This reverts commit a67a0436f7, reversing
changes made to 9965df76d0.
This commit or the earlier commit this commit is based on (#40531) broke the
incremental bot.
Update the lexing implementation to defer to the
regex library, which will pass back the pointer
from to resume lexing, and update the emission to
call the new `Regex(_regexString:version:)`
overload, that will accept the regex string with
delimiters.
Because this uses the library's lexing
implementation, the delimiters are now `'/.../'`
and `'|...|'` instead of plain `'...'`.
- Frontend: Implicitly import `_StringProcessing` when frontend flag `-enable-experimental-string-processing` is set.
- Type checker: Set a regex literal expression's type as `_StringProcessing.Regex<(Substring, DynamicCaptures)>`. `(Substring, DynamicCaptures)` is a temporary `Match` type that will help get us to an end-to-end working system. This will be replaced by actual type inference based a regex's pattern in a follow-up patch (soon).
- SILGen: Lower a regex literal expression to a call to `_StringProcessing.Regex.init(_regexString:)`.
- String processing runtime: Add `Regex`, `DynamicCaptures` (matching actual APIs in apple/swift-experimental-string-processing), and `Regex(_regexString:)`.
Upcoming:
- Build `_MatchingEngine` and `_StringProcessing` modules with sources from apple/swift-experimental-string-processing.
- Replace `DynamicCaptures` with inferred capture types.
