The excellent Nom library was used to build the parser. The interpreter itself has no external dependencies.
By way of an example, linked is a live demo of the parser and interpreter compiled to a WASM module, allowing scripts to be parsed and executed entirely within the browser.
The project is mainly a component of another project that I'm working on, but I thought that some of you might be interested in the progress so far. Everything's open source, so please take a look at the code too (GitHub link on page). I'm planning on writing a tutorial series about this too, so I'll post a link to that when it's available.
Thanks!