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https://github.com/clap-rs/clap
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31 lines
748 B
Markdown
31 lines
748 B
Markdown
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Using `Arg::default_value`, rather than `Option::unwrap_or`, gives clap more information it can use with our argument.
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For example, let's look at the help:
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```bash
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$ 10_default_values --help
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myapp
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does awesome things
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USAGE:
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10_default_values[EXE] [OPTIONS] [INPUT]
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ARGS:
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<INPUT> The input file to use [default: input.txt]
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OPTIONS:
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-c <CONFIG> The config file to use
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-h, --help Print help information
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```
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`<INPUT>`'s description says what the default is while `-c`'s does not.
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Otherwise, they'll work the same:
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```bash
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$ 10_default_values
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The input file is: input.txt
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The config file is: config.json
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$ 10_default_values other.txt -c other.toml
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The input file is: other.txt
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The config file is: other.toml
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```
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