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JordanMartinezJordanMartinez
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Fix type inference by exposing classless API (#53)
* Drop unused import * Fix type inference via classless API
1 parent 4ec460a commit f481921

5 files changed

Lines changed: 281 additions & 51 deletions

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‎CHANGELOG.md‎

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@@ -5,6 +5,43 @@ Notable changes to this project are documented in this file. The format is based
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## [Unreleased]
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Breaking changes:
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- Expose Buffer API using typeclass-less API witout removing typeclass API (#53 by @JordanMartinez)
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Previously, compiler would fail to infer the type of `Buffer.create 1` as `Effect Buffer`
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because the Buffer API was exposed only via the multiparameter typeclass `MonadBuffer`.
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Due to the functional dependency between the two parameters, the monadic type cannot be inferred
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until the buffer type is known (either `Buffer` or `STBuffer`).:
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```purs
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import Node.Buffer as Buffer
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-- Example 1
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main :: Effect Unit
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main = do
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x <- Buffer.create 1 -- compiler: is this `Int -> Effect Buffer` or `Int -> ST h (STBuffer h)?
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pure unit
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```
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The workaround was to add a type annotation, indicating the `x` is a `Buffer`:
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```purs
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import Node.Buffer as Buffer
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-- Example 2
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main :: Effect Unit
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main = do
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x :: Buffer <- Buffer.create 1 -- compiler: Oh! It's `Int -> Effect Buffer`
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pure unit
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```
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This change does not break anyone's code if one was using a `create` (or another such typeclass member)
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to get `Int -> Effect Buffer`. Rather, such users can now drop the `:: Buffer` annotation
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(i.e. Example 1 above now compiles).
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If one was using `create` to get `forall m buf. MonadBuffer buf m => Int -> m buf`,
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then one will need to update their imports:
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```diff
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-import Node.Buffer (class MonadBuffer)
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+import Node.Buffer.Class (class MonadBuffer)
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```
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New features:
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‎src/Node/Buffer.purs‎

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@@ -2,39 +2,136 @@
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module Node.Buffer
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( Buffer
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, module TypesExports
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, module Class
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, create
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, freeze
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, unsafeFreeze
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, thaw
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, unsafeThaw
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, fromArray
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, fromString
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, fromArrayBuffer
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, toArrayBuffer
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, read
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, readString
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, toString
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, write
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, writeString
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, toArray
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, getAtOffset
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, setAtOffset
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, slice
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, size
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, concat
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, concat'
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, copy
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, fill
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) where
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import Prelude
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import Data.ArrayBuffer.Types (ArrayBuffer)
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import Data.Maybe (Maybe)
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import Effect (Effect)
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import Node.Buffer.Class (class MutableBuffer)
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import Node.Buffer.Class (class MutableBuffer, concat, concat', copy, create, fill, freeze, fromArray, fromArrayBuffer, fromString, getAtOffset, read, readString, setAtOffset, size, slice, thaw, toArray, toArrayBuffer, toString, unsafeFreeze, unsafeThaw, write, writeString) as Class
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import Node.Buffer.Immutable (ImmutableBuffer)
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import Node.Buffer.Internal as Internal
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import Node.Buffer.Types (BufferValueType(..), Octet, Offset) as TypesExports
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import Node.Buffer.Types (BufferValueType)
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import Node.Encoding (Encoding)
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-- | A reference to a mutable buffer for use with `Effect`
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foreign import data Buffer :: Type
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instance mutableBufferEffect :: MutableBuffer Buffer Effect where
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create = Internal.create
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freeze = Internal.copyAll
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unsafeFreeze = Internal.unsafeFreeze
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thaw = Internal.copyAll
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unsafeThaw = Internal.unsafeThaw
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fromArray = Internal.fromArray
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fromString = Internal.fromString
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fromArrayBuffer = Internal.fromArrayBuffer
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toArrayBuffer = Internal.toArrayBuffer
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read = Internal.read
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readString = Internal.readString
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toString = Internal.toString
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write = Internal.write
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writeString = Internal.writeString
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toArray = Internal.toArray
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getAtOffset = Internal.getAtOffset
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setAtOffset = Internal.setAtOffset
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slice = Internal.slice
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size = Internal.size
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concat = Internal.concat
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concat' = Internal.concat'
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copy = Internal.copy
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fill = Internal.fill
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create = create
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freeze = freeze
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unsafeFreeze = unsafeFreeze
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thaw = thaw
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unsafeThaw = unsafeThaw
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fromArray = fromArray
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fromString = fromString
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fromArrayBuffer = fromArrayBuffer
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toArrayBuffer = toArrayBuffer
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read = read
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readString = readString
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toString = toString
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write = write
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writeString = writeString
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toArray = toArray
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getAtOffset = getAtOffset
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setAtOffset = setAtOffset
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slice = slice
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size = size
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concat = concat
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concat' = concat'
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copy = copy
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fill = fill
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create :: Int -> Effect Buffer
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create = Internal.create
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freeze :: Buffer -> Effect ImmutableBuffer
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freeze = Internal.copyAll
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unsafeFreeze :: Buffer -> Effect ImmutableBuffer
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unsafeFreeze = Internal.unsafeFreeze
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thaw :: ImmutableBuffer -> Effect Buffer
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thaw = Internal.copyAll
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unsafeThaw :: ImmutableBuffer -> Effect Buffer
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unsafeThaw = Internal.unsafeThaw
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fromArray :: Array Int -> Effect Buffer
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fromArray = Internal.fromArray
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fromString :: String -> Encoding -> Effect Buffer
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fromString = Internal.fromString
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fromArrayBuffer :: ArrayBuffer -> Effect Buffer
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fromArrayBuffer = Internal.fromArrayBuffer
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toArrayBuffer :: Buffer -> Effect ArrayBuffer
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toArrayBuffer = Internal.toArrayBuffer
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read :: BufferValueType -> Int -> Buffer -> Effect Number
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read = Internal.read
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readString :: Encoding -> Int -> Int -> Buffer -> Effect String
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readString = Internal.readString
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toString :: Encoding -> Buffer -> Effect String
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toString = Internal.toString
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write :: BufferValueType -> Number -> Int -> Buffer -> Effect Unit
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write = Internal.write
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writeString :: Encoding -> Int -> Int -> String -> Buffer -> Effect Int
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writeString = Internal.writeString
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toArray :: Buffer -> Effect (Array Int)
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toArray = Internal.toArray
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getAtOffset :: Int -> Buffer -> Effect (Maybe Int)
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getAtOffset = Internal.getAtOffset
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setAtOffset :: Int -> Int -> Buffer -> Effect Unit
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setAtOffset = Internal.setAtOffset
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slice :: Int -> Int -> Buffer -> Buffer
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slice = Internal.slice
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size :: Buffer -> Effect Int
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size = Internal.size
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concat :: Array Buffer -> Effect Buffer
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concat = Internal.concat
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concat' :: Array Buffer -> Int -> Effect Buffer
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concat' = Internal.concat'
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copy :: Int -> Int -> Buffer -> Int -> Buffer -> Effect Int
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copy = Internal.copy
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fill :: Int -> Int -> Int -> Buffer -> Effect Unit
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fill = Internal.fill

‎src/Node/Buffer/ST.purs‎

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@@ -1,15 +1,42 @@
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module Node.Buffer.ST
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( STBuffer
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, run
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, create
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, freeze
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, unsafeFreeze
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, thaw
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, unsafeThaw
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, fromArray
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, fromString
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, fromArrayBuffer
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, toArrayBuffer
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, read
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, readString
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, toString
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, write
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, writeString
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, toArray
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, getAtOffset
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, setAtOffset
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, slice
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, size
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, concat
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, concat'
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, copy
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, fill
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) where
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import Prelude
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import Control.Monad.ST (ST, Region)
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import Control.Monad.ST as ST
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import Node.Buffer.Class (class MutableBuffer, unsafeFreeze)
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import Data.ArrayBuffer.Types (ArrayBuffer)
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import Data.Maybe (Maybe)
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import Node.Buffer (BufferValueType)
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import Node.Buffer.Class (class MutableBuffer)
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import Node.Buffer.Immutable (ImmutableBuffer)
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import Node.Buffer.Internal as Internal
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import Node.Encoding (Encoding)
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-- | A reference to a mutable buffer for use with `ST`
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-- |
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run st = ST.run (st >>= unsafeFreeze)
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instance mutableBufferST :: MutableBuffer (STBuffer h) (ST h) where
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create = Internal.create
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freeze = Internal.copyAll
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unsafeFreeze = Internal.unsafeFreeze
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thaw = Internal.copyAll
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unsafeThaw = Internal.unsafeThaw
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fromArray = Internal.fromArray
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fromString = Internal.fromString
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fromArrayBuffer = Internal.fromArrayBuffer
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toArrayBuffer = Internal.toArrayBuffer
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read = Internal.read
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readString = Internal.readString
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toString = Internal.toString
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write = Internal.write
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writeString = Internal.writeString
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toArray = Internal.toArray
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getAtOffset = Internal.getAtOffset
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setAtOffset = Internal.setAtOffset
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slice = Internal.slice
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size = Internal.size
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concat = Internal.concat
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concat' = Internal.concat'
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copy = Internal.copy
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fill = Internal.fill
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create = create
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freeze = freeze
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unsafeFreeze = unsafeFreeze
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thaw = thaw
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unsafeThaw = unsafeThaw
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fromArray = fromArray
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fromString = fromString
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fromArrayBuffer = fromArrayBuffer
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toArrayBuffer = toArrayBuffer
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read = read
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readString = readString
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toString = toString
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write = write
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writeString = writeString
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toArray = toArray
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getAtOffset = getAtOffset
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setAtOffset = setAtOffset
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slice = slice
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size = size
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concat = concat
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concat' = concat'
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copy = copy
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fill = fill
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create :: forall h. Int -> ST h (STBuffer h)
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create = Internal.create
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freeze :: forall h. STBuffer h -> ST h ImmutableBuffer
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freeze = Internal.copyAll
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unsafeFreeze :: forall h. STBuffer h -> ST h ImmutableBuffer
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unsafeFreeze = Internal.unsafeFreeze
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thaw :: forall h. ImmutableBuffer -> ST h (STBuffer h)
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thaw = Internal.copyAll
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unsafeThaw :: forall h. ImmutableBuffer -> ST h (STBuffer h)
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unsafeThaw = Internal.unsafeThaw
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fromArray :: forall h. Array Int -> ST h (STBuffer h)
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fromArray = Internal.fromArray
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fromString :: forall h. String -> Encoding -> ST h (STBuffer h)
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fromString = Internal.fromString
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fromArrayBuffer :: forall h. ArrayBuffer -> ST h (STBuffer h)
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fromArrayBuffer = Internal.fromArrayBuffer
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toArrayBuffer :: forall h. STBuffer h -> ST h ArrayBuffer
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toArrayBuffer = Internal.toArrayBuffer
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read :: forall h. BufferValueType -> Int -> STBuffer h -> ST h Number
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read = Internal.read
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readString :: forall h. Encoding -> Int -> Int -> STBuffer h -> ST h String
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readString = Internal.readString
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toString :: forall h. Encoding -> STBuffer h -> ST h String
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toString = Internal.toString
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write :: forall h. BufferValueType -> Number -> Int -> STBuffer h -> ST h Unit
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write = Internal.write
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writeString :: forall h. Encoding -> Int -> Int -> String -> STBuffer h -> ST h Int
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writeString = Internal.writeString
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toArray :: forall h. STBuffer h -> ST h (Array Int)
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toArray = Internal.toArray
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getAtOffset :: forall h. Int -> STBuffer h -> ST h (Maybe Int)
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getAtOffset = Internal.getAtOffset
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setAtOffset :: forall h. Int -> Int -> STBuffer h -> ST h Unit
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setAtOffset = Internal.setAtOffset
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slice :: forall h. Int -> Int -> STBuffer h -> STBuffer h
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slice = Internal.slice
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size :: forall h. STBuffer h -> ST h Int
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size = Internal.size
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concat :: forall h. Array (STBuffer h) -> ST h (STBuffer h)
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concat = Internal.concat
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concat' :: forall h. Array (STBuffer h) -> Int -> ST h (STBuffer h)
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concat' = Internal.concat'
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copy :: forall h. Int -> Int -> STBuffer h -> Int -> STBuffer h -> ST h Int
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copy = Internal.copy
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fill :: forall h. Int -> Int -> Int -> STBuffer h -> ST h Unit
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fill = Internal.fill

‎test/Test/Node/Buffer/Class.purs‎

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Original file line numberDiff line numberDiff line change
@@ -7,7 +7,8 @@ import Data.Maybe (Maybe(..))
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import Data.Traversable (traverse)
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import Effect (Effect)
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import Effect.Console (log)
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import Node.Buffer (class MutableBuffer, BufferValueType(..), concat', copy, create, fill, freeze, fromArray, fromArrayBuffer, fromString, getAtOffset, read, readString, setAtOffset, slice, thaw, toArray, toArrayBuffer, toString, write)
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import Node.Buffer.Class (class MutableBuffer, concat', copy, create, fill, freeze, fromArray, fromArrayBuffer, fromString, getAtOffset, read, readString, setAtOffset, slice, thaw, toArray, toArrayBuffer, toString, write)
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import Node.Buffer (BufferValueType(..))
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import Node.Buffer.Immutable as Immutable
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import Node.Encoding (Encoding(..))
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import Test.Assert (assertEqual)

‎test/Test/Node/Buffer/ST.purs‎

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@@ -2,7 +2,6 @@ module Test.Node.Buffer.ST (test) where
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import Prelude
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5-
import Control.Monad.ST (run) as ST
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import Effect (Effect)
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import Effect.Console (log)
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import Node.Buffer.Class (create)

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