* fix#4161
println! and friends will panic on BrokenPipe. The solution is to use
writeln! instead, and ignore the error (or do we want to do something else?)
* test that nu doesn't panic in case of BrokenPipe error
* fixup! test that nu doesn't panic in case of BrokenPipe error
* make do_not_panic_if_broken_pipe only run on UNIX systems
* fix#4140
We are passing commands into a shell underneath but we were not
escaping arguments correctly. This new version of the code also takes
into consideration the ";" and "&" characters, which have special
meaning in shells.
We would probably benefit from a more robust way to join arguments to
shell programs. Python's stdlib has shlex.join, and perhaps we can
take that implementation as a reference.
* clean up escaping of posix shell args
I believe the right place to do escaping of arguments was in the
spawn_sh_command function. Note that this change prevents things like:
^echo "$(ls)"
from executing the ls command. Instead, this will just print
$(ls)
The regex has been taken from the python stdlib implementation of shlex.quote
* fix non-literal parameters and single quotes
* address clippy's comments
* fixup! address clippy's comments
* test that subshell commands are sanitized properly
```
> [
[ msg, labels, span];
["The message", "Helpful message here", ([[start, end]; [0, 141]])]
] | error make
error: The message
┌─ shell:1:1
│
1 │ ╭ [
2 │ │ [ msg, labels, span];
3 │ │ ["The message", "Helpful message here", ([[start, end]; [0, 141]])]
│ ╰─────────────────────────────────────────────────────────────────────^ Helpful message here
```
Adding a more flexible approach for creating error values. One use case, for instance is the
idea of a test framework. A failed assertion instead of printing to the screen it could create
tables with more details of the failed assertion and pass it to this command for making a full
fledge error that Nu can show. This can (and should) be extended for capturing error values as well
in the pipeline. One could also use it for inspection.
For example: `.... | error inspect { # inspection here }`
or "error handling" as well, like so: `.... | error capture { fix here }`
However, we start here only with `error make` that creates an error value for you with limited support for the time being.
* Resolve rebase artifacts
* Remove leftover dependencies on removed feature
* Remove unnecessary 'pub'
* Start taking notes and fooling around
* Split canonicalize to two versions; Add TODOs
One that takes `relative_to` and one that doesn't.
More TODO notes.
* Merge absolutize to and rename resolve_dots
* Add custom absolutize fn and use it in path expand
* Convert a couple of dunce::canonicalize to ours
* Update nu-path description
* Replace all canonicalize with nu-path version
* Remove leftover dunce dependencies
* Fix broken autocd with trailing slash
Trailing slash is preserved *only* in paths that do not contain "." or
"..". This should be fixed in the future to cover all paths but for now
it at least covers basic cases.
* Use dunce::canonicalize for canonicalizing
* Alow cd recovery from non-existent cwd
* Disable removed canonicalize functionality tests
Remove unused import
* Break down nu-path into separate modules
* Remove unused public imports
* Remove abundant cow mapping
* Fix clippy warning
* Reformulate old canonicalize tests to expand_path
They wouldn't work with the new canonicalize.
* Canonicalize also ~ and ndots; Unify path joining
Also, add doc comments in nu_path::expansions.
* Add comment
* Avoid expanding ndots if path is not valid UTF-8
With this change, no lossy path->string conversion should happen in the
nu-path crate.
* Fmt
* Slight expand_tilde refactor; Add doc comments
* Start nu-path integration tests
* Add tests TODO
* Fix docstring typo
* Fix some doc strings
* Add README for nu-path crate
* Add a couple of canonicalize tests
* Add nu-path integration tests
* Add trim trailing slashes tests
* Update nu-path dependency
* Remove unused import
* Regenerate lockfile
* Allow different names for ...rest
* Resolves#3945
* This change requires an explicit name for the rest argument in `WholeStreamCommand`,
which is why there are so many changed files.
* Remove redundant clone
* Add tests
* Allow environment variables to be hidden
This change allows environment variables in Nushell to have a value of
`Nothing`, which can be set by the user by passing `$nothing` to
`let-env` and friends.
Environment variables with a value of Nothing behave as if they are not
set at all. This allows a user to shadow the value of an environment
variable in a parent scope, effectively removing it from their current
scope. This was not possible before, because a scope can not affect its
parent scopes.
This is a workaround for issues like #3920.
Additionally, this allows a user to simultaneously set, change and
remove multiple environment variables via `load-env`. Any environment
variables set to $nothing will be hidden and thus act as if they are
removed. This simplifies working with virtual environments, which rely
on setting multiple environment variables, including PATH, to specific
values, and remove/change them on deactivation.
One surprising behavior is that an environment variable set to $nothing
will act as if it is not set when querying it (via $nu.env.X), but it is
still possible to remove it entirely via `unlet-env`. If the same
environment variable is present in the parent scope, the value in the
parent scope will be visible to the user. This might be surprising
behavior to users who are not familiar with the implementation details.
An additional corner case is the the shorthand form of `with-env` does
not work with this feature. Using `X=$nothing` will set $nu.env.X to the
string "$nothing". The long-form works as expected: `with-env [X
$nothing] {...}`.
* Remove unused import
* Allow all primitives to be convert to strings
Some environment variables, such as `RUST_LOG` include equals signs. Nushell
should support this in the shorthand environment variable syntax so that
developers using these variables can control them easily. We accomplish this by
swapping `std::str::split` for `std::str::splitn`, which ensures that we only
consider the first equals sign in the string instead of all of them, which we
did previously.
Closes#3867
Added test cases that ensure that special characters in path names are passed
to external commands correctly. These cases have been implemented with rstest
to reuse existing test code.
* Add the load-env command
load-env can be used to add environment variables dynamically via an
InputStream. This allows developers to create tools that output environment
variables as key-value pairs, then have the user load those variables in using
load-env. This supplants most of the need for an `eval` command, which is
mostly used in POSIX envs for setting env vars.
Fixes#3481
* fixup! Add the load-env command
* Revert "History, more test coverage improvements, and refactorings. (#3217)"
This reverts commit 8fc8fc89aa.
* Add tests
* Refactor .nu-env
* Change logic of Config write to logic of read()
* Fix reload always appends to old vars
* Fix reload always takes last_modified of global config
* Add reload_config in evaluation context
* Reload config after writing to it in cfg set / cfg set_into
* Add --no-history to cli options
* Use --no-history in tests
* Add comment about maybe_print_errors
* Get ctrl_exit var from context.global_config
* Use context.global_config in command "config"
* Add Readme in engine how env vars are now handled
* Update docs from autoenv command
* Move history_path from engine to nu_data
* Move load history out of if
* No let before return
* Add import for indexmap
Improvements overall to Nu. Also among the changes here, we can also be more confident towards incorporating `3041`. End to end tests for checking envs properly exported to externals is not added here (since it's in the other PR)
A few things added in this PR (probably forgetting some too)
* no writes happen to history during test runs.
* environment syncing end to end coverage added.
* clean up / refactorings few areas.
* testing API for finer control (can write tests passing more than one pipeline)
* can pass environment variables in tests that nu will inherit when running.
* No longer needed.
* no longer under a module. No need to use super.
* Playground infraestructure (tests, etc) additions.
A few things to note:
* Nu can be started with a custom configuration file (`nu --config-file /path/to/sample_config.toml`). Useful for mocking the configuration on test runs.
* When given a custom configuration file Nu will save any changes to the file supplied appropiately.
* The `$nu.config-path` variable either shows the default configuration file (or the custom one, if given)
* We can now run end to end tests with finer grained control (currently, since this is baseline work, standard out) This will allow to check things like exit status, assert the contents with a format, etc)
* Remove (for another PR)
* update docs to refer to length instead of count
* rename count to length
* change all occurrences of 'count' to 'length' in tests
* format length command
The autoenv logic mutates environment variables in the running session as
it operates and decides what to do for trusted directories containing `.nu-env`
files. Few of the ways to interact with it were all in a single test function.
We separate out all the ways that were done in the single test function to document
it better. This will greatly help once we start refactoring our way out from setting
environment variables this way to just setting them to `Scope`.
This is part of an on-going effort to keep variables (`PATH` and `ENV`)
in our `Scope` and rely on it for everything related to variables.
We expect to move away from setting (`std::*`) envrironment variables in the current
running process. This is non-trivial since we need to handle cases from vars
coming in from the outside world, prioritize, and also compare to the ones
we have both stored in memory and in configuration files.
Also to send out our in-memory (in `Scope`) variables properly to external
programs once we no longer rely on `std::env` vars from the running process.
* Begin allowing comments and multiline scripts.
* clippy
* Finish moving to groups. Test pass
* Keep going
* WIP
* WIP
* BROKEN WIP
* WIP
* WIP
* Fix more tests
* WIP: alias starts working
* Broken WIP
* Broken WIP
* Variables begin to work
* captures start working
* A little better but needs fixed scope
* Shorthand env setting
* Update main merge
* Broken WIP
* WIP
* custom command parsing
* Custom commands start working
* Fix coloring and parsing of block
* Almost there
* Add some tests
* Add more param types
* Bump version
* Fix benchmark
* Fix stuff
We introduce the `plugin` nu sub command (`nu plugin`) with basic plugin
loading support. We can choose to load plugins from a directory. Originally
introduced to make integration tests faster (by not loading any plugins on startup at all)
but `nu plugin --load some_path ; test_pipeline_that_uses_plugins_just_loaded` does not see it.
Therefore, a `nu_with_plugins!` macro for tests was introduced on top of nu`s `--skip-plugins`
switch executable which is set to true when running the integration tests that use the `nu!` macro now..
* Implement exclusive and inclusive ranges with .. and ..=
This commit adds right-exclusive ranges.
The original a..b inclusive syntax was changed to reflect the Rust notation.
New a..=b syntax was introduced to have the old behavior.
Currently, both a.. and b..= is valid, and it is unclear whether it's valid
to impose restrictions.
The original issue suggests .. for inclusive and ..< for exclusive ranges,
this can be implemented by making simple changes to this commit.
* Fix collect tests by changing ranges to ..=
* Fix clippy lints in exclusive range matching
* Implement exclusive ranges using `..<`
* Modify testcase
* Run exitscript in the folder it was specified
* Update documentation
* Add comment
* Borrow instead of clone
* Does this just... work on windows?
* fmt
* as_str
* Collapse if by order of clippy
* Support windows
* fmt
* refactor tests
* fmt
* This time it will work on windows FOR SURE
* Remove debug prints
* Comment
* Refactor tests
* fmt
* fix spelling
* update comment
* Working towards a PoC for wasm
* Move bson and sqlite to plugins
* proof of concept now working
* tests are green
* Add CI test for --no-default-features
* Fix some tests
* Fix clippy and windows build
* More fixes
* Fix the windows build
* Fix the windows test
* Fix autoenv executing scripts multiple times
Previously, if the user had only specified entry or exitscripts the scripts
would execute many times. This should be fixed now
* Add tests
* Run exitscripts
* More tests and fixes to existing tests
* Test solution with visited dirs
* Track visited directories
* Comments and fmt
* add test basic_autoenv_vars_are_added
* Tests
* Entry and exit scripts
* Recursive set and overwrite
* Make sure that overwritten vals are restored
* Move tests to autoenv
* Move tests out of cli crate
* Tests help, apparently. Windows has issues
On windows, .nu-env is not applied immediately after running autoenv trust.
You have to cd out of the directory for it to work.
* Sort paths non-lexicographically
* Sibling dir test
* Revert "Sort paths non-lexicographically"
This reverts commit 72e4b856af.
* Rename test
* Change conditions
* Revert "Revert "Sort paths non-lexicographically""
This reverts commit 71606bc62f.
* Set vars as they are discovered
This means that if a parent directory is untrusted,
the variables in its child directories are still set properly.
* format
* Fix cleanup issues too
* Run commands in their separate functions
* Make everything into one large function like all the cool kids
* Refactoring
* fmt
* Debugging windows path issue
* Canonicalize
* Trim whitespace
* On windows, use echo nul instead of touch to create file in test
* Avoid cloning by using drain()
Our own custom escaping unfortunately is far too simple to cover all cases.
Instead, the parser will now do no transforms on the args passed to an external
command, letting the process spawning library deal with doing the appropriate
escaping.
For example, when running the following:
crates/nu-cli/src
nushell currently parses this as an external command. Before running the command, we check to see if
it's a directory. If it is, we "auto cd" into that directory, otherwise we go through normal
external processing.
If we put a trailing slash on it though, shells typically interpret that as "user is explicitly
referencing directory". So
crates/nu-cli/src/
should not be interpreted as "run an external command". We intercept a trailing slash in the head
position of a command in a pipeline as such, and inject a `cd` internal command.
* from-eml initial ver
* Adding tests for `from-eml`
* Add eml to prepares_and_decorates_filesystem_source_files
* Sort the file order
Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
* headers plugin
* Remove plugin
* Add non-functioning headers command
* Add ability to extract headers from first row
* Refactor header extraction
* Rebuild indexmap with proper headers
* Rebuild result properly
* Compiling, probably wrapped too much?
* Refactoring
* Deal with case of empty header cell
* Deal with case of empty header cell
* Fix formatting
* Fix linting, attempt 2.
* Move whole_stream_command(Headers) to more appropriate section
* ... more linting
* Return Err(ShellError...) instead of panic, yield each row instead of entire table
* Insert Column[index] if no header info is found.
* Update error description
* Add initial test
* Add tests for headers command
* Lint test cases in headers
* Change ShellError for headers, Add sample_headers file to utils.rs
* Add empty sheet to test file
* Revert "Add empty sheet to test file"
This reverts commit a4bf38a31d.
* Show error message when given empty table
* WIP: move to bytes codec
* Progress on adding collect helpers
* Progress on adding collect helpers
* Add in line splitting back to lines
* Lines outputting line primitives
* Close to ready?
* Finish fixing lines
* clippy fixes
* fmt fixes
* removed unused code
* Cleanup a few bits
* Cleanup a few bits
* Cleanup a few more bits
* Fix failing test with corrected test case
This improves incremental build time when working on what was previously
the root package. For example, previously all plugins would be rebuilt
with a change to `src/commands/classified/external.rs`, but now only
`nu-cli` will have to be rebuilt (and anything that depends on it).
In particular, one thing that we can't (properly) do before this commit
is consuming an infinite input stream. For example:
```
yes | grep y | head -n10
```
will give 10 "y"s in most shells, but blocks indefinitely in nu. This PR
resolves that by doing blocking I/O in threads, and reducing the `await`
calls we currently have in our pipeline code.
* typo fixes
* Change signature to take in short-hand flags
* update help information
* Parse short-hand flags as their long counterparts
* lints
* Modified a couple tests to use shorthand flags
* Fixed mv not throwing error when the source path was invalid
* Fixed failing test
* Fixed another lint error
* Fix $PATH conflicts in .gitpod.Dockerfile (#1349)
- Use the correct user for gitpod Dockerfile.
- Remove unneeded packages (curl, rustc) from gitpod Dockerfile.
* Added test to check for the error
* Fixed linting error
* Fixed mv not moving files on Windows. (#1342)
Move files correctly in windows.
* Fixed mv not throwing error when the source path was invalid
* Fixed failing test
* Fixed another lint error
* Added test to check for the error
* Fixed linting error
* Changed error message
* Typo and fixed test
Co-authored-by: Sean Hellum <seanhellum45@gmail.com>
* Added attributes to from-xml command
* Added attributes as their own rows
* Removed unneccesary lifetime declarations
* from-xml now has children and attributes side by side
* Fixed tests and linting
* Fixed lint-problem
* Switch to using `shell`
Switch to using the shell for subprocess to enable more natural shelling out.
* Update external.rs
* This is a test with .shell() for external
* El pollo loco's PR
* co co co
* Attempt to fix windows
* Fmt
* Less is more?
Co-authored-by: Andrés N. Robalino <andres@androbtech.com>
Restructure and streamline token expansion
The purpose of this commit is to streamline the token expansion code, by
removing aspects of the code that are no longer relevant, removing
pointless duplication, and eliminating the need to pass the same
arguments to `expand_syntax`.
The first big-picture change in this commit is that instead of a handful
of `expand_` functions, which take a TokensIterator and ExpandContext, a
smaller number of methods on the `TokensIterator` do the same job.
The second big-picture change in this commit is fully eliminating the
coloring traits, making coloring a responsibility of the base expansion
implementations. This also means that the coloring tracer is merged into
the expansion tracer, so you can follow a single expansion and see how
the expansion process produced colored tokens.
One side effect of this change is that the expander itself is marginally
more error-correcting. The error correction works by switching from
structured expansion to `BackoffColoringMode` when an unexpected token
is found, which guarantees that all spans of the source are colored, but
may not be the most optimal error recovery strategy.
That said, because `BackoffColoringMode` only extends as far as a
closing delimiter (`)`, `]`, `}`) or pipe (`|`), it does result in
fairly granular correction strategy.
The current code still produces an `Err` (plus a complete list of
colored shapes) from the parsing process if any errors are encountered,
but this could easily be addressed now that the underlying expansion is
error-correcting.
This commit also colors any spans that are syntax errors in red, and
causes the parser to include some additional information about what
tokens were expected at any given point where an error was encountered,
so that completions and hinting could be more robust in the future.
Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
Co-authored-by: Andrés N. Robalino <andres@androbtech.com>
Also, this commit makes `ls` a per-item command.
A command that processes things item by item may still take some time to stream
out the results from a single item. For example, `ls` on a directory with a lot
of files could be interrupted in the middle of showing all of these files.
This commit changes the way we shell out externals when using the `"$it"` argument. Also pipes per row to an external's stdin if no `"$it"` argument is present for external commands.
Further separation of logic (preparing the external's command arguments, getting the data for piping, emitting values, spawning processes) will give us a better idea for lower level details regarding external commands until we can find the right abstractions for making them more generic and unify within the pipeline calling logic of Nu internal's and external's.
* Put a sample_data.ods file for testing
This is a copy of the sample_data.xlsx file but in ods format
* Add the from-ods command
Most of the work was doing `rg xlsx` and then copy/paste with light editing
* Add tests for the from-ods command
* Fix failing test
The problem was improper filename sorting in the test `prepares_and_decorates_filesystem_source_files`
* Clippy fixes
* Finish converting to use clippy
* fix warnings in new master
* fix windows
* fix windows
Co-authored-by: Artem Vorotnikov <artem@vorotnikov.me>
* start playing with ways to use the uniq command
* WIP
* Got uniq working, but still need to figure out args issue and add tests
* Add some tests for uniq
* fmt
* remove commented out code
* Add documentation and some additional tests showing uniq values and rows. Also removed args TODO
* add changes that didn't get committed
* whoops, I didn't save the docs correctly...
* fmt
* Add a test for uniq with nested json
* Add another test
* Fix unique-ness when json keys are out of order and make the test json more complicated
Add tests for ~tilde expansion:
- test that "~" is expanded (no more "~" in output)
- ensure that "1~1" is not expanded to "1/home/user1" as it was
before
Fixes#972
Note: the first test does not check the literal expansion because
the path on Windows is expanded as a Linux path, but the correct
expansion may come for free once `shellexpand` will use the `dirs`
crate too (https://github.com/netvl/shellexpand/issues/3).
This commit contains two improvements:
- Support for a Range syntax (and a corresponding Range value)
- Work towards a signature syntax
Implementing the Range syntax resulted in cleaning up how operators in
the core syntax works. There are now two kinds of infix operators
- tight operators (`.` and `..`)
- loose operators
Tight operators may not be interspersed (`$it.left..$it.right` is a
syntax error). Loose operators require whitespace on both sides of the
operator, and can be arbitrarily interspersed. Precedence is left to
right in the core syntax.
Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single
token node in the core syntax. A single token node can be parsed from
beginning to end in a context-free manner.
The rule for `.` is `<token node>.<member>`. The rule for `..` is
`<token node>..<token node>`.
Loose operators all have the same syntactic rule: `<token
node><space><loose op><space><token node>`.
The second aspect of this pull request is the beginning of support for a
signature syntax. Before implementing signatures, a necessary
prerequisite is for the core syntax to support multi-line programs.
That work establishes a few things:
- `;` and newlines are handled in the core grammar, and both count as
"separators"
- line comments begin with `#` and continue until the end of the line
In this commit, multi-token productions in the core grammar can use
separators interchangably with spaces. However, I think we will
ultimately want a different rule preventing separators from occurring
before an infix operator, so that the end of a line is always
unambiguous. This would avoid gratuitous differences between modules and
repl usage.
We already effectively have this rule, because otherwise `x<newline> |
y` would be a single pipeline, but of course that wouldn't work.
`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.
After the previous commit, nushell uses PrettyDebug and
PrettyDebugWithSource for our pretty-printed display output.
PrettyDebug produces a structured `pretty.rs` document rather than
writing directly into a fmt::Formatter, and types that implement
`PrettyDebug` have a convenience `display` method that produces a string
(to be used in situations where `Display` is needed for compatibility
with other traits, or where simple rendering is appropriate).
fixes#969, admittedly without a --delimiter alias
moves from_structured_data.rs to from_delimited_data.rs to better
identify its scope and adds to_delimited_data.rs. Now csv and tsv both
use the same code, tsv passes in a fixed '\t' argument where csv passes
in the value of --separator
With the proposed changes, these tests now become invalid. If the first line is
to be counted as data, then converting the headers to ints will fail. Removing
the headers and instead treating the first line as data, however, reflects the
new, desired mode of operation.
tables and able to work with them for data processing & viewing
purposes. At the moment, certain ways to process said tables we
are able to view a histogram of a given column.
As usage matures, we may find certain core commands that could
be used ergonomically when working with tables on Nu.
a joy. Fundamentally we embrace functional programming principles for
transforming the dataset from any format picked up by Nu. This table
processing "primitive" commands will build up and make pipelines
composable with data processing capabilities allowing us the valuate,
reduce, and map, the tables as far as even composing this declartively.
On this regard, `split-by` expects some table with grouped data and we
can use it further in interesting ways (Eg. collecting labels for
visualizing the data in charts and/or suit it for a particular chart
of our interest).
This commit should finish the `coloring_in_tokens` feature, which moves
the shape accumulator into the token stream. This allows rollbacks of
the token stream to also roll back any shapes that were added.
This commit also adds a much nicer syntax highlighter trace, which shows
all of the paths the highlighter took to arrive at a particular coloring
output. This change is fairly substantial, but really improves the
understandability of the flow. I intend to update the normal parser with
a similar tracing view.
In general, this change also fleshes out the concept of "atomic" token
stream operations.
A good next step would be to try to make the parser more
error-correcting, using the coloring infrastructure. A follow-up step
would involve merging the parser and highlighter shapes themselves.
Previously, we would build a command that looked something like this:
<ex_cmd> "$it" "&&" "<ex_cmd>" "$it"
So that the "&&" and "<ex_cmd>" would also be arguments to the command,
instead of a chained command. This commit builds up a command string
that can be passed to an external shell.
* Moves off of draining between filters. Instead, the sink will pull on the stream, and will drain element-wise. This moves the whole stream to being lazy.
* Adds ctrl-c support and connects it into some of the key points where we pull on the stream. If a ctrl-c is detect, we immediately halt pulling on the stream and return to the prompt.
* Moves away from having a SourceMap where anchor locations are stored. Now AnchorLocation is kept directly in the Tag.
* To make this possible, split tag and span. Span is largely used in the parser and is copyable. Tag is now no longer copyable.
The main thrust of this (very large) commit is an overhaul of the
expansion system.
The parsing pipeline is:
- Lightly parse the source file for atoms, basic delimiters and pipeline
structure into a token tree
- Expand the token tree into a HIR (high-level intermediate
representation) based upon the baseline syntax rules for expressions
and the syntactic shape of commands.
Somewhat non-traditionally, nu doesn't have an AST at all. It goes
directly from the token tree, which doesn't represent many important
distinctions (like the difference between `hello` and `5KB`) directly
into a high-level representation that doesn't have a direct
correspondence to the source code.
At a high level, nu commands work like macros, in the sense that the
syntactic shape of the invocation of a command depends on the
definition of a command.
However, commands do not have the ability to perform unrestricted
expansions of the token tree. Instead, they describe their arguments in
terms of syntactic shapes, and the expander expands the token tree into
HIR based upon that definition.
For example, the `where` command says that it takes a block as its first
required argument, and the description of the block syntactic shape
expands the syntax `cpu > 10` into HIR that represents
`{ $it.cpu > 10 }`.
This commit overhauls that system so that the syntactic shapes are
described in terms of a few new traits (`ExpandSyntax` and
`ExpandExpression` are the primary ones) that are more composable than
the previous system.
The first big win of this new system is the addition of the `ColumnPath`
shape, which looks like `cpu."max ghz"` or `package.version`.
Previously, while a variable path could look like `$it.cpu."max ghz"`,
the tail of a variable path could not be easily reused in other
contexts. Now, that tail is its own syntactic shape, and it can be used
as part of a command's signature.
This cleans up commands like `inc`, `add` and `edit` as well as
shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
with the `help` command to explore and list all commands available.
Enter will also try to see if the location to be entered is an existing
Nu command, if it is it will let you inspect the command under `help`.
This provides baseline needed so we can iterate on it.
