Specifications of flexmodel objects often
involves string manipulations with regular expressions,
and these functions provide some convenience in this area.
alt_group(x, exact = FALSE, negate = FALSE)
wrap_exact(x)
all_in(x)
any_var(x)
all_except(x)character vector to convert into a length-1 character vector representing a regular expression pattern
should the regular expression look for exact matches?
should the regular expression look for stings that do not match?
a regular expression pattern to be used in functions
like grep and grepl, but also in
add_state_param_sum