The S3 methods for edbl_fct objects have
the same expected output that of a factor.
Other functions are utility functions related to edbl_fct object.
Usage
# S3 method for edbl_fct
as.character(x, ...)
# S3 method for edbl_fct
as.integer(x, ...)
is_fct(x)
is_unit(x)
is_trt(x)
is_rcrd(x)