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81 lines
1.3 KiB
Markdown
81 lines
1.3 KiB
Markdown
These are cases which could be detected by `clap`, and potentially warn at compile time. Maybe even with a nice web URL to more info.
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# Abrv. Syntax
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First, a little about the syntax to understand the setup of rule. This syntax will make each rule more concise so we don't have to write an entire `clap` definition.
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## Arg Types
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* `--opt` is an option
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* `--flag` is a flag
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* `#` (i.e. `1` or `2`) is a positional argument
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* `val` is an option value
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## Modifiers
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Can be used on `val` or Arg types
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* `*`: zero or more
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* `+`: one or more
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* `?`: zero or one
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* `{#,#}`: # to # times (i.e. `{1,4}` is one to four times)
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* `<>`: required
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* `=`: requires equals
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* Ends in `,`: requires delimiter
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* `(foo,bar)`: values can only be `foo` or `bar`
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# --opt val? 1
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## Ambiguous Uses
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```
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$ prog --opt foo
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# is foo option val or positional?
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```
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## Non-Ambiguous Uses
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```
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$ prog 1 --opt
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$ prog --opt -- 1
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```
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## Fixes
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### Require equals on `--opt`
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```
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$ prog --opt foo
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# foo is positional
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$ prog --opt=val foo
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```
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# --opt val+ 1
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## Ambiguous Uses
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```
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$ prog --opt foo bar
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# is bar option val or positional?
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```
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## Non-Ambiguous Uses
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```
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$ prog 1 --opt val
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$ prog --opt val -- 1
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```
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## Fixes
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### `--opt` only one val per occurrence
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```
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$ prog --opt foo bar
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# bar is positional
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$ prog --opt val bar --opt foo
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# bar is positional
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```
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