Command.Anons
SourceAnonymous command-line argument specification.
A specification of some number of anonymous arguments.
(name %: typ)
specifies a required anonymous argument of type typ
.
The name
must not be surrounded by whitespace; if it is, an exn will be raised.
If the name
is surrounded by a special character pair (<>, {}, [] or (),) name
will remain as-is, otherwise, name
will be uppercased.
In the situation where name
is only prefixed or only suffixed by one of the special character pairs, or different pairs are used (e.g., "<ARG]"), an exn will be raised.
The (possibly transformed) name
is mentioned in the generated help for the command.
sequence anons
specifies a sequence of anonymous arguments. An exception will be raised if anons
matches anything other than a fixed number of anonymous arguments.
non_empty_sequence_as_pair anons
and non_empty_sequence_as_list anons
are like sequence anons
except that an exception will be raised if there is not at least one anonymous argument given.
(maybe anons)
indicates that some anonymous arguments are optional.
(maybe_with_default default anons)
indicates an optional anonymous argument with a default value.
t2
, t3
, and t4
each concatenate multiple anonymous argument specs into a single one. The purpose of these combinators is to allow for optional sequences of anonymous arguments. Consider a command with usage:
main.exe FOO [BAR BAZ]
where the second and third anonymous arguments must either both be there or both not be there. This can be expressed as:
t2 ("FOO" %: foo) (maybe (t2 ("BAR" %: bar) ("BAZ" %: baz)))]
Sequences of 5 or more anonymous arguments can be built up using nested tuples:
maybe (t3 a b (t3 c d e))