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eval.rs
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eval.rs
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use crate::{current_dir_str, get_config, get_full_help};
use nu_path::expand_path_with;
use nu_protocol::{
ast::{
Argument, Assignment, Block, Call, Expr, Expression, ExternalArgument, PathMember,
PipelineElement, Redirection,
},
engine::{Closure, EngineState, Stack},
eval_base::Eval,
Config, DeclId, IntoPipelineData, PipelineData, RawStream, ShellError, Span, Spanned, Type,
Value, VarId, ENV_VARIABLE_ID,
};
use std::thread::{self, JoinHandle};
use std::{borrow::Cow, collections::HashMap};
pub fn eval_call(
engine_state: &EngineState,
caller_stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
return Ok(Value::nothing(call.head).into_pipeline_data());
}
let decl = engine_state.get_decl(call.decl_id);
if !decl.is_known_external() && call.named_iter().any(|(flag, _, _)| flag.item == "help") {
let mut signature = engine_state.get_signature(decl);
signature.usage = decl.usage().to_string();
signature.extra_usage = decl.extra_usage().to_string();
let full_help = get_full_help(
&signature,
&decl.examples(),
engine_state,
caller_stack,
decl.is_parser_keyword(),
);
Ok(Value::string(full_help, call.head).into_pipeline_data())
} else if let Some(block_id) = decl.get_block_id() {
let block = engine_state.get_block(block_id);
let mut callee_stack = caller_stack.gather_captures(engine_state, &block.captures);
// Rust does not check recursion limits outside of const evaluation.
// But nu programs run in the same process as the shell.
// To prevent a stack overflow in user code from crashing the shell,
// we limit the recursion depth of function calls.
// Picked 50 arbitrarily, should work on all architectures.
const MAXIMUM_CALL_STACK_DEPTH: u64 = 50;
callee_stack.recursion_count += 1;
if callee_stack.recursion_count > MAXIMUM_CALL_STACK_DEPTH {
callee_stack.recursion_count = 0;
return Err(ShellError::RecursionLimitReached {
recursion_limit: MAXIMUM_CALL_STACK_DEPTH,
span: block.span,
});
}
for (param_idx, (param, required)) in decl
.signature()
.required_positional
.iter()
.map(|p| (p, true))
.chain(
decl.signature()
.optional_positional
.iter()
.map(|p| (p, false)),
)
.enumerate()
{
let var_id = param
.var_id
.expect("internal error: all custom parameters must have var_ids");
if let Some(arg) = call.positional_nth(param_idx) {
let result = eval_expression(engine_state, caller_stack, arg)?;
let param_type = param.shape.to_type();
if required && !result.get_type().is_subtype(¶m_type) {
// need to check if result is an empty list, and param_type is table or list
// nushell needs to pass type checking for the case.
let empty_list_matches = result
.as_list()
.map(|l| {
l.is_empty() && matches!(param_type, Type::List(_) | Type::Table(_))
})
.unwrap_or(false);
if !empty_list_matches {
return Err(ShellError::CantConvert {
to_type: param.shape.to_type().to_string(),
from_type: result.get_type().to_string(),
span: result.span(),
help: None,
});
}
}
callee_stack.add_var(var_id, result);
} else if let Some(value) = ¶m.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::nothing(call.head));
}
}
if let Some(rest_positional) = decl.signature().rest_positional {
let mut rest_items = vec![];
for result in call.rest_iter_flattened(
decl.signature().required_positional.len()
+ decl.signature().optional_positional.len(),
|expr| eval_expression(engine_state, caller_stack, expr),
)? {
rest_items.push(result);
}
let span = if let Some(rest_item) = rest_items.first() {
rest_item.span()
} else {
call.head
};
callee_stack.add_var(
rest_positional
.var_id
.expect("Internal error: rest positional parameter lacks var_id"),
Value::list(rest_items, span),
)
}
for named in decl.signature().named {
if let Some(var_id) = named.var_id {
let mut found = false;
for call_named in call.named_iter() {
if let (Some(spanned), Some(short)) = (&call_named.1, named.short) {
if spanned.item == short.to_string() {
if let Some(arg) = &call_named.2 {
let result = eval_expression(engine_state, caller_stack, arg)?;
callee_stack.add_var(var_id, result);
} else if let Some(value) = &named.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::bool(true, call.head))
}
found = true;
}
} else if call_named.0.item == named.long {
if let Some(arg) = &call_named.2 {
let result = eval_expression(engine_state, caller_stack, arg)?;
callee_stack.add_var(var_id, result);
} else if let Some(value) = &named.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::bool(true, call.head))
}
found = true;
}
}
if !found {
if named.arg.is_none() {
callee_stack.add_var(var_id, Value::bool(false, call.head))
} else if let Some(value) = named.default_value {
callee_stack.add_var(var_id, value);
} else {
callee_stack.add_var(var_id, Value::nothing(call.head))
}
}
}
}
let result = eval_block_with_early_return(
engine_state,
&mut callee_stack,
block,
input,
call.redirect_stdout,
call.redirect_stderr,
);
if block.redirect_env {
redirect_env(engine_state, caller_stack, &callee_stack);
}
result
} else {
// We pass caller_stack here with the knowledge that internal commands
// are going to be specifically looking for global state in the stack
// rather than any local state.
decl.run(engine_state, caller_stack, call, input)
}
}
/// Redirect the environment from callee to the caller.
pub fn redirect_env(engine_state: &EngineState, caller_stack: &mut Stack, callee_stack: &Stack) {
// Grab all environment variables from the callee
let caller_env_vars = caller_stack.get_env_var_names(engine_state);
// remove env vars that are present in the caller but not in the callee
// (the callee hid them)
for var in caller_env_vars.iter() {
if !callee_stack.has_env_var(engine_state, var) {
caller_stack.remove_env_var(engine_state, var);
}
}
// add new env vars from callee to caller
for (var, value) in callee_stack.get_stack_env_vars() {
caller_stack.add_env_var(var, value);
}
}
enum RedirectTarget {
Piped(bool, bool),
CombinedPipe,
}
#[allow(clippy::too_many_arguments)]
fn eval_external(
engine_state: &EngineState,
stack: &mut Stack,
head: &Expression,
args: &[ExternalArgument],
input: PipelineData,
redirect_target: RedirectTarget,
is_subexpression: bool,
) -> Result<PipelineData, ShellError> {
let decl_id = engine_state
.find_decl("run-external".as_bytes(), &[])
.ok_or(ShellError::ExternalNotSupported { span: head.span })?;
let command = engine_state.get_decl(decl_id);
let mut call = Call::new(head.span);
call.add_positional(head.clone());
for arg in args {
match arg {
ExternalArgument::Regular(expr) => call.add_positional(expr.clone()),
ExternalArgument::Spread(expr) => call.add_spread(expr.clone()),
}
}
match redirect_target {
RedirectTarget::Piped(redirect_stdout, redirect_stderr) => {
if redirect_stdout {
call.add_named((
Spanned {
item: "redirect-stdout".into(),
span: head.span,
},
None,
None,
))
}
if redirect_stderr {
call.add_named((
Spanned {
item: "redirect-stderr".into(),
span: head.span,
},
None,
None,
))
}
}
RedirectTarget::CombinedPipe => call.add_named((
Spanned {
item: "redirect-combine".into(),
span: head.span,
},
None,
None,
)),
}
if is_subexpression {
call.add_named((
Spanned {
item: "trim-end-newline".into(),
span: head.span,
},
None,
None,
))
}
command.run(engine_state, stack, &call, input)
}
pub fn eval_expression(
engine_state: &EngineState,
stack: &mut Stack,
expr: &Expression,
) -> Result<Value, ShellError> {
<EvalRuntime as Eval>::eval(engine_state, stack, expr)
}
/// Checks the expression to see if it's a internal or external call. If so, passes the input
/// into the call and gets out the result
/// Otherwise, invokes the expression
///
/// It returns PipelineData with a boolean flag, indicating if the external failed to run.
/// The boolean flag **may only be true** for external calls, for internal calls, it always to be false.
pub fn eval_expression_with_input(
engine_state: &EngineState,
stack: &mut Stack,
expr: &Expression,
mut input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
) -> Result<(PipelineData, bool), ShellError> {
match expr {
Expression {
expr: Expr::Call(call),
..
} => {
if !redirect_stdout || redirect_stderr {
// we're doing something different than the defaults
let mut call = call.clone();
call.redirect_stdout = redirect_stdout;
call.redirect_stderr = redirect_stderr;
input = eval_call(engine_state, stack, &call, input)?;
} else {
input = eval_call(engine_state, stack, call, input)?;
}
}
Expression {
expr: Expr::ExternalCall(head, args, is_subexpression),
..
} => {
input = eval_external(
engine_state,
stack,
head,
args,
input,
RedirectTarget::Piped(redirect_stdout, redirect_stderr),
*is_subexpression,
)?;
}
Expression {
expr: Expr::Subexpression(block_id),
..
} => {
let block = engine_state.get_block(*block_id);
// FIXME: protect this collect with ctrl-c
input = eval_subexpression(engine_state, stack, block, input)?;
}
elem @ Expression {
expr: Expr::FullCellPath(full_cell_path),
..
} => match &full_cell_path.head {
Expression {
expr: Expr::Subexpression(block_id),
span,
..
} => {
let block = engine_state.get_block(*block_id);
// FIXME: protect this collect with ctrl-c
input = eval_subexpression(engine_state, stack, block, input)?;
let value = input.into_value(*span);
input = value
.follow_cell_path(&full_cell_path.tail, false)?
.into_pipeline_data()
}
_ => {
input = eval_expression(engine_state, stack, elem)?.into_pipeline_data();
}
},
elem => {
input = eval_expression(engine_state, stack, elem)?.into_pipeline_data();
}
};
// Given input is PipelineData::ExternalStream
// `might_consume_external_result` will consume `stderr` stream if `stdout` is empty.
// it's not intended if user want to redirect stderr message.
//
// e.g:
// 1. cargo check e>| less
// 2. cargo check e> result.txt
//
// In these two cases, stdout will be empty, but nushell shouldn't consume the `stderr`
// stream it needs be passed to next command.
if !redirect_stderr {
Ok(might_consume_external_result(input))
} else {
Ok((input, false))
}
}
// Try to catch and detect if external command runs to failed.
fn might_consume_external_result(input: PipelineData) -> (PipelineData, bool) {
input.is_external_failed()
}
#[allow(clippy::too_many_arguments)]
fn eval_element_with_input(
engine_state: &EngineState,
stack: &mut Stack,
element: &PipelineElement,
mut input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
redirect_combine: bool,
stderr_writer_jobs: &mut Vec<DataSaveJob>,
) -> Result<(PipelineData, bool), ShellError> {
match element {
PipelineElement::Expression(pipe_span, expr)
| PipelineElement::OutErrPipedExpression(pipe_span, expr) => {
if matches!(element, PipelineElement::OutErrPipedExpression(..))
&& !matches!(input, PipelineData::ExternalStream { .. })
{
return Err(ShellError::GenericError {
error: "`o+e>|` only works with external streams".into(),
msg: "`o+e>|` only works on external streams".into(),
span: *pipe_span,
help: None,
inner: vec![],
});
}
match expr {
Expression {
expr: Expr::ExternalCall(head, args, is_subexpression),
..
} if redirect_combine => {
let result = eval_external(
engine_state,
stack,
head,
args,
input,
RedirectTarget::CombinedPipe,
*is_subexpression,
)?;
Ok(might_consume_external_result(result))
}
_ => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
}
}
PipelineElement::ErrPipedExpression(pipe_span, expr) => {
let input = match input {
PipelineData::ExternalStream {
stdout,
stderr,
exit_code,
span,
metadata,
trim_end_newline,
} => PipelineData::ExternalStream {
stdout: stderr, // swap stderr and stdout to get stderr piped feature.
stderr: stdout,
exit_code,
span,
metadata,
trim_end_newline,
},
_ => {
return Err(ShellError::GenericError {
error: "`e>|` only works with external streams".into(),
msg: "`e>|` only works on external streams".into(),
span: *pipe_span,
help: None,
inner: vec![],
})
}
};
eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
)
}
PipelineElement::Redirection(span, redirection, expr, is_append_mode) => {
match &expr.expr {
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_, _) => {
let exit_code = match &mut input {
PipelineData::ExternalStream { exit_code, .. } => exit_code.take(),
_ => None,
};
let (input, result_out_stream, result_is_out) =
adjust_stream_for_input_and_output(input, redirection);
if let Some(save_command) = engine_state.find_decl(b"save", &[]) {
let save_call = gen_save_call(
save_command,
(*span, expr.clone(), *is_append_mode),
None,
);
match result_out_stream {
None => {
eval_call(engine_state, stack, &save_call, input).map(|_| {
// save is internal command, normally it exists with non-ExternalStream
// but here in redirection context, we make it returns ExternalStream
// So nu handles exit_code correctly
//
// Also, we don't want to run remaining commands if this command exits with non-zero
// exit code, so we need to consume and check exit_code too
might_consume_external_result(PipelineData::ExternalStream {
stdout: None,
stderr: None,
exit_code,
span: *span,
metadata: None,
trim_end_newline: false,
})
})
}
Some(result_out_stream) => {
// delegate to a different thread
// so nushell won't hang if external command generates both too much
// stderr and stdout message
let stderr_stack = stack.clone();
let engine_state_clone = engine_state.clone();
stderr_writer_jobs.push(DataSaveJob::spawn(
engine_state_clone,
stderr_stack,
save_call,
input,
));
let (result_out_stream, result_err_stream) = if result_is_out {
(result_out_stream, None)
} else {
// we need `stdout` to be an empty RawStream
// so nushell knows this result is not the last part of a command.
(
Some(RawStream::new(
Box::new(vec![].into_iter()),
None,
*span,
Some(0),
)),
result_out_stream,
)
};
Ok(might_consume_external_result(
PipelineData::ExternalStream {
stdout: result_out_stream,
stderr: result_err_stream,
exit_code,
span: *span,
metadata: None,
trim_end_newline: false,
},
))
}
}
} else {
Err(ShellError::CommandNotFound { span: *span })
}
}
_ => Err(ShellError::CommandNotFound { span: *span }),
}
}
PipelineElement::SeparateRedirection {
out: (out_span, out_expr, out_append_mode),
err: (err_span, err_expr, err_append_mode),
} => match (&out_expr.expr, &err_expr.expr) {
(
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_, _),
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_, _),
) => {
if let Some(save_command) = engine_state.find_decl(b"save", &[]) {
let exit_code = match &mut input {
PipelineData::ExternalStream { exit_code, .. } => exit_code.take(),
_ => None,
};
let save_call = gen_save_call(
save_command,
(*out_span, out_expr.clone(), *out_append_mode),
Some((*err_span, err_expr.clone(), *err_append_mode)),
);
eval_call(engine_state, stack, &save_call, input).map(|_| {
// save is internal command, normally it exists with non-ExternalStream
// but here in redirection context, we make it returns ExternalStream
// So nu handles exit_code correctly
might_consume_external_result(PipelineData::ExternalStream {
stdout: None,
stderr: None,
exit_code,
span: *out_span,
metadata: None,
trim_end_newline: false,
})
})
} else {
Err(ShellError::CommandNotFound { span: *out_span })
}
}
(_out_other, err_other) => {
if let Expr::String(_) = err_other {
Err(ShellError::CommandNotFound { span: *out_span })
} else {
Err(ShellError::CommandNotFound { span: *err_span })
}
}
},
PipelineElement::SameTargetRedirection {
cmd: (cmd_span, cmd_exp),
redirection: (redirect_span, redirect_exp, is_append_mode),
} => {
// general idea: eval cmd and call save command to redirect stdout to result.
input = match &cmd_exp.expr {
Expr::ExternalCall(head, args, is_subexpression) => {
// if cmd's expression is ExternalStream, then invoke run-external with
// special --redirect-combine flag.
eval_external(
engine_state,
stack,
head,
args,
input,
RedirectTarget::CombinedPipe,
*is_subexpression,
)?
}
_ => {
// we need to redirect output, so the result can be saved and pass to `save` command.
eval_element_with_input(
engine_state,
stack,
&PipelineElement::Expression(*cmd_span, cmd_exp.clone()),
input,
true,
redirect_stderr,
redirect_combine,
stderr_writer_jobs,
)
.map(|x| x.0)?
}
};
eval_element_with_input(
engine_state,
stack,
&PipelineElement::Redirection(
*redirect_span,
Redirection::Stdout,
redirect_exp.clone(),
*is_append_mode,
),
input,
redirect_stdout,
redirect_stderr,
redirect_combine,
stderr_writer_jobs,
)
}
PipelineElement::And(_, expr) => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
PipelineElement::Or(_, expr) => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
}
}
// In redirection context, if nushell gets an ExternalStream
// it might want to take a stream from `input`(if `input` is `PipelineData::ExternalStream`)
// so this stream can be handled by next command.
//
//
// 1. get a stderr redirection, we need to take `stdout` out of `input`.
// e.g: nu --testbin echo_env FOO e> /dev/null | str length
// 2. get a stdout redirection, we need to take `stderr` out of `input`.
// e.g: nu --testbin echo_env FOO o> /dev/null e>| str length
//
// Returns 3 values:
// 1. adjusted pipeline data
// 2. a result stream which is taken from `input`, it can be handled in next command
// 3. a boolean value indicates if result stream should be a stdout stream.
fn adjust_stream_for_input_and_output(
input: PipelineData,
redirection: &Redirection,
) -> (PipelineData, Option<Option<RawStream>>, bool) {
match (redirection, input) {
(
Redirection::Stderr,
PipelineData::ExternalStream {
stdout,
stderr,
exit_code,
span,
metadata,
trim_end_newline,
},
) => (
PipelineData::ExternalStream {
stdout: stderr,
stderr: None,
exit_code,
span,
metadata,
trim_end_newline,
},
Some(stdout),
true,
),
(
Redirection::Stdout,
PipelineData::ExternalStream {
stdout,
stderr,
exit_code,
span,
metadata,
trim_end_newline,
},
) => (
PipelineData::ExternalStream {
stdout,
stderr: None,
exit_code,
span,
metadata,
trim_end_newline,
},
Some(stderr),
false,
),
(_, input) => (input, None, true),
}
}
fn is_redirect_stderr_required(elements: &[PipelineElement], idx: usize) -> bool {
let elements_length = elements.len();
if idx < elements_length - 1 {
let next_element = &elements[idx + 1];
match next_element {
PipelineElement::Redirection(_, Redirection::Stderr, _, _)
| PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _, _)
| PipelineElement::SeparateRedirection { .. }
| PipelineElement::ErrPipedExpression(..)
| PipelineElement::OutErrPipedExpression(..) => return true,
PipelineElement::Redirection(_, Redirection::Stdout, _, _) => {
// a stderr redirection, but we still need to check for the next 2nd
// element, to handle for the following case:
// cat a.txt out> /dev/null e>| lines
//
// we only need to check the next 2nd element because we already make sure
// that we don't have duplicate err> like this:
// cat a.txt out> /dev/null err> /tmp/a
if idx < elements_length - 2 {
let next_2nd_element = &elements[idx + 2];
if matches!(next_2nd_element, PipelineElement::ErrPipedExpression(..)) {
return true;
}
}
}
_ => {}
}
}
false
}
fn is_redirect_stdout_required(elements: &[PipelineElement], idx: usize) -> bool {
let elements_length = elements.len();
if idx < elements_length - 1 {
let next_element = &elements[idx + 1];
match next_element {
// is next element a stdout relative redirection?
PipelineElement::Redirection(_, Redirection::Stdout, _, _)
| PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _, _)
| PipelineElement::SeparateRedirection { .. }
| PipelineElement::Expression(..)
| PipelineElement::OutErrPipedExpression(..) => return true,
PipelineElement::Redirection(_, Redirection::Stderr, _, _) => {
// a stderr redirection, but we still need to check for the next 2nd
// element, to handle for the following case:
// cat a.txt err> /dev/null | lines
//
// we only need to check the next 2nd element because we already make sure
// that we don't have duplicate err> like this:
// cat a.txt err> /dev/null err> /tmp/a
if idx < elements_length - 2 {
let next_2nd_element = &elements[idx + 2];
if matches!(next_2nd_element, PipelineElement::Expression(..)) {
return true;
}
}
}
_ => {}
}
}
false
}
fn is_redirect_combine_required(elements: &[PipelineElement], idx: usize) -> bool {
let elements_length = elements.len();
idx < elements_length - 1
&& matches!(
&elements[idx + 1],
PipelineElement::OutErrPipedExpression(..)
)
}
pub fn eval_block_with_early_return(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
) -> Result<PipelineData, ShellError> {
match eval_block(
engine_state,
stack,
block,
input,
redirect_stdout,
redirect_stderr,
) {
Err(ShellError::Return { span: _, value }) => Ok(PipelineData::Value(*value, None)),
x => x,
}
}
pub fn eval_block(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
mut input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
) -> Result<PipelineData, ShellError> {
let num_pipelines = block.len();
for (pipeline_idx, pipeline) in block.pipelines.iter().enumerate() {
let mut stderr_writer_jobs = vec![];
let elements = &pipeline.elements;
let elements_length = pipeline.elements.len();
for (idx, element) in elements.iter().enumerate() {
let mut redirect_stdout = redirect_stdout;
let mut redirect_stderr = redirect_stderr;
if !redirect_stderr && is_redirect_stderr_required(elements, idx) {
redirect_stderr = true;
}
if !redirect_stdout {
if is_redirect_stdout_required(elements, idx) {
redirect_stdout = true;
}
} else if idx < elements_length - 1
&& matches!(elements[idx + 1], PipelineElement::ErrPipedExpression(..))
{
redirect_stdout = false;
}
let redirect_combine = is_redirect_combine_required(elements, idx);
// if eval internal command failed, it can just make early return with `Err(ShellError)`.
let eval_result = eval_element_with_input(
engine_state,
stack,
element,
input,
redirect_stdout,
redirect_stderr,
redirect_combine,
&mut stderr_writer_jobs,
);
match (eval_result, redirect_stderr) {
(Err(error), true) => {
input = PipelineData::Value(
Value::error(
error,
Span::unknown(), // FIXME: where does this span come from?
),
None,
)
}
(output, _) => {
let output = output?;
input = output.0;
// external command may runs to failed
// make early return so remaining commands will not be executed.
// don't return `Err(ShellError)`, so nushell wouldn't show extra error message.
if output.1 {
return Ok(input);
}
}
}
}
// `eval_element_with_input` may creates some threads
// to write stderr message to a file, here we need to wait and make sure that it's
// finished.
for h in stderr_writer_jobs {
let _ = h.join();
}
if pipeline_idx < (num_pipelines) - 1 {
match input {
PipelineData::Value(Value::Nothing { .. }, ..) => {}
PipelineData::ExternalStream {
ref mut exit_code, ..
} => {
let exit_code = exit_code.take();
input.drain()?;
if let Some(exit_code) = exit_code {
let mut v: Vec<_> = exit_code.collect();
if let Some(v) = v.pop() {
let break_loop = !matches!(v.as_i64(), Ok(0));
stack.add_env_var("LAST_EXIT_CODE".into(), v);
if break_loop {
input = PipelineData::empty();
break;
}
}
}
}
_ => input.drain()?,
}
input = PipelineData::empty()
}
}
Ok(input)
}
pub fn eval_subexpression(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
eval_block(engine_state, stack, block, input, true, false)
}
pub fn eval_variable(
engine_state: &EngineState,
stack: &Stack,
var_id: VarId,
span: Span,
) -> Result<Value, ShellError> {
match var_id {
// $nu
nu_protocol::NU_VARIABLE_ID => {
if let Some(val) = engine_state.get_constant(var_id) {
Ok(val.clone())
} else {
Err(ShellError::VariableNotFoundAtRuntime { span })
}
}
// $env
ENV_VARIABLE_ID => {
let env_vars = stack.get_env_vars(engine_state);
let env_columns = env_vars.keys();
let env_values = env_vars.values();
let mut pairs = env_columns
.map(|x| x.to_string())
.zip(env_values.cloned())