Adds modules for internal, external, and dynamic commands, as well as
the pipeline functionality. These are exported as their old names from
the classified module so as to keep its "interface" the same.
`left =~ right` return true if left contains right, using Rust's
`String::contains`. `!~` is the negated version.
A new `apply_operator` function is added which decouples evaluation from
`Value::compare`. This returns a `Value` and opens the door to
implementing `+` for example, though it wouldn't be useful immediately.
The `operator!` macro had to be changed slightly as it would choke on
`~` in arguments.
This commit extracts five new crates:
- nu-source, which contains the core source-code handling logic in Nu,
including Text, Span, and also the pretty.rs-based debug logic
- nu-parser, which is the parser and expander logic
- nu-protocol, which is the bulk of the types and basic conveniences
used by plugins
- nu-errors, which contains ShellError, ParseError and error handling
conveniences
- nu-textview, which is the textview plugin extracted into a crate
One of the major consequences of this refactor is that it's no longer
possible to `impl X for Spanned<Y>` outside of the `nu-source` crate, so
a lot of types became more concrete (Value became a concrete type
instead of Spanned<Value>, for example).
This also turned a number of inherent methods in the main nu crate into
plain functions (impl Value {} became a bunch of functions in the
`value` namespace in `crate::data::value`).
This was achieved by deleting Cargo.lock
and letting a recent Cargo nightly re-create
it. Support for the format was already
introduced in Rust 1.38, but currently,
stable releases of Cargo only retain it
if encountered but don't generate such
files by default.
The new format is smaller, better suited to
prevent merge conflicts and generates smaller
diffs at dependency updates, leading to
smaller git history.
You can read more about it in this PR: https://github.com/rust-lang/cargo/pull/7070
