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bfa02fd418
This ports our example testing over to [trycmd](https://docs.rs/) so we can: - More thoroughly test our examples - Provide always-up-to-date example usage The old way of testing automatically picked up examples. This new way requires we have a `.md` file that uses the example in some way. Notes: - Moved overall example description to the `.md` file - I added cross-linking between related examples - `14_groups` had a redundant paragraph (twice talked about "one and only one"
1.5 KiB
1.5 KiB
Of the three argument types, flags are the most simple. Flags are simple switches which can be either "on" or "off"
clap also supports multiple occurrences of flags, the common example is "verbosity" where a
user could want a little information with "-v" or tons of information with "-v -v" or "-vv"
Let's look at their help:
$ 05_flag_args --help
MyApp
USAGE:
05_flag_args[EXE] [OPTIONS] [output]
ARGS:
<output> sets an output file
OPTIONS:
-a, --awesome turns up the awesome
-c, --config <FILE> sets a custom config file
-h, --help Print help information
By default, nothing happens:
$ 05_flag_args
Nothing is awesome
Note that --awesome places requirements on how other flags are used:
$ 05_flag_args --awesome
? failed
error: The following required arguments were not provided:
--config <FILE>
USAGE:
05_flag_args[EXE] --config <FILE> --awesome
For more information try --help
$ 05_flag_args output.txt --config file.toml --awesome
? failed
error: The argument '--awesome' cannot be used with '<output>'
USAGE:
05_flag_args[EXE] --config <FILE> <output>
For more information try --help
You can then add --awesome as many times as you like:
$ 05_flag_args --config file.toml --awesome
Awesomeness is turned on
Some things are awesome
$ 05_flag_args --config file.toml --awesome --awesome
Awesomeness is turned on
Lots of things are awesome
$ 05_flag_args --config file.toml -aaaaaaaaaaaaaaaaaa
Awesomeness is turned on
EVERYTHING is awesome!