nushell/crates/nu-command/tests/commands/mod.rs
Devyn Cairns 872aa78373
Add interleave command for reading multiple streams in parallel (#11955)
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# Description
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This command mixes input from multiple sources and sends items to the
final stream as soon as they're available. It can be called as part of a
pipeline with input, or it can take multiple closures and mix them that
way.

See `crates/nu-command/tests/commands/interleave.rs` for a practical
example. I imagine this will be most often used to run multiple commands
in parallel and print their outputs line-by-line. A stdlib command could
potentially use `interleave` to make this particular use case easier.

It's quite common to wish that nushell had a command for running things
in the background, and instead of providing job control, this provides
an alternative to some use cases for that by just allowing multiple
commands to run simultaneously and direct their output to the same
place.

This enables certain things that are not possible with `par-each` - for
example, you may wish to run `make` across several projects in parallel:

```nushell
(ls projects).name | par-each { |project| cd $project; make }
```

This works well enough, but the output will only be available after each
`make` command finishes. `interleave` allows you to get each line:

```nushell
interleave ...(
  (ls projects).name | each { |project|
    {
      cd $project
      make | lines | each { |line| {project: $project, out: $line} }
    }
  }
)
```

The result of this is a stream that you could process further - for
example, by saving to a text file.

Note that the closures themselves are not run in parallel. The initial
execution happens serially, and then the streams are consumed in
parallel.

# User-Facing Changes
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helps us keep track of breaking changes. -->

Adds a new command.

# Tests + Formatting
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- 🟢 `toolkit test stdlib`

# After Submitting
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2024-03-01 16:56:37 -06:00

131 lines
1.6 KiB
Rust

mod alias;
mod all;
mod any;
mod append;
mod assignment;
mod break_;
mod cal;
mod cd;
mod compact;
mod complete;
mod config_env_default;
mod config_nu_default;
mod continue_;
mod conversions;
mod cp;
#[cfg(feature = "sqlite")]
mod database;
mod date;
mod debug_info;
mod def;
mod default;
mod detect_columns;
mod do_;
mod drop;
mod du;
mod each;
mod echo;
mod empty;
mod error_make;
mod every;
mod exec;
mod export_def;
mod fill;
mod find;
mod first;
mod flatten;
mod for_;
#[cfg(feature = "extra")]
mod format;
mod generate;
mod get;
mod glob;
mod group_by;
mod hash_;
mod headers;
mod help;
mod histogram;
mod insert;
mod inspect;
mod interleave;
mod into_datetime;
mod into_filesize;
mod into_int;
mod join;
mod last;
mod length;
mod let_;
mod lines;
mod loop_;
mod ls;
mod match_;
mod math;
mod merge;
mod mktemp;
mod move_;
mod mut_;
mod network;
mod nu_check;
mod open;
mod par_each;
mod parse;
mod path;
mod platform;
mod prepend;
mod print;
#[cfg(feature = "sqlite")]
mod query;
mod random;
mod range;
mod redirection;
mod reduce;
mod reject;
mod rename;
mod return_;
mod reverse;
mod rm;
#[cfg(feature = "extra")]
mod roll;
#[cfg(feature = "extra")]
mod rotate;
mod run_external;
mod save;
mod select;
mod semicolon;
mod seq;
mod seq_char;
mod seq_date;
mod skip;
mod sort;
mod sort_by;
mod source_env;
mod split_by;
mod split_column;
mod split_row;
mod str_;
mod table;
mod take;
mod tee;
mod terminal;
mod to_text;
mod touch;
mod transpose;
mod try_;
mod ucp;
#[cfg(unix)]
mod ulimit;
mod umkdir;
mod uniq;
mod uniq_by;
mod update;
mod upsert;
mod url;
mod use_;
mod where_;
#[cfg(feature = "which-support")]
mod which;
mod while_;
mod with_env;
mod wrap;
mod zip;