The following environment variables are recognized when run from the command line. The same environment variables are available for the JavaScript, Python and Java targets.
To choose the colour scheme of the terminal, use the TERM_SCHEME variable. The only recognized value is ‘dark’, all other values or absence of the variable gives ‘light‘:
TERM_SCHEME=dark # Dark mode
The environment variable is mapped to the Prolog flag sys_color upon start. This Prolog flag then controls the behaviour of library(markup) in the output has ASCII modus.