https://github.com/kritzcreek/purescript-wasm

Wasm library for PureScript
https://github.com/kritzcreek/purescript-wasm

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Wasm library for PureScript

• Host: GitHub
• URL: https://github.com/kritzcreek/purescript-wasm
• Owner: kritzcreek
• License: apache-2.0
• Created: 2020-10-31T00:02:34.000Z (about 4 years ago)
• Default Branch: main
• Last Pushed: 2024-08-02T05:12:47.000Z (3 months ago)
• Last Synced: 2024-10-11T23:54:53.678Z (26 days ago)
• Language: PureScript
• Size: 93.8 KB
• Stars: 26
• Watchers: 5
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
purescript-wasm

===

A PureScript library containing syntax definitions and encoders for WebAssembly. You can use this to generate Wasm for your own compiler projects. This library does *not* compile PureScript to Wasm.

## Minimal example

As a small example we'll define a module with a `main` function that takes no arguments and returns an i32. It'll add the numbers 20 and 22 and return 42 as its result. I'll include a bit of FFI to instantiate and run the generated Wasm.

```purescript

module Main where

import Prelude

import Data.ArrayBuffer.Types (Uint8Array)

import Effect (Effect)

import Wasm.Encode as Encode

import Wasm.Syntax as S

foreign import execWasm :: Uint8Array -> Effect Unit

wasmModule :: S.Module

wasmModule = S.emptyModule

  { types = [ { arguments: [], results: [ S.NumType S.I32 ] } ]

  , funcs = [ { locals: [], type: 0, body: [ S.I32Const 20, S.I32Const 22, S.I32Add ] } ]

  , exports = [ { name: "main", desc: S.ExportFunc 0 } ]

  }

main :: Effect Unit

main = do

  let bytes = Encode.encodeModule wasmModule

  execWasm bytes

```

```javascript

export const execWasm = (bytes) => () => {

  WebAssembly.instantiate(bytes, {})

    .then(module => console.log(module.instance.exports.main()))

}

```

For a real compiler project you'll likely want to define your own builder on top of `Wasm.Syntax` to keep track of indices for you. An example of this can be seen in `example/src/WasmBuilder.purs`.