mjs

This implementation is nuts. A decent chunk (but still very small subset) of ES5 in a single file, under 1400 lines of very readable C code. It includes a mark-and-sweep GC and an FFI. It doesn't have an AST or a bytecode VM. It just interprets directly off of source code. Take a look: https://github.com/cesanta/elk/blob/master/elk.c. The first time I scanned through the file and thought there was nothing there. It does an entire implementation in the same amount of code that most implementations do a parser alone (but yes, it implements way less than a 100% spec compliant parser does). This implementation really sets a new bar for me in terms of compact-but-readable language implementations. Separately, this isn't even Cesanta's only embedded JavaScript implementation. They also have: https://github.com/cesanta/mjs. mjs is a bit more com

FYI: mJS is most likely https://github.com/cesanta/mjs. It can be hard to search for because .mjs is also a file extension for JS modules.

Looks like it's similarly named: https://github.com/cesanta/mjs

Edit: Apparently this project is a JS interpreter for C++ ... while mJS that I wrote about is a JS interpreter for... C and C++ The one I was talking about is https://github.com/cesanta/mjs ... yea, two JS interpreters for C++ with the same name. How could that be confusing?

Similar projects https://github.com/cesanta/v7 And https://github.com/cesanta/mjs

Is this a re-packaged v7 [0] (it's from Cesanta as well)? mjs.c is 477K. It looks like it as v7.c is 475K [1]. It shaves whole entire 1MB from my staticly linked builds (v7 1.9MB vs. mjs 998K), and almost 2MB from dynamically linked builds (v7 1.9MB vs. mjs 99K) on amd64. If it shares the same underlying architecture and api [2] then this is a pretty great achievement. In their docs, they claim 25K storage and 10K RAM. Blog post claims 25K storage and 1K RAM. [0] https://github.com/cesanta/mjs/blob/master/mjs.c [1] https://github.com/cesanta/v7/blob/master/v7.c [2] https://docs.cesanta.com/v7/master/#/v7-internals/