How to see the specific info of a function in a R package

[Yanni]

I want to see the specific information of a function in a R package written by others.
But when I put it in R, I can only get:

function (Y, X)
{
.Call(_xxxx_BpLS, Y, X)
}
where "XXXX" is the package name.

[AlexisW]

That means the actual function was written in C or C++, you can't read it inside R.

If you go to the CRAN page, for example with dplyr, you can find the Package source at the bottom (dplyr_1.0.2.tar.gz), if you download and open it, you can find the C++ code in the src subdirectory.

On the CRAN page, you also see a link to dplyr's github page in the BugReports and URL fields, which may be an easier way to find the code. If these fields do not have any github/gitlab/bitbucket link, it might still be useful to make a direct search on Github.

PS: note that if you're not familiar with C/C++, the source code may be very hard to read and understand.