Explore using ST for effects (issue #24)

bower.json

@@ -15,11 +15,14 @@
   "dependencies": {
     "purescript-effect": "^2.0.0",
     "purescript-maybe": "^4.0.0",
-    "purescript-arraybuffer-types": "^2.0.0"
+    "purescript-arraybuffer-types": "^2.0.0",
+    "purescript-st": "^4.0.0",
+    "purescript-unsafe-coerce": "^4.0.0"
   },
   "devDependencies": {
     "purescript-assert": "^4.0.0",
     "purescript-console": "^4.1.0",
-    "purescript-foldable-traversable": "^4.0.0"
+    "purescript-foldable-traversable": "^4.0.0",
+    "purescript-proxy": "^3.0.0"
   }
 }

src/Node/Buffer.purs

@@ -1,164 +1,40 @@
+-- | Mutable buffers and associated operations.
 module Node.Buffer
-  ( Octet()
-  , Offset()
-  , Buffer()
-  , BufferValueType(..)
-  , create
-  , fromArray
-  , fromString
-  , fromArrayBuffer
-  , toArrayBuffer
-  , read
-  , readString
-  , toString
-  , write
-  , writeString
-  , toArray
-  , getAtOffset
-  , setAtOffset
-  , size
-  , concat
-  , concat'
-  , copy
-  , fill
+  ( Buffer
+  , module TypesExports
+  , module Class
   ) where
 
-import Prelude
-
 import Effect (Effect)
-import Data.ArrayBuffer.Types (ArrayBuffer)
-import Data.Maybe (Maybe(..))
-import Node.Encoding (Encoding, encodingToNode)
-
--- | Type synonym indicating the value should be an octet (0-255). If the value
--- | provided is outside this range it will be used as modulo 256.
-type Octet = Int
+import Node.Buffer.Class (class MutableBuffer)
+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
+import Node.Buffer.Internal as Internal
+import Node.Buffer.Types (BufferValueType(..), Octet, Offset) as TypesExports
 
--- | Type synonym indicating the value refers to an offset in a buffer.
-type Offset = Int
-
--- | An instance of Node's Buffer class.
+-- | A reference to a mutable buffer for use with `Effect`
 foreign import data Buffer :: Type
 
-instance showBuffer :: Show Buffer where
-  show = showImpl
-
-foreign import showImpl :: Buffer -> String
-
--- | Enumeration of the numeric types that can be written to a buffer.
-data BufferValueType
-  = UInt8
-  | UInt16LE
-  | UInt16BE
-  | UInt32LE
-  | UInt32BE
-  | Int8
-  | Int16LE
-  | Int16BE
-  | Int32LE
-  | Int32BE
-  | FloatLE
-  | FloatBE
-  | DoubleLE
-  | DoubleBE
-
-instance showBufferValueType :: Show BufferValueType where
-  show UInt8    = "UInt8"
-  show UInt16LE = "UInt16LE"
-  show UInt16BE = "UInt16BE"
-  show UInt32LE = "UInt32LE"
-  show UInt32BE = "UInt32BE"
-  show Int8     = "Int8"
-  show Int16LE  = "Int16LE"
-  show Int16BE  = "Int16BE"
-  show Int32LE  = "Int32LE"
-  show Int32BE  = "Int32BE"
-  show FloatLE  = "FloatLE"
-  show FloatBE  = "FloatBE"
-  show DoubleLE = "DoubleLE"
-  show DoubleBE = "DoubleBE"
-
--- | Creates a new buffer of the specified size.
-foreign import create :: Int -> Effect Buffer
-
--- | Creates a new buffer from an array of octets, sized to match the array.
-foreign import fromArray :: Array Octet -> Effect Buffer
-
--- | Creates a buffer view from a JS ArrayByffer without copying data.
---
--- Requires Node >= v5.10.0
-foreign import fromArrayBuffer :: ArrayBuffer -> Effect Buffer
-
--- | Creates a new buffer from a string with the specified encoding, sized to
--- | match the string.
-fromString :: String -> Encoding -> Effect Buffer
-fromString str = fromStringImpl str <<< encodingToNode
-
-foreign import fromStringImpl :: String -> String -> Effect Buffer
-
-foreign import toArrayBuffer :: Buffer -> Effect ArrayBuffer
-
--- | Reads a numeric value from a buffer at the specified offset.
-read :: BufferValueType -> Offset -> Buffer -> Effect Int
-read = readImpl <<< show
-
-foreign import readImpl :: String -> Offset -> Buffer -> Effect Int
-
--- | Reads a section of a buffer as a string with the specified encoding.
-readString :: Encoding -> Offset -> Offset -> Buffer -> Effect String
-readString = readStringImpl <<< encodingToNode
-
-foreign import readStringImpl ::
-  String -> Offset -> Offset -> Buffer -> Effect String
-
--- | Reads the buffer as a string with the specified encoding.
-toString :: Encoding -> Buffer -> Effect String
-toString = toStringImpl <<< encodingToNode
-
-foreign import toStringImpl :: String -> Buffer -> Effect String
-
--- | Writes a numeric value to a buffer at the specified offset.
-write :: BufferValueType -> Int -> Offset -> Buffer -> Effect Unit
-write = writeImpl <<< show
-
-foreign import writeImpl :: String -> Int -> Offset -> Buffer -> Effect Unit
-
--- | Writes octets from a string to a buffer at the specified offset. Multi-byte
--- | characters will not be written to the buffer if there is not enough capacity
--- | to write them fully. The number of bytes written is returned.
-writeString :: Encoding -> Offset -> Int -> String -> Buffer -> Effect Int
-writeString = writeStringImpl <<< encodingToNode
-
-foreign import writeStringImpl ::
-  String -> Offset -> Int -> String -> Buffer -> Effect Int
-
--- | Creates an array of octets from a buffer's contents.
-foreign import toArray :: Buffer -> Effect (Array Octet)
-
--- | Reads an octet from a buffer at the specified offset.
-getAtOffset :: Offset -> Buffer -> Effect (Maybe Octet)
-getAtOffset = getAtOffsetImpl Just Nothing
-
-foreign import getAtOffsetImpl ::
-  (Octet -> Maybe Octet) -> Maybe Octet -> Offset -> Buffer -> Effect (Maybe Octet)
-
--- | Writes an octet in the buffer at the specified offset.
-foreign import setAtOffset :: Octet -> Offset -> Buffer -> Effect Unit
-
--- | Returns the size of a buffer.
-foreign import size :: Buffer -> Effect Int
-
--- | Concatenates a list of buffers.
-foreign import concat :: Array Buffer -> Effect Buffer
-
--- | Concatenates a list of buffers, combining them into a new buffer of the
--- | specified length.
-foreign import concat' :: Array Buffer -> Int -> Effect Buffer
-
--- | Copies a section of a source buffer into a target buffer at the specified
--- | offset, and returns the number of octets copied.
-foreign import copy :: Offset -> Offset -> Buffer -> Offset -> Buffer -> Effect Int
-
--- | Fills a range in a buffer with the specified octet.
-foreign import fill ::
-  Octet -> Offset -> Offset -> Buffer -> Effect Unit
+instance mutableBufferEffect :: MutableBuffer Buffer Effect where
+  create = Internal.create
+  freeze = Internal.copyAll
+  unsafeFreeze = Internal.unsafeFreeze
+  thaw = Internal.copyAll
+  unsafeThaw = Internal.unsafeThaw
+  fromArray = Internal.fromArray
+  fromString = Internal.fromString
+  fromArrayBuffer = Internal.fromArrayBuffer
+  toArrayBuffer = Internal.toArrayBuffer
+  read = Internal.read
+  readString = Internal.readString
+  toString = Internal.toString
+  write = Internal.write
+  writeString = Internal.writeString
+  toArray = Internal.toArray
+  getAtOffset = Internal.getAtOffset
+  setAtOffset = Internal.setAtOffset
+  slice = Internal.slice
+  size = Internal.size
+  concat = Internal.concat
+  concat' = Internal.concat'
+  copy = Internal.copy
+  fill = Internal.fill