Miscellany

as_string(x)

Convert a value to a string appropriate for use as a command option value. This helper is primarily used by the ShortOption and LongOption constructors, which delegate to as_string to normalize their value argument.

The following behaviors are supported:

• scalars – anything not matching the other methods is passed through string (e.g. numbers, custom types).
• strings – if the value is already an AbstractString it is returned unchanged.
• vectors – elements are joined with commas, yielding a single comma‑separated string.
• tuples – the tuple’s values are joined with commas as well (useful for short options like -O in examples below).

Examples

julia> as_string(3)
"3"
julia> as_string([1,2,3])
"1,2,3"
julia> as_string(("a","b"))
"a,b"

Users may extend as_string for their own custom types by defining additional methods; this is the recommended way to make the option-values conversion behave appropriately for specialized data structures.