Rstan and Stan 2.20.0

Why is CRAN difficult?
I have been trying to install it from source, however that is not very easy.

  • Why do I have to install V8 ? a full javascript engine seems a little overkill for rstan.
  • I am currently stuck at installing StanHeaders using the install_StanHeaders() function in the “install-github.R” file. I get:

Error: package or namespace load failed for ‘StanHeaders’:
.onAttach failed in attachNamespace() for ‘StanHeaders’, details:
call: system.file(“include”, “stan”, “math”, “prim”, “mat”, “fun”,
error: no file found

Can someone help point me in the right direction, please?