c747ec75c9
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
190 lines
7.4 KiB
Rust
190 lines
7.4 KiB
Rust
use crate::dataframe::values::{Column, NuDataFrame, NuSchema};
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use nu_engine::command_prelude::*;
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use polars::prelude::*;
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#[derive(Clone)]
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pub struct ToDataFrame;
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impl Command for ToDataFrame {
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fn name(&self) -> &str {
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"dfr into-df"
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}
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fn usage(&self) -> &str {
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"Converts a list, table or record into a dataframe."
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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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"schema",
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SyntaxShape::Record(vec![]),
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r#"Polars Schema in format [{name: str}]. CSV, JSON, and JSONL files"#,
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Some('s'),
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)
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.input_output_type(Type::Any, Type::Custom("dataframe".into()))
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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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vec![
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Example {
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description: "Takes a dictionary and creates a dataframe",
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example: "[[a b];[1 2] [3 4]] | dfr into-df",
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result: Some(
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NuDataFrame::try_from_columns(
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vec![
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Column::new(
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"a".to_string(),
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vec![Value::test_int(1), Value::test_int(3)],
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),
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Column::new(
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"b".to_string(),
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vec![Value::test_int(2), Value::test_int(4)],
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),
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],
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None,
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)
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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},
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Example {
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description: "Takes a list of tables and creates a dataframe",
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example: "[[1 2 a] [3 4 b] [5 6 c]] | dfr into-df",
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result: Some(
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NuDataFrame::try_from_columns(
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vec![
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Column::new(
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"0".to_string(),
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vec![Value::test_int(1), Value::test_int(3), Value::test_int(5)],
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),
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Column::new(
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"1".to_string(),
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vec![Value::test_int(2), Value::test_int(4), Value::test_int(6)],
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),
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Column::new(
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"2".to_string(),
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vec![
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Value::test_string("a"),
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Value::test_string("b"),
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Value::test_string("c"),
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],
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),
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],
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None,
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)
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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},
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Example {
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description: "Takes a list and creates a dataframe",
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example: "[a b c] | dfr into-df",
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result: Some(
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NuDataFrame::try_from_columns(
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vec![Column::new(
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"0".to_string(),
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vec![
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Value::test_string("a"),
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Value::test_string("b"),
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Value::test_string("c"),
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],
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)],
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None,
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)
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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},
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Example {
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description: "Takes a list of booleans and creates a dataframe",
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example: "[true true false] | dfr into-df",
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result: Some(
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NuDataFrame::try_from_columns(
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vec![Column::new(
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"0".to_string(),
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vec![
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Value::test_bool(true),
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Value::test_bool(true),
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Value::test_bool(false),
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],
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)],
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None,
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)
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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},
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Example {
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description: "Convert to a dataframe and provide a schema",
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example: "{a: 1, b: {a: [1 2 3]}, c: [a b c]}| dfr into-df -s {a: u8, b: {a: list<u64>}, c: list<str>}",
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result: Some(
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NuDataFrame::try_from_series(vec![
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Series::new("a", &[1u8]),
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{
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let dtype = DataType::Struct(vec![Field::new("a", DataType::List(Box::new(DataType::UInt64)))]);
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let vals = vec![AnyValue::StructOwned(
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Box::new((vec![AnyValue::List(Series::new("a", &[1u64, 2, 3]))], vec![Field::new("a", DataType::String)]))); 1];
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Series::from_any_values_and_dtype("b", &vals, &dtype, false)
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.expect("Struct series should not fail")
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},
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{
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let dtype = DataType::List(Box::new(DataType::String));
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let vals = vec![AnyValue::List(Series::new("c", &["a", "b", "c"]))];
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Series::from_any_values_and_dtype("c", &vals, &dtype, false)
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.expect("List series should not fail")
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}
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], Span::test_data())
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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),
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},
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Example {
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description: "Convert to a dataframe and provide a schema that adds a new column",
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example: r#"[[a b]; [1 "foo"] [2 "bar"]] | dfr into-df -s {a: u8, b:str, c:i64} | dfr fill-null 3"#,
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result: Some(NuDataFrame::try_from_series(vec![
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Series::new("a", [1u8, 2]),
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Series::new("b", ["foo", "bar"]),
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Series::new("c", [3i64, 3]),
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], Span::test_data())
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.expect("simple df for test should not fail")
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.into_value(Span::test_data()),
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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 maybe_schema = call
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.get_flag(engine_state, stack, "schema")?
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.map(|schema| NuSchema::try_from(&schema))
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.transpose()?;
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let df = NuDataFrame::try_from_iter(input.into_iter(), maybe_schema.clone())?;
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Ok(PipelineData::Value(
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NuDataFrame::into_value(df, call.head),
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None,
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))
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}
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}
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#[cfg(test)]
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mod test {
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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() {
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test_dataframe(vec![Box::new(ToDataFrame {})])
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}
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}
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