This commit introduces a new feature called `"regex"`. It adds a new
function `validator_regex` to `Arg` and was inspired by the discussion
in #1968. The name `validator_regex` was chosen instead of
`regex_validator` to make sure that the developer keeps in mind that
there may only be a single `Validator` on an `Arg`.
The feature can be used with YAML files, however there is no proper
pattern in `clap_app!` (yet).
While reading the code for the yaml translation, I've noticed that
there is a bug in the macro `yaml_opt_str` as well as a wrong `null`
value in the test fixture.
These tests add the expected behaviour on the given fixture, e.g.
prog
and
prog <WRONG>
where `<WRONG>` is **not** `other` should yield `None` for
`"positional2"`, whereas
prog other
should yield "something" and
prog --flag ARBITRARY_VALUE
should yield "some". The first two tests
- default_value_if_not_triggered
- default_value_if_not_triggered_by_argument
fail, as the second positional arguments *gets set*, although its
conditions aren't fulfilled.
Adds new method/attribute `Arg::value_hint`, taking a `ValueHint` enum
as argument. The hint can denote accepted values, for example: paths,
usernames, hostnames, commands, etc.
This initial implementation supports hints for the zsh and fish
completion generators, support for other shells can be added later.
this implements Arg::short_alias, Arg::short_aliases,
Arg::short_visible_alias, and Arg::short_visible_aliases in addition to
adding their associated tests
