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use indexmap::IndexMap;
use nu_engine::{ClosureEval, command_prelude::*};
use nu_protocol::engine::Closure;
#[derive(Clone)]
pub struct Rename;
impl Command for Rename {
fn name(&self) -> &str {
"rename"
}
fn signature(&self) -> Signature {
Signature::build("rename")
.input_output_types(vec![
(Type::record(), Type::record()),
(Type::table(), Type::table()),
])
.named(
"column",
SyntaxShape::Record(vec![]),
"column name to be changed",
Some('c'),
)
.named(
"block",
SyntaxShape::Closure(Some(vec![SyntaxShape::Any])),
"A closure to apply changes on each column",
Some('b'),
)
.rest(
"rest",
SyntaxShape::String,
"The new names for the columns.",
)
.category(Category::Filters)
}
fn description(&self) -> &str {
"Creates a new table with columns renamed."
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
rename(engine_state, stack, call, input)
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Rename a column",
example: "[[a, b]; [1, 2]] | rename my_column",
result: Some(Value::test_list(vec![Value::test_record(record! {
"my_column" => Value::test_int(1),
"b" => Value::test_int(2),
})])),
},
Example {
description: "Rename many columns",
example: "[[a, b, c]; [1, 2, 3]] | rename eggs ham bacon",
result: Some(Value::test_list(vec![Value::test_record(record! {
"eggs" => Value::test_int(1),
"ham" => Value::test_int(2),
"bacon" => Value::test_int(3),
})])),
},
Example {
description: "Rename a specific column",
example: "[[a, b, c]; [1, 2, 3]] | rename --column { a: ham }",
result: Some(Value::test_list(vec![Value::test_record(record! {
"ham" => Value::test_int(1),
"b" => Value::test_int(2),
"c" => Value::test_int(3),
})])),
},
Example {
description: "Rename the fields of a record",
example: "{a: 1 b: 2} | rename x y",
result: Some(Value::test_record(record! {
"x" => Value::test_int(1),
"y" => Value::test_int(2),
})),
},
Example {
description: "Rename fields based on a given closure",
example: "{abc: 1, bbc: 2} | rename --block {str replace --all 'b' 'z'}",
result: Some(Value::test_record(record! {
"azc" => Value::test_int(1),
"zzc" => Value::test_int(2),
})),
},
]
}
}
fn rename(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let head = call.head;
let columns: Vec<String> = call.rest(engine_state, stack, 0)?;
let specified_column: Option<Record> = call.get_flag(engine_state, stack, "column")?;
// convert from Record to HashMap for easily query.
let specified_column: Option<IndexMap<String, String>> = match specified_column {
Some(query) => {
let mut columns = IndexMap::new();
for (col, val) in query {
let val_span = val.span();
match val {
Value::String { val, .. } => {
columns.insert(col, val);
}
_ => {
return Err(ShellError::TypeMismatch {
err_message: "new column name must be a string".to_owned(),
span: val_span,
});
}
}
}
if columns.is_empty() {
return Err(ShellError::TypeMismatch {
err_message: "The column info cannot be empty".to_owned(),
span: call.head,
});
}
Some(columns)
}
None => None,
};
let closure: Option<Closure> = call.get_flag(engine_state, stack, "block")?;
let mut closure = closure.map(|closure| ClosureEval::new(engine_state, stack, closure));
let metadata = input.metadata();
input
.map(
move |item| {
let span = item.span();
match item {
Value::Record { val: record, .. } => {
let record = if let Some(closure) = &mut closure {
record
.into_owned()
.into_iter()
.map(|(col, val)| {
let col = Value::string(col, span);
let data = closure.run_with_value(col)?;
let col = data.collect_string_strict(span)?.0;
Ok((col, val))
})
.collect::<Result<Record, _>>()
} else {
match &specified_column {
Some(columns) => {
// record columns are unique so we can track the number
// of renamed columns to check if any were missed
let mut renamed = 0;
let record = record
.into_owned()
.into_iter()
.map(|(col, val)| {
let col = if let Some(col) = columns.get(&col) {
renamed += 1;
col.clone()
} else {
col
};
(col, val)
})
.collect::<Record>();
let missing_column = if renamed < columns.len() {
columns.iter().find_map(|(col, new_col)| {
(!record.contains(new_col)).then_some(col)
})
} else {
None
};
if let Some(missing) = missing_column {
Err(ShellError::UnsupportedInput {
msg: format!(
"The column '{missing}' does not exist in the input"
),
input: "value originated from here".into(),
msg_span: head,
input_span: span,
})
} else {
Ok(record)
}
}
None => Ok(record
.into_owned()
.into_iter()
.enumerate()
.map(|(i, (col, val))| {
(columns.get(i).cloned().unwrap_or(col), val)
})
.collect()),
}
};
match record {
Ok(record) => Value::record(record, span),
Err(err) => Value::error(err, span),
}
}
// Propagate errors by explicitly matching them before the final case.
Value::Error { .. } => item,
other => Value::error(
ShellError::OnlySupportsThisInputType {
exp_input_type: "record".into(),
wrong_type: other.get_type().to_string(),
dst_span: head,
src_span: other.span(),
},
head,
),
}
},
engine_state.signals(),
)
.map(|data| data.set_metadata(metadata))
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(Rename {})
}
}