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package perfect-hash-generator

Perfect minimal hashing implementation in native Haskell A perfect hash function for a set S is a hash function that maps distinct elements in S to a set of integers, with no collisions. A minimal perfect hash function is a perfect hash function that maps n keys to n consecutive integers, e.g. the numbers from 0 to n-1. In contrast with the PerfectHash package, which is a binding to a C-based library, this package is a fully-native Haskell implementation. It is intended primarily for generating C code for embedded applications (compare to gperf). The output of this tool is a pair of arrays that can be included in generated C code for allocation-free hash tables. Though conceivably this data structure could be used directly in Haskell applications as a read-only hash table, it is not recommened, as lookups are about 10x slower than HashMap. This implementation was adapted from Steve Hanov's Blog.
Usage
The library is written generically to hash both strings and raw integers according to the FNV-1a algorithm. Integers are split by octets before hashing.
```
import Data.PerfectHash.Construction (createMinimalPerfectHash)
import qualified Data.Map as Map

tuples = [
(1000, 1)
, (5555, 2)
, (9876, 3)
]

lookup_table = createMinimalPerfectHash $ Map.fromList tuples
```
Generation of C code based on the arrays in lookup_table is left as an exercise to the reader. Algorithm documentation in the Data.PerfectHash.Hashing and Data.PerfectHash.Lookup modules will be helpful.
Demo
See the hash-perfectly-strings-demo and hash-perfectly-ints-demo, as well as the test suite, for working examples.
```
$ stack build
$ stack exec hash-perfectly-strings-demo
```
package persistent-discover

Persistent module discover utilities This package provides an executable for discovering Persistent model definition files, as well as a library function to glob all persistent model files. Please see the README on GitHub at https://github.com/parsonsmatt/persistent-discover#readme
package persistent-documentation

Documentation DSL for persistent entities A convenient DSL that allows you to attach documentation to persistent database entities
package persistent-mongoDB

Backend for the persistent library using mongoDB. MongoDB backend for the persistent library.
package persistent-mtl

Monad transformer for the persistent API A monad transformer and mtl-style type class for using the persistent API directly in your monad transformer stack.
package persistent-pagination

Efficient and correct pagination for persistent or esqueleto queries. Please see the README on GitHub at https://github.com/parsonsmatt/persistent-pagination#readme
package persistent-redis

Backend for persistent library using Redis. Based on the Redis package.
package persistent-typed-db

Type safe access to multiple database schemata. See README.md for more details, examples, and fun.
package pg-transact

A postgresql-simple transaction monad A postgresql-simple transaction monad
package pid1

Do signal handling and orphan reaping for Unix PID1 init processes Please see README.md or view Haddocks at https://www.stackage.org/package/pid1

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