# Rstan and Stan 2.20.0

**URL:** <https://discourse.mc-stan.org/t/rstan-and-stan-2-20-0/13486>\
**Category:** RStan\
**Tags:** rstan\
**Created:** [March 3, 2020, 1:51pm UTC](https://discourse.mc-stan.org/t/rstan-and-stan-2-20-0/13486 "2020-03-03T13:51:12Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![Stephen\_Martin](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/stephen_martin/32/7879_2.png) [@Stephen\_Martin](https://discourse.mc-stan.org/u/Stephen_Martin)\
**Post date:** [March 6, 2020, 2:06am UTC](https://discourse.mc-stan.org/t/rstan-and-stan-2-20-0/13486/5 "2020-03-06T02:06:42Z")

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Wait, so the stanc3 parser (written in OCaml) also has a javascript version?

Edit:  
Oh wow, didn’t see this before: [A javascript stanc3](https://discourse.mc-stan.org/t/a-javascript-stanc3/11044/12)

Interesting. So for future rstan releases, the ocaml parser is compiled from OCaml to javascript, and then the js parser is used by rstan to create the C++? That’s crazy, in the best way. I understand the reason (OCaml dependencies are certainly harder to manage than a single js engine), I’m just surprised it works at all.

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