WEPL

The WebAssembly Component repl.

Building from Source

You can build wepl from source by running cargo build --release (or cargo build to build in debug mode).

Installing wepl

You can install wepl from crates.io by running cargo install wepl --locked.

You can also install wepl on your local system by running cargo install --path . --locked.

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 17 release. Components that work with that release should work in wepl.