forked from extern/nushell
522a828687
* Refactor InputStream and affected commands. First, making `values` private and leaning on the `Stream` implementation makes consumes of `InputStream` less likely to have to change in the future, if we change what an `InputStream` is internally. Second, we're dropping `Option<InputStream>` as the input to pipelines, internals, and externals. Instead, `InputStream.is_empty` can be used to check for "emptiness". Empty streams are typically only ever used as the first input to a pipeline. * Add run_external internal command. We want to push external commands closer to internal commands, eventually eliminating the concept of "external" completely. This means we can consolidate a couple of things: - Variable evaluation (for example, `$it`, `$nu`, alias vars) - Behaviour of whole stream vs per-item external execution It should also make it easier for us to start introducing argument signatures for external commands, * Update run_external.rs * Update run_external.rs * Update run_external.rs * Update run_external.rs Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
81 lines
2.8 KiB
Rust
81 lines
2.8 KiB
Rust
use crate::commands::WholeStreamCommand;
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use crate::context::CommandRegistry;
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use crate::prelude::*;
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use futures::stream::StreamExt;
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use indexmap::IndexMap;
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use nu_errors::ShellError;
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use nu_protocol::Dictionary;
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use nu_protocol::{ReturnSuccess, Signature, UntaggedValue, Value};
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pub struct Headers;
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#[derive(Deserialize)]
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pub struct HeadersArgs {}
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impl WholeStreamCommand for Headers {
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fn name(&self) -> &str {
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"headers"
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}
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fn signature(&self) -> Signature {
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Signature::build("headers")
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}
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fn usage(&self) -> &str {
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"Use the first row of the table as column names"
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}
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fn run(
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&self,
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args: CommandArgs,
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registry: &CommandRegistry,
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) -> Result<OutputStream, ShellError> {
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args.process(registry, headers)?.run()
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}
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}
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pub fn headers(
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HeadersArgs {}: HeadersArgs,
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RunnableContext { input, .. }: RunnableContext,
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) -> Result<OutputStream, ShellError> {
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let stream = async_stream! {
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let rows: Vec<Value> = input.collect().await;
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if rows.len() < 1 {
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yield Err(ShellError::untagged_runtime_error("Couldn't find headers, was the input a properly formatted, non-empty table?"));
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}
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//the headers are the first row in the table
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let headers: Vec<String> = match &rows[0].value {
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UntaggedValue::Row(d) => {
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Ok(d.entries.iter().map(|(k, v)| {
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match v.as_string() {
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Ok(s) => s,
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Err(_) => { //If a cell that should contain a header name is empty, we name the column Column[index]
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match d.entries.get_full(k) {
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Some((index, _, _)) => format!("Column{}", index),
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None => "unknownColumn".to_string()
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}
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}
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}
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}).collect())
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}
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_ => Err(ShellError::unexpected_eof("Could not get headers, is the table empty?", rows[0].tag.span))
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}?;
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//Each row is a dictionary with the headers as keys
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for r in rows.iter().skip(1) {
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match &r.value {
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UntaggedValue::Row(d) => {
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let mut i = 0;
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let mut entries = IndexMap::new();
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for (_, v) in d.entries.iter() {
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entries.insert(headers[i].clone(), v.clone());
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i += 1;
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}
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yield Ok(ReturnSuccess::Value(UntaggedValue::Row(Dictionary{entries}).into_value(r.tag.clone())))
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}
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_ => yield Err(ShellError::unexpected_eof("Couldn't iterate through rows, was the input a properly formatted table?", r.tag.span))
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}
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}
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};
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Ok(stream.to_output_stream())
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}
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