feat: Expose clap_lex #3635
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feat: Expose clap_lex #3635
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Before, we had a generic `next` that provided the next item and peeked at all remaining items. This was to work around the borrow checker for modifying the position while accessing args. We've now split `Input` into `RawArgs` and `ArgsCursor` so we don't have overlapping borrows. This made it so we can split `next` into `next`, `peek`, and `remaining`.
Since we'll need `skip`, it made me wonder how to name `skip` and `previous` to fit together, so I decided to play with `seek`. Its probably over kill but wondering if its better.
The lexer will soon return `RawOsStr` and it'll cost to turn that into an `OsStr`. However, it caches a `str`, so let's just use that.
In considering the design for this, we want: - Ability to modify the argment list while maintaining the `Cursor` for replacements - Allow picking up subcommand parsing in the middle of short flags - Ability to peek at the next item to determine if we want to treat it as a flag or as a value - Ability to detect started short and long arguments for completions Longer term, we also want to consider: - Allowing users to customize the lexer to support different syntaxes
While figuring out the API, `clap_lex` was tested by clap's tests. Now we are focusing on its API directly.
This tempts me to drop our design philosophy but I want to give it more time.
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This splits out a
clap_lex, somewhat inspired bylexopt. The main difference is thatlexoptmanages all state in one object while we have to split out the state to support:This was also done with an eye towards rust-driven completions. This will let the completion engine reuse the same lexer. The parsers will be different for now but as we learn more about a completion parser, we can look to see if and how we can use the same parser between the two. One side effect of this is that we treat
--as potentially a long and-as potentially a short. The problem with this approach is we aren't treating-as a long as well because there is nothing good for us to return. We might need to reconsider that approach due to the inconsistency.Benefits of factoring out
clap_lex:Deferred:
---long) #3309, Support non-Unix options (e.g. find -exec, bash +O shopt, cmd.exe /c, gcc -Wl,) #2468: Ideally we simplify things down to support aBox<dyn Lexer>which will require some work redesigning the API to take this into accountFixes #2915