Resolve argument value when aliases are used (generic ggDNAvis helper)

See the aliases page for a general explanation of how aliases are used in ggDNAvis.

This function takes the name and value for the 'primary' form of an argument (generally British spellings in ggDNAvis), the name and value of an alternative 'alias' form, and the default value of the 'primary' argument.

If the alias has not been used (i.e. the 'alias' value is NULL) or if the 'primary' value has been changed from the default, then the 'primary' value will be returned. (Note that if the 'alias' value is not NULL and the 'primary' value has been changed from the default, then the updated 'primary' value 'wins' and is returned, but with a warning that explains that both values were set and the 'alias' has been discarded).

If the alias has been used (i.e. the 'alias' value is not NULL) and the 'primary' value is the default, then the 'alias' value will be returned.

Usage

resolve_alias(
  primary_name,
  primary_val,
  alias_name,
  alias_val,
  primary_default
)

Arguments

primary_name

character. The usual name of the argument.

primary_val

value. The value of the argument under its usual name.

alias_name

character. An alternative alias name for the argument.

alias_val

value. The value of the argument under its alias. Expected to be NULL if the alias argument is not being used.

primary_default

value. The default value of the argument under its usual name, used to determine if the primary argument has been explicitly set.

Value

value. Either primary_val or alias_val, depending on the logic above.