lens-3.8.7.3: Lenses, Folds and Traversals

Portability | non-portable
Stability | experimental
Maintainer | Edward Kmett <ekmett@gmail.com>
Safe Haskell | None

Data.ByteString.Lens

Description

Synopsis

- class IsByteString t where
  - packedBytes :: Iso' [Word8] t
  - packedChars :: Iso' String t
  - bytes :: IndexedTraversal' Int t Word8
  - chars :: IndexedTraversal' Int t Char
- unpackedBytes :: IsByteString t => Iso' t [Word8]
- unpackedChars :: IsByteString t => Iso' t String

# Documentation

class IsByteString t where

Traversals for ByteStrings.

Methods

packedBytes :: Iso' [Word8] t

`pack` (or `unpack`) a list of bytes into a strict or lazy `ByteString`.

     pack x ≡ x ^. packedBytes
     unpack x ≡ x ^. from packedBytes
     packedBytes ≡ from unpackedBytes

packedChars :: Iso' String t

`pack` (or `unpack`) a list of characters into a strict or lazy `ByteString`.

When writing back to the `ByteString` it is assumed that every `Char` lies between `'\x00'` and `'\xff'`.

     pack x ≡ x ^. packedChars
     unpack x ≡ x ^. from packedChars
     packedChars ≡ from unpackedChars

bytes :: IndexedTraversal' Int t Word8

Traverse each `Word8` in a strict or lazy `ByteString`

This `Traversal` walks each strict `ByteString` chunk in a tree-like fashion enable zippers to seek to locations more quickly and accelerate many monoidal queries, but up to associativity (and constant factors) it is equivalent to the much slower:

     bytes ≡ unpackedBytes . traversed

     anyOf bytes (== 0x80) :: ByteString -> Bool

chars :: IndexedTraversal' Int t Char

Traverse the individual bytes in a strict or lazy `ByteString` as characters.

When writing back to the `ByteString` it is assumed that every `Char` lies between `'\x00'` and `'\xff'`.

This `Traversal` walks each strict `ByteString` chunk in a tree-like fashion enable zippers to seek to locations more quickly and accelerate many monoidal queries, but up to associativity (and constant factors) it is equivalent to the much slower:

     chars ≡ unpackedChars . traversed

     anyOf chars (== 'c') :: ByteString -> Bool

Instances

IsByteString ByteString |
IsByteString ByteString |

unpackedBytes :: IsByteString t => Iso' t [Word8]

`unpack` (or `pack`) a `ByteString` into a list of bytes

     unpackedBytes ≡ from packedBytes
     unpack x ≡ x ^. unpackedBytes
     pack x ≡  x ^. from unpackedBytes

     unpackedBytes :: Iso' ByteString [Word8]
     unpackedBytes :: Iso' ByteString [Word8]

unpackedChars :: IsByteString t => Iso' t String

`unpack` (or `pack`) a list of characters into a strict (or lazy) `ByteString`

When writing back to the `ByteString` it is assumed that every `Char` lies between `'\x00'` and `'\xff'`.

     unpackedChars ≡ from packedChars
     unpack x ≡ x ^. unpackedChars
     pack x ≡ x ^. from unpackedChars

     unpackedChars :: Iso' ByteString String
     unpackedChars :: Iso' ByteString String