Bare words now represent literal file names, and globs are a different
syntax shape called "Pattern". This allows commands like `cp` to ask for
a pattern as a source and a literal file as a target.
This also means that attempting to pass a glob to a command that expects
a literal path will produce an error.
Previously, there was a single parsing rule for "bare words" that
applied to both internal and external commands.
This meant that, because `cargo +nightly` needed to work, we needed to
add `+` as a valid character in bare words.
The number of characters continued to grow, and the situation was
becoming untenable. The current strategy would eventually eat up all
syntax and make it impossible to add syntax like `@foo` to internal
commands.
This patch significantly restricts bare words and introduces a new token
type (`ExternalWord`). An `ExternalWord` expands to an error in the
internal syntax, but expands to a bare word in the external syntax.
`ExternalWords` are highlighted in grey in the shell.
At the moment the pipeline parser does not enforce
that there must be a pipe between each part of the pipeline,
which can lead to confusing behaviour or misleading errors.
This commit is more substantial than it looks: there was basically no
real support for decimals before, and that impacted values all the way
through.
I also made Size contain a decimal instead of an integer (`1.6kb` is a
reasonable thing to type), which impacted a bunch of code.
The biggest impact of this commit is that it creates many more possible
ways for valid nu types to fail to serialize as toml, json, etc. which
typically can't support the full range of Decimal (or Bigint, which I
also think we should support). This commit makes to-toml fallible, and a
similar effort is necessary for the rest of the serializations.
We also need to figure out how to clearly communicate to users what has
happened, but failing to serialize to toml seems clearly superior to me
than weird errors in basic math operations.
This commit makes it possible to force nu to treat a command as an external command by prefixing it with `^`. For example `^dir` will force `dir` to run an external command, even if `dir` is also a registered nu command.
This ensures that users don't need to leave nu just because we happened to use a command they need.
This commit adds a new token type for external commands, which, among other things, makes it pretty straight forward to syntax highlight external commands uniquely, and generally to treat them as special.
