/wepl

A repl for WebAssembly Components

Primary LanguageRust

WEPL

The WebAssembly Component repl.

Example

$ wepl mycomponent.wasm
> .exports
uppercase: func(input: string) -> string
> uppercase
uppercase: func(input: string) -> string
> s = "hello"
s: string
> uppercase(s)
"HELLO"

Built-in Functions

Built-in functions can be called by using the . prefix.

Supported functions include:

  • .imports: print a list of all the component's imports
  • .exports: print a list of all the component's exports
  • .link $function $wasm: satisfy the imported function $func with an export from the wasm component $wasm
  • .compose $adapter: satisfy imports with the supplied adapter module (e.g., to compose with WASI-Virt adapter)
  • .type $type: inspect a type's $type definition in scope
  • .help: print help information (? is alias for this built-in)

Features

  • Exported function evaluation
  • Listing imports and exports
  • Variable assignment
  • Type checking
  • Satisfying imports with other WebAssembly Components
  • Basic component composition

Compatibility

wepl is currently tied to the wasmtime 13 release. Components that work with that release should work in wepl.