This is an initial attempt at migrating grep-searcher to use the new
bstr crate (not yet published).
This is mostly an improvement, although a significant problem is that
the grep-matcher crate controls the `Index` impls for the `Match` type,
which we use quite heavily. Thus, in order to impl `Index` for `BStr`,
we need add bstr as a public dependency to grep-matcher. This is really
bad news because grep-matcher is supposed to be a light-weight core
crate that defines a matcher interface, which is itself intended to be a
public dependency. Thus, a semver bump on bstr will have very
undesirable ripple effects thoughout ripgrep's library crates.
This would be something we could stomach if bstr was solid at 1.0 and
committed to avoiding breaking changes. But it's not there yet.
libripgrep is not any one library, but rather, a collection of libraries
that roughly separate the following key distinct phases in a grep
implementation:
1. Pattern matching (e.g., by a regex engine).
2. Searching a file using a pattern matcher.
3. Printing results.
Ultimately, both (1) and (3) are defined by de-coupled interfaces, of
which there may be multiple implementations. Namely, (1) is satisfied by
the `Matcher` trait in the `grep-matcher` crate and (3) is satisfied by
the `Sink` trait in the `grep2` crate. The searcher (2) ties everything
together and finds results using a matcher and reports those results
using a `Sink` implementation.
Closes#162
