* installing *source* package ‘mathml’ ...
** this is package ‘mathml’ version ‘1.7’
** package ‘mathml’ successfully unpacked and MD5 sums checked
** using staged installation
** R
** inst
** byte-compile and prepare package for lazy loading
Warning message:
In rolog_ok(warn = TRUE) : This package requires the SWI-Prolog runtime.

If SWI-Prolog is not on your system
- You can install SWI-Prolog from https://swi-prolog.org.
- Alternatively, install the R package rswipl.

If SWI-Prolog has been installed on your system
- Please add swipl to the PATH.
- Alternatively, let the environment variable SWI_HOME_DIR point to the correct folder.
** help
*** installing help indices
** building package indices
** installing vignettes
** testing if installed package can be loaded from temporary location
Warning in rolog_ok(warn = TRUE) :
  This package requires the SWI-Prolog runtime.

If SWI-Prolog is not on your system
- You can install SWI-Prolog from https://swi-prolog.org.
- Alternatively, install the R package rswipl.

If SWI-Prolog has been installed on your system
- Please add swipl to the PATH.
- Alternatively, let the environment variable SWI_HOME_DIR point to the correct folder.
Error: package or namespace load failed for ‘mathml’:
 .onAttach failed in attachNamespace() for 'mathml', details:
  call: fun(libname, pkgname)
  error: Could not attach R package rolog.
Error: loading failed
Execution halted
ERROR: loading failed
* removing ‘/Volumes/Builds/packages/big-sur-x86_64/results/4.6/mathml.Rcheck/mathml’