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swap parameter order in generate, so the closure can run with no initial value

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This commit is contained in:
WindSoilder 2024-07-17 07:38:46 +08:00
parent b66671d339
commit bb6bf03607
1 changed files with 36 additions and 5 deletions
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41
crates/nu-command/src/generators/generate.rs
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@ -12,12 +12,12 @@ impl Command for Generate {
fn signature(&self) -> Signature {
Signature::build("generate")
.input_output_types(vec![(Type::Nothing, Type::List(Box::new(Type::Any)))])
.required("initial", SyntaxShape::Any, "Initial value.")
.required(
"closure",
SyntaxShape::Closure(Some(vec![SyntaxShape::Any])),
"Generator function.",
)
.optional("initial", SyntaxShape::Any, "Initial value.")
.allow_variants_without_examples(true)
.category(Category::Generators)
}
@ -72,15 +72,16 @@ used as the next argument to the closure, otherwise generation stops.
_input: PipelineData,
) -> Result<PipelineData, ShellError> {
let head = call.head;
let initial: Value = call.req(engine_state, stack, 0)?;
let closure: Closure = call.req(engine_state, stack, 1)?;
let initial: Option<Value> = call.opt(engine_state, stack, 1)?;
let closure: Closure = call.req(engine_state, stack, 0)?;
let block = engine_state.get_block(closure.block_id);
let mut closure = ClosureEval::new(engine_state, stack, closure);
// A type of Option<S> is used to represent state. Invocation
// will stop on None. Using Option<S> allows functions to output
// one final value before stopping.
let mut state = Some(initial);
let mut state = Some(get_initial_state(initial, &block.signature)?);
// let mut state = Some(initial);
let iter = std::iter::from_fn(move || {
let arg = state.take()?;
@ -181,3 +182,33 @@ mod test {
test_examples(Generate {})
}
}
fn get_initial_state(initial: Option<Value>, signature: &Signature) -> Result<Value, ShellError> {
match initial {
Some(v) => Ok(v),
None => {
// the initial state shold be referred from signature
if signature.optional_positional.len() > 0 {
if let Some(v) = &signature.optional_positional[0].default_value {
Ok(v.clone())
} else {
Err(ShellError::GenericError {
error: "".to_string(),
msg: "bb".to_string(),
help: None,
span: None,
inner: vec![],
})
}
} else {
Err(ShellError::GenericError {
error: "aa".to_string(),
msg: "bb".to_string(),
help: None,
span: None,
inner: vec![],
})
}
}
}
}