# Valid names a1_foo, A1_FOO, .foo_, ._foo, Bar.42, foo..1, ., ._, .., ..., ..1, c, T, F, ._1 # Reserved Words NA, NA_integer_, NA_real_, NA_character_, NA_complex_, NULL, NaN, Inf # Keywords function, while, repeat, for, if, in, else, next, break # Not reserved NULLa, NULL1, NULL., `NULL`, 'NULL', NA_foo_, na_real_, Function, for. # Primitive built-ins return, switch, sum # Non-primitive base functions stop, try # Quoted identifiers `+` `%*%` `a 10 b` `for` `# x` `\`b` `\\` `%\`%` # Invalid names (for reference) # 0abc, .0abc, abc+cde, _, _., _x, _1, .1_