nushell/src/commands/classified/internal.rs
Yehuda Katz 7efb31a4e4 Restructure and streamline token expansion (#1123)
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>
2020-01-21 17:45:03 -05:00

171 lines
7.2 KiB
Rust

use crate::commands::UnevaluatedCallInfo;
use crate::prelude::*;
use log::{log_enabled, trace};
use nu_errors::ShellError;
use nu_parser::InternalCommand;
use nu_protocol::{CommandAction, Primitive, ReturnSuccess, UntaggedValue, Value};
pub(crate) async fn run_internal_command(
command: InternalCommand,
context: &mut Context,
input: Option<InputStream>,
source: Text,
) -> Result<Option<InputStream>, ShellError> {
if log_enabled!(log::Level::Trace) {
trace!(target: "nu::run::internal", "->");
trace!(target: "nu::run::internal", "{}", command.name);
trace!(target: "nu::run::internal", "{}", command.args.debug(&source));
}
let objects: InputStream = if let Some(input) = input {
trace_stream!(target: "nu::trace_stream::internal", "input" = input)
} else {
InputStream::empty()
};
let internal_command = context.expect_command(&command.name);
let result = {
context.run_command(
internal_command?,
command.name_tag.clone(),
command.args.clone(),
&source,
objects,
)
};
let result = trace_out_stream!(target: "nu::trace_stream::internal", "output" = result);
let mut result = result.values;
let mut context = context.clone();
let stream = async_stream! {
let mut soft_errs: Vec<ShellError> = vec![];
let mut yielded = false;
while let Some(item) = result.next().await {
match item {
Ok(ReturnSuccess::Action(action)) => match action {
CommandAction::ChangePath(path) => {
context.shell_manager.set_path(path);
}
CommandAction::Exit => std::process::exit(0), // TODO: save history.txt
CommandAction::Error(err) => {
context.error(err);
break;
}
CommandAction::AutoConvert(tagged_contents, extension) => {
let contents_tag = tagged_contents.tag.clone();
let command_name = format!("from-{}", extension);
let command = command.clone();
if let Some(converter) = context.registry.get_command(&command_name) {
let new_args = RawCommandArgs {
host: context.host.clone(),
ctrl_c: context.ctrl_c.clone(),
shell_manager: context.shell_manager.clone(),
call_info: UnevaluatedCallInfo {
args: nu_parser::hir::Call {
head: command.args.head,
positional: None,
named: None,
span: Span::unknown()
},
source: source.clone(),
name_tag: command.name_tag,
}
};
let mut result = converter.run(new_args.with_input(vec![tagged_contents]), &context.registry);
let result_vec: Vec<Result<ReturnSuccess, ShellError>> = result.drain_vec().await;
for res in result_vec {
match res {
Ok(ReturnSuccess::Value(Value { value: UntaggedValue::Table(list), ..})) => {
for l in list {
yield Ok(l);
}
}
Ok(ReturnSuccess::Value(Value { value, .. })) => {
yield Ok(value.into_value(contents_tag.clone()));
}
Err(e) => yield Err(e),
_ => {}
}
}
} else {
yield Ok(tagged_contents)
}
}
CommandAction::EnterHelpShell(value) => {
match value {
Value {
value: UntaggedValue::Primitive(Primitive::String(cmd)),
tag,
} => {
context.shell_manager.insert_at_current(Box::new(
HelpShell::for_command(
UntaggedValue::string(cmd).into_value(tag),
&context.registry(),
)?,
));
}
_ => {
context.shell_manager.insert_at_current(Box::new(
HelpShell::index(&context.registry())?,
));
}
}
}
CommandAction::EnterValueShell(value) => {
context
.shell_manager
.insert_at_current(Box::new(ValueShell::new(value)));
}
CommandAction::EnterShell(location) => {
context.shell_manager.insert_at_current(Box::new(
FilesystemShell::with_location(location, context.registry().clone()),
));
}
CommandAction::PreviousShell => {
context.shell_manager.prev();
}
CommandAction::NextShell => {
context.shell_manager.next();
}
CommandAction::LeaveShell => {
context.shell_manager.remove_at_current();
if context.shell_manager.is_empty() {
std::process::exit(0); // TODO: save history.txt
}
}
},
Ok(ReturnSuccess::Value(v)) => {
yielded = true;
yield Ok(v);
}
Ok(ReturnSuccess::DebugValue(v)) => {
yielded = true;
let doc = PrettyDebug::pretty_doc(&v);
let mut buffer = termcolor::Buffer::ansi();
let _ = doc.render_raw(
context.with_host(|host| host.width() - 5),
&mut nu_source::TermColored::new(&mut buffer),
);
let value = String::from_utf8_lossy(buffer.as_slice());
yield Ok(UntaggedValue::string(value).into_untagged_value())
}
Err(err) => {
context.error(err);
break;
}
}
}
};
Ok(Some(stream.to_input_stream()))
}