.

A vault is a type-safe, persistent storage for values of arbitrary types. Like IORef, I want to be able to store values of any type in it, but unlike IORef, I want the storage space to behave like a persistent, first-class data structure, as appropriate for a purely functional language.

It is analogous to a bank vault, where you can access different bank boxes with different keys; hence the name.

In other words, a vault is an abstract data type with the following basic signature

data Key a
data Vault

newKey :: IO (Key a)
empty  :: Vault
lookup :: Key a -> Vault -> Maybe a
insert :: Key a -> a -> Vault -> Vault
delete :: Key a -> Vault -> Vault

A few common functions for finite maps, like adjust and union, are provided as well.

This library was created thanks to the feedback on my blog post Vault - a persistent store for values of arbitrary types.

Installation

The whole thing is available on hackage, so you just have to type

cabal update
cabal install vault

Feedback

Use the issue tracker or send an email to the maintainer.

vault's People

Contributors

Stargazers

Watchers

Forkers

ehird ozelis clockfort changaco snoyberg tarrasch luite silky guibou mdeltax thielema mrkkrp christopherdavenport templatek felixonmars steell awjchen sysfce2 andreasabel tchoutri

vault's Issues

Allow GHC 8.0

GHC 8.0 ships with base-4.9, which is disallowed by vault. A new release which can be used with GHC would be useful, and would allow me to test my downstream projects with GHC 8.0.

Variant that uses no GHC-specific extensions / functions

In an effort to make the reactive-banana library compile on UHC, I would like to include a variant of the vault package that doesn't use any GHC-specific functions. Of course, the best way to do this is to use the CPP preprocessor.

The only trouble is probably the ST monad which UHC likely doesn't have. However, I think that ST can be implemented in terms of unsafePerformIO, so it's easy to add it to the UHC libraries.

Is vault thread-safe?

I don't see this addressed anywhere in the docs, and I assume that it isn't thread-safe, but I just wanted to check.

Unclear dependency (instance Hashable Unique) makes reactive-banana build fail

I am unsure whether this is about reactive-banana or about vault. The issue originates here but shows in the other package.

Today, I manually installed packages into a fresh ghc-7.6.3 build to ultimately get a working reactive-banana package. The compiler is a custom version but corresponds to ghc-7.6.3 in functionality by default.

The manual installation was done using the following commands while standing in each package directory:
myGHC Setup.hs
./Setup configure --with-ghc=myGHC --global
./Setup build
./Setup register --inplace

Dependencies shown on hackage suggested the following installation order:
vault - text - hashable - unordered-containers - reactive-banana
This is wrong, as I found out later. The build of reactive-banana fails with error No instance for (Hashable Unique).
The vault cabal file specifies an additional vault dependency on hashable controlled by flag UseGHC (default true); if the flag is set, the instance will be declared. Rebuilding vault after the installation of hashable fixed the error, the build of reactive-banana went through.

So, where does a fix belong?
A fix inside reactive-banana would probably test the Hashable instance, but would not help users identify the issue. Better would be to make sure vault does not build with GHC when the flag was not unset explicitly. Ultimately, this might be a cabal issue? (too eagerly trying to install packages with flags that later create incompatibilities).

/ Jost

release a new version on hackage (or make a hackage revision) to support hashable-1.3.0.0

There is a new major release of hashable. As far as I can see, bumping the upper bound is enough to support it.

Interestingly, this is actually causing problems at the moment (cabal-install is having a hard time finding installation plans, e.g. lambdabot/lambdabot#183).

Travis integration is broken

For example, in #30, there is no indication whether the Travis build succeeded or not.

I have already experienced this in several other repos, and it has already caused me quite a bit of pain.

@HeinrichApfelmus, since you're the admin of this repo, I think only you can fix this. Could you try following the instructions that I posted in quchen/prettyprinter#172 (comment)?

Support GHC-9.6

Revision 2 of version 0.3.1.5 on Hackage disallows base-4.18, which is the version of base shipped in GHC 9.6.1. It would be nice if this version was supported.

Export either Vault.Lazy or Vault.Strict as Vault, again

In vault-0.2 we had the module Data.Vault which was split into Data.Vault.Lazy and Data.Vault.Strict in vault-0.3. Can I have back a Data.Vault that re-exports either Data.Vault.Lazy and Data.Vault.Strict? This would be analogous to Data.Map that re-exports Data.Map.Lazy. It would both show the programmer the prefered Vault variant and allows him to support both vault-0.2 and vault-0.3 by importing Data.Vault.
However in order to allow simple version ranges like vault >=0.2 && <0.4 it would be necessary to deprecate vault-0.3 at Hackage.

Control.Monad.ST.Unsafe not found

Trying to build version 0.2.0.3 on Windows

Invalid link in haddock on hackage

Not sure if it is a problem of vault and not of hackage itself - on page http://hackage.haskell.org/package/vault-0.3.0.2/docs/Data-Unique-Really.html link for Data.Unique contains local URI with file:// scheme

code duplication

The code of this package is very redundant, I suggest using CPP to refactor it, like this: Changaco/vault@master...factorize

Vault fails to install with Cabal 1.18.0.1

(It looks like it is a missing file in the vault package, "IO.hs")

cabal install vault
Resolving dependencies...
Configuring vault-0.3.0.1...
Building vault-0.3.0.1...
Preprocessing library vault-0.3.0.1...

src/Data/Vault/Lazy.hs:6:0:
fatal error: IO.hs: No such file or directory
compilation terminated.
Failed to install vault-0.3.0.1
cabal: Error: some packages failed to install:
vault-0.3.0.1 failed during the building phase. The exception was:
ExitFailure 1

GHC 9.10 compat

The package v0.3.1.5 excludes base-4.20, which is the version that ghc9.10 uses according to release notes

GHC 9.8 compat

This seems to work, so a revision could be sufficient:

 % cabal get vault
Unpacking to vault-0.3.1.5/
 % cd vault-0.3.1.5 
 % cabal repl --allow-newer=vault:base