purescript-bytestrings

An immutable byte string type, with mutable ST buffers and String codecs.

Installation

spago install bytestrings

Scope

Data.ByteString — the immutable ByteString type and its pure operations
Data.ByteString.ST — mutable STByteString h buffers
Data.ByteString.Encoding — String conversions: UTF8, UTF16LE, Latin1, Hex, Base64

Example

import Data.ByteString (bytes, take)
import Data.ByteString.Encoding (Encoding(..), fromString, fromStringLossy, toString, toStringLossy)

main = do
  -- encode a string to bytes: `fromString` returns `Nothing` if it can't convert
  assertEqual { actual: fromString UTF8 "hi!", expected: Just (bytes [ 0x68, 0x69, 0x21 ]) }

  -- `fromStringLossy` is the total variant, doesn't return a `Maybe` and substitutes things it can't represent
  let bs = fromStringLossy UTF8 "hi!"

  -- render the bytes as hex
  assertEqual { actual: toString Hex bs, expected: Just "686921" }

  -- slice, then decode back to a string
  assertEqual { actual: toString UTF8 (take 2 bs), expected: Just "hi" }

  -- strict decoding is `Nothing` on invalid input; the `Lossy` variants are
  -- total and substitute instead
  assertEqual { actual: toString UTF8 (bytes [ 0x80 ]), expected: Nothing }
  assertEqual { actual: toStringLossy UTF8 (bytes [ 0x80 ]), expected: "\xFFFD" }

See the tests to see usages.

Development

Sources are formatted with purs-tidy:

purs-tidy format-in-place src test

Documentation

Module documentation is published on Pursuit.