search for: do_tild

...fitting functions (e.g., for split-apply). One could argue that today data frames and formulae go hand in hand, and that the lack of is.formula() is a rather ugly asymmetry ... Furthermore, 'formula' is one of the only S3 classes generated by way of a primitive (the `~` operator, calling do_tilde() in names.c), so it is really in some sense "special" { compared to 'factor', 'POSIXlt', etc. }. What do people think? In case it helps, I've gathered some data from 'base' and the so-called 'defaultPackages', reproduced by the attached R script ......