[Rd] Feature request: adding a log.p= option to stats::p.adjust?

[Aaron Lun]

Dear list,

Is there any interest in adding a log.p= option to p.adjust() so that it 
can accept log-transformed p-values and return log-transformed adjusted 
p-values?

I have some functions that, on occasion, return very low p-values. To 
avoid underflow in such cases, I allow my users to set log.p=TRUE, which 
is passed onto pt(), pchisq(), etc. to return log-transformed p-values. 
However, currently, these log-p-values need to be run through exp() 
before being used in p.adjust(). This re-introduces the possibility of 
underflow errors, sometimes leading to adjusted p-values of zero.

The proposed log.p= mode for p.adjust() would perform all operations in 
the log-scale to avoid this - see 
https://github.com/MarioniLab/scran/blob/f9ace20d74c7fdbde613aaf91311cdfc6dbe0feb/R/utils_markers.R#L184-L190 
for an example with the BH correction. If it were available, we could 
conveniently pass along the log.p=TRUE option to p.adjust() as we do for 
pt() and friends, and everything would "just work".

If this sounds sensible, I would be happy to put a patch together; the 
modifications involved seem simple enough.

Best,

Aaron