156 lines
4.3 KiB
Rust
156 lines
4.3 KiB
Rust
use crate::prelude::*;
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use nu_engine::evaluate_baseline_expr;
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use nu_engine::WholeStreamCommand;
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use nu_errors::ShellError;
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use nu_protocol::{
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hir::CapturedBlock,
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hir::{ClassifiedCommand, SpannedExpression},
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Signature, SyntaxShape, Value,
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};
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pub struct Command;
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impl WholeStreamCommand for Command {
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fn name(&self) -> &str {
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"where"
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}
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fn signature(&self) -> Signature {
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Signature::build("where").required(
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"condition",
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SyntaxShape::RowCondition,
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"the condition that must match",
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)
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}
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fn usage(&self) -> &str {
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"Filter table to match the condition."
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}
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fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
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where_command(args)
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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: "List all files in the current directory with sizes greater than 2kb",
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example: "ls | where size > 2kb",
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result: None,
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},
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Example {
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description: "List only the files in the current directory",
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example: "ls | where type == File",
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result: None,
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},
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Example {
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description: "List all files with names that contain \"Car\"",
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example: "ls | where name =~ \"Car\"",
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result: None,
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},
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Example {
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description: "List all files that were modified in the last two weeks",
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example: "ls | where modified <= 2wk",
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result: None,
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},
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]
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}
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}
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fn where_command(args: CommandArgs) -> Result<OutputStream, ShellError> {
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let context = Arc::new(EvaluationContext::from_args(&args));
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let tag = args.call_info.name_tag.clone();
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let args = args.evaluate_once()?;
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let block: CapturedBlock = args.req(0)?;
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let condition = {
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if block.block.block.len() != 1 {
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return Err(ShellError::labeled_error(
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"Expected a condition",
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"expected a condition",
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tag,
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));
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}
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match block.block.block[0].pipelines.get(0) {
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Some(item) => match item.list.get(0) {
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Some(ClassifiedCommand::Expr(expr)) => expr.clone(),
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_ => {
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return Err(ShellError::labeled_error(
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"Expected a condition",
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"expected a condition",
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tag,
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));
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}
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},
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None => {
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return Err(ShellError::labeled_error(
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"Expected a condition",
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"expected a condition",
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tag,
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));
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}
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}
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};
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Ok(WhereIterator {
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condition,
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context,
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input: args.input,
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block,
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}
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.to_output_stream())
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}
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#[cfg(test)]
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mod tests {
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use super::Command;
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use super::ShellError;
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#[test]
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fn examples_work_as_expected() -> Result<(), ShellError> {
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use crate::examples::test as test_examples;
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test_examples(Command {})
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}
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}
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struct WhereIterator {
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condition: Box<SpannedExpression>,
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context: Arc<EvaluationContext>,
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input: InputStream,
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block: CapturedBlock,
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}
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impl Iterator for WhereIterator {
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type Item = Value;
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fn next(&mut self) -> Option<Self::Item> {
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while let Some(x) = self.input.next() {
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self.context.scope.enter_scope();
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self.context.scope.add_vars(&self.block.captured.entries);
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if let Some((arg, _)) = self.block.block.params.positional.first() {
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self.context.scope.add_var(arg.name(), x.clone());
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}
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//FIXME: should we use the scope that's brought in as well?
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let condition = evaluate_baseline_expr(&self.condition, &self.context);
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self.context.scope.exit_scope();
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match condition {
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Ok(condition) => match condition.as_bool() {
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Ok(b) => {
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if b {
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return Some(x);
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}
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}
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Err(e) => return Some(Value::error(e)),
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},
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Err(e) => return Some(Value::error(e)),
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}
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}
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None
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}
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}
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