Add for..in command (#3504)

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JT 2021-05-28 10:32:45 +12:00 committed by GitHub
parent fe348e236f
commit 872f6166e1
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4 changed files with 226 additions and 12 deletions

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@ -46,6 +46,7 @@ pub(crate) mod exec;
pub(crate) mod exit;
pub(crate) mod first;
pub(crate) mod flatten;
pub(crate) mod for_in;
pub(crate) mod format;
pub(crate) mod from;
pub(crate) mod from_csv;
@ -173,6 +174,7 @@ pub(crate) use each::EachGroup;
pub(crate) use each::EachWindow;
pub(crate) use echo::Echo;
pub(crate) use empty::Command as Empty;
pub(crate) use for_in::ForIn;
pub(crate) use if_::If;
pub(crate) use into::Into;
pub(crate) use into::IntoBinary;

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@ -158,6 +158,7 @@ pub fn create_default_context(interactive: bool) -> Result<EvaluationContext, Bo
whole_stream_command(EachGroup),
whole_stream_command(EachWindow),
whole_stream_command(Empty),
whole_stream_command(ForIn),
// Table manipulation
whole_stream_command(Flatten),
whole_stream_command(Move),

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@ -39,13 +39,8 @@ impl WholeStreamCommand for Echo {
}
}
fn echo(args: CommandArgs) -> Result<InputStream, ShellError> {
let args = args.evaluate_once()?;
let rest: Vec<Value> = args.rest(0)?;
let stream = rest.into_iter().map(|i| match i.as_string() {
Ok(s) => InputStream::one(UntaggedValue::string(s).into_value(i.tag.clone())),
_ => match i {
pub fn expand_value_to_stream(v: Value) -> InputStream {
match v {
Value {
value: UntaggedValue::Table(table),
..
@ -55,7 +50,16 @@ fn echo(args: CommandArgs) -> Result<InputStream, ShellError> {
tag,
} => InputStream::from_stream(RangeIterator::new(*range, tag)),
x => InputStream::one(x),
},
}
}
fn echo(args: CommandArgs) -> Result<InputStream, ShellError> {
let args = args.evaluate_once()?;
let rest: Vec<Value> = args.rest(0)?;
let stream = rest.into_iter().map(|i| match i.as_string() {
Ok(s) => InputStream::one(UntaggedValue::string(s).into_value(i.tag)),
_ => expand_value_to_stream(i),
});
Ok(InputStream::from_stream(stream.flatten()))

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@ -0,0 +1,207 @@
use crate::prelude::*;
use nu_engine::{evaluate_baseline_expr, run_block};
use nu_engine::{FromValue, WholeStreamCommand};
use nu_errors::ShellError;
use nu_protocol::{
hir::{CapturedBlock, ExternalRedirection, Literal},
Signature, SyntaxShape, TaggedDictBuilder, UntaggedValue, Value,
};
pub struct ForIn;
impl WholeStreamCommand for ForIn {
fn name(&self) -> &str {
"for"
}
fn signature(&self) -> Signature {
Signature::build("for")
.required("var", SyntaxShape::String, "the name of the variable")
.required("in", SyntaxShape::String, "the word 'in'")
.required("value", SyntaxShape::Any, "the value we want to iterate")
.required("block", SyntaxShape::Block, "the block to run on each item")
.switch(
"numbered",
"returned a numbered item ($it.index and $it.item)",
Some('n'),
)
}
fn usage(&self) -> &str {
"Run a block on each row of the table."
}
fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
for_in(args)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Echo the square of each integer",
example: "for x in [1 2 3] { $x * $x }",
result: Some(vec![
UntaggedValue::int(1).into(),
UntaggedValue::int(4).into(),
UntaggedValue::int(9).into(),
]),
},
Example {
description: "Echo the square of each integer",
example: "for x in 1..3 { $x }",
result: Some(vec![
UntaggedValue::int(1).into(),
UntaggedValue::int(2).into(),
UntaggedValue::int(3).into(),
]),
},
Example {
description: "Echo the square of each integer",
example: "for x in 1..3 { $x }",
result: Some(vec![
UntaggedValue::int(1).into(),
UntaggedValue::int(2).into(),
UntaggedValue::int(3).into(),
]),
},
Example {
description: "Number each item and echo a message",
example: "for $it in ['bob' 'fred'] --numbered { $\"($it.index) is ($it.item)\" }",
result: Some(vec![Value::from("0 is bob"), Value::from("1 is fred")]),
},
]
}
}
pub fn process_row(
captured_block: Arc<Box<CapturedBlock>>,
context: Arc<EvaluationContext>,
input: Value,
var_name: &str,
external_redirection: ExternalRedirection,
) -> Result<OutputStream, ShellError> {
let input_clone = input.clone();
// When we process a row, we need to know whether the block wants to have the contents of the row as
// a parameter to the block (so it gets assigned to a variable that can be used inside the block) or
// if it wants the contents as as an input stream
let input_stream = if !captured_block.block.params.positional.is_empty() {
InputStream::empty()
} else {
vec![Ok(input_clone)].into_iter().to_input_stream()
};
context.scope.enter_scope();
context.scope.add_vars(&captured_block.captured.entries);
context.scope.add_var(var_name, input);
let result = run_block(
&captured_block.block,
&*context,
input_stream,
external_redirection,
);
context.scope.exit_scope();
result
}
pub(crate) fn make_indexed_item(index: usize, item: Value) -> Value {
let mut dict = TaggedDictBuilder::new(item.tag());
dict.insert_untagged("index", UntaggedValue::int(index as i64));
dict.insert_value("item", item);
dict.into_value()
}
fn for_in(raw_args: CommandArgs) -> Result<OutputStream, ShellError> {
let context = Arc::new(EvaluationContext::from_args(&raw_args));
let external_redirection = raw_args.call_info.args.external_redirection;
//let args = raw_args.evaluate_once()?;
let numbered: bool = raw_args.call_info.switch_present("numbered");
let positional = raw_args
.call_info
.args
.positional
.expect("Internal error: type checker should require args");
let mut var_name: String = match &positional[0].expr {
nu_protocol::hir::Expression::FullColumnPath(path) => match &path.head.expr {
nu_protocol::hir::Expression::Variable(v, _) => v,
x => {
return Err(ShellError::labeled_error(
format!("Expected a variable (got {:?})", x),
"expected a variable",
positional[0].span,
))
}
},
nu_protocol::hir::Expression::Literal(Literal::String(x)) => x,
x => {
return Err(ShellError::labeled_error(
format!("Expected a variable (got {:?})", x),
"expected a variable",
positional[0].span,
))
}
}
.to_string();
let rhs = evaluate_baseline_expr(&positional[2], &context)?;
let block: CapturedBlock =
FromValue::from_value(&evaluate_baseline_expr(&positional[3], &context)?)?;
if !var_name.starts_with('$') {
var_name = format!("${}", var_name);
}
let input = crate::commands::echo::expand_value_to_stream(rhs);
let block = Arc::new(Box::new(block));
if numbered {
Ok(input
.enumerate()
.map(move |input| {
let block = block.clone();
let context = context.clone();
let row = make_indexed_item(input.0, input.1);
match process_row(block, context, row, &var_name, external_redirection) {
Ok(s) => s,
Err(e) => OutputStream::one(Value::error(e)),
}
})
.flatten()
.to_output_stream())
} else {
Ok(input
.map(move |input| {
let block = block.clone();
let context = context.clone();
match process_row(block, context, input, &var_name, external_redirection) {
Ok(s) => s,
Err(e) => OutputStream::one(Value::error(e)),
}
})
.flatten()
.to_output_stream())
}
}
#[cfg(test)]
mod tests {
use super::ForIn;
use super::ShellError;
#[test]
fn examples_work_as_expected() -> Result<(), ShellError> {
use crate::examples::test as test_examples;
test_examples(ForIn {})
}
}