https://github.com/pierric/tuple-ops

various operations on n-ary tuples via GHC.Generics
https://github.com/pierric/tuple-ops

Last synced: 16 days ago
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various operations on n-ary tuples via GHC.Generics

• Host: GitHub
• URL: https://github.com/pierric/tuple-ops
• Owner: pierric
• License: bsd-3-clause
• Created: 2018-01-16T11:46:13.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2020-08-15T19:02:58.000Z (over 4 years ago)
• Last Synced: 2024-04-23T07:18:43.451Z (9 months ago)
• Language: Haskell
• Size: 25.4 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# tuple-ops

operations on n-ary tuples by manipulating via GHC.Generics. Current only uncons is implemented.

## uncons

```

> uncons (1::Int)

(1,())

```

```

> uncons (1::Int,'a')

(1,'a')

```

```

> uncons (True,'a', "S")

(True,('a',"S"))

```

## design rational

uncons initially targets to work with C interfaces generated from C2HS. For example, the following definition  

```

{#fun MXSymbolInferShape as mxSymbolInferShapeImpl

    { id `SymbolHandle'

    , id `MXUInt'

    , withStringArray* `[String]'

    , withIntegralArray* `[Int]'

    , withIntegralArray* `[Int]'

    , alloca- `MXUInt' peek*

    , alloca- `Ptr MXUInt' peek*

    , alloca- `Ptr (Ptr MXUInt)' peek*

    , alloca- `MXUInt' peek*

    , alloca- `Ptr MXUInt' peek*

    , alloca- `Ptr (Ptr MXUInt)' peek*

    , alloca- `MXUInt' peek*

    , alloca- `Ptr MXUInt' peek*

    , alloca- `Ptr (Ptr MXUInt)' peek*

    , alloca- `Int' peekIntegral*

    } -> `Int' #}

```

generates a function that returns `(Int, MXUInt, Ptr MXUInt, Ptr (Ptr MXUInt), MXUInt, Ptr MXUInt, Ptr (Ptr MXUInt), 

MXUInt, Ptr MXUInt, Ptr (Ptr MXUInt), Int)`, in which the first element is return code. By `uncons` it, we can extract the

return code, throwing an exception when an error is indicated, and return the rest part as result.

`uncons` also fits  a function returning a return-code only. In this case, `()` is the result after extraction.

## limits

only tuple of size up to 16 is supported.