# Description Use `record!` macro instead of defining two separate `vec!` for `cols` and `vals` when appropriate. This visually aligns the key with the value. Further more you don't have to deal with the construction of `Record { cols, vals }` so we can hide the implementation details in the future. ## State Not covering all possible commands yet, also some tests/examples are better expressed by creating cols and vals separately. # User/Developer-Facing Changes The examples and tests should read more natural. No relevant functional change # Bycatch Where I noticed it I replaced usage of `Value` constructors with `Span::test_data()` or `Span::unknown()` to the `Value::test_...` constructors. This should make things more readable and also simplify changes to the `Span` system in the future.
145 lines
4.4 KiB
Rust
145 lines
4.4 KiB
Rust
use nu_engine::CallExt;
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use nu_protocol::{
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ast::Call,
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engine::{Command, EngineState, Stack},
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record, Category, Example, PipelineData, ShellError, Signature, Span, SyntaxShape, Type, Value,
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};
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use crate::dataframe::values::NuExpression;
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use super::super::values::NuDataFrame;
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#[derive(Clone)]
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pub struct ToNu;
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impl Command for ToNu {
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fn name(&self) -> &str {
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"dfr into-nu"
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}
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fn usage(&self) -> &str {
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"Converts a dataframe or an expression into into nushell value for access and exploration."
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}
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fn signature(&self) -> Signature {
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Signature::build(self.name())
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.named(
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"rows",
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SyntaxShape::Number,
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"number of rows to be shown",
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Some('n'),
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)
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.switch("tail", "shows tail rows", Some('t'))
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.input_output_types(vec![
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(Type::Custom("expression".into()), Type::Any),
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(Type::Custom("dataframe".into()), Type::Table(vec![])),
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])
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//.input_output_type(Type::Any, Type::Any)
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.category(Category::Custom("dataframe".into()))
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}
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fn examples(&self) -> Vec<Example> {
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let rec_1 = Value::test_record(record! {
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"index" => Value::test_int(0),
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"a" => Value::test_int(1),
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"b" => Value::test_int(2),
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});
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let rec_2 = Value::test_record(record! {
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"index" => Value::test_int(1),
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"a" => Value::test_int(3),
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"b" => Value::test_int(4),
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});
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let rec_3 = Value::test_record(record! {
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"index" => Value::test_int(2),
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"a" => Value::test_int(3),
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"b" => Value::test_int(4),
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});
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vec![
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Example {
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description: "Shows head rows from dataframe",
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example: "[[a b]; [1 2] [3 4]] | dfr into-df | dfr into-nu",
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result: Some(Value::list(vec![rec_1, rec_2], Span::test_data())),
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},
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Example {
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description: "Shows tail rows from dataframe",
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example: "[[a b]; [1 2] [5 6] [3 4]] | dfr into-df | dfr into-nu --tail --rows 1",
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result: Some(Value::list(vec![rec_3], Span::test_data())),
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},
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Example {
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description: "Convert a col expression into a nushell value",
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example: "dfr col a | dfr into-nu",
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result: Some(Value::test_record(record! {
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"expr" => Value::test_string("column"),
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"value" => Value::test_string("a"),
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})),
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},
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]
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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let value = input.into_value(call.head);
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if NuDataFrame::can_downcast(&value) {
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dataframe_command(engine_state, stack, call, value)
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} else {
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expression_command(call, value)
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}
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}
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}
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fn dataframe_command(
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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input: Value,
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) -> Result<PipelineData, ShellError> {
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let rows: Option<usize> = call.get_flag(engine_state, stack, "rows")?;
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let tail: bool = call.has_flag("tail");
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let df = NuDataFrame::try_from_value(input)?;
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let values = if tail {
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df.tail(rows, call.head)?
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} else {
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// if rows is specified, return those rows, otherwise return everything
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if rows.is_some() {
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df.head(rows, call.head)?
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} else {
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df.head(Some(df.height()), call.head)?
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}
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};
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let value = Value::list(values, call.head);
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Ok(PipelineData::Value(value, None))
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}
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fn expression_command(call: &Call, input: Value) -> Result<PipelineData, ShellError> {
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let expr = NuExpression::try_from_value(input)?;
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let value = expr.to_value(call.head)?;
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Ok(PipelineData::Value(value, None))
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}
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#[cfg(test)]
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mod test {
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use super::super::super::expressions::ExprCol;
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use super::super::super::test_dataframe::test_dataframe;
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use super::*;
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#[test]
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fn test_examples_dataframe_input() {
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test_dataframe(vec![Box::new(ToNu {})])
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}
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#[test]
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fn test_examples_expression_input() {
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test_dataframe(vec![Box::new(ToNu {}), Box::new(ExprCol {})])
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}
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}
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