if else repeat while
function for in
next break
TRUE FALSE NULL
Inf NaN
NA NA_integer_ NA_real_
NA_complex_ NA_character_
... and ..1, ..2 etc, which are used to refer to
arguments passed down from a calling function. See the
/doc/manual/R-intro.html#The-three-dots-argumentIntroduction to R
manual for usage of these syntactic elements,
and dotsMethods for their use in formal methods.
make.names). They are allowed as non-syntactic
names, e.g. inside backtick quotes.