132ikl eb9eb09ac5
Make parse simple patterns ignore fields with placeholder (_) (#15873)
# Description
Simple `parse` patterns let you quickly put together simple parsers, but
sometimes you aren't actually interested in some of the output (such as
variable whitespace). This PR lets you use `{_}` to discard part of the
input.

Example:
```nushell
"hello world" | parse "{foo} {_}"
# => ╭───┬───────╮
# => │ # │  foo  │
# => ├───┼───────┤
# => │ 0 │ hello │
# => ╰───┴───────╯
```

here's a simple parser for the `apropops` using the `_` placeholder to
discard the variable whitespace, without needing to resort to a full
regex pattern:

```nushell
apropos linux | parse "{name} ({section}) {_}- {topic}"
# => ╭───┬───────────────────────────────────────┬─────────┬─────────────────────────────────────────────────────────────────────╮
# => │ # │                 name                  │ section │                                topic                                │
# => ├───┼───────────────────────────────────────┼─────────┼─────────────────────────────────────────────────────────────────────┤
# => │ 0 │ PAM                                   │ 8       │ Pluggable Authentication Modules for Linux                          │
# => │ 1 │ aarch64-linux-gnu-addr2line           │ 1       │ convert addresses or symbol+offset into file names and line numbers │
# => │ 2 │ ...                                   │ ...     │ ...                                                                 │
# => │ 3 │ xcb_selinux_set_window_create_context │ 3       │ (unknown subject)                                                   │
# => │ 4 │ xorriso-dd-target                     │ 1       │ Device evaluator and disk image copier for GNU/Linux                │
# => ╰───┴───────────────────────────────────────┴─────────┴─────────────────────────────────────────────────────────────────────╯
```

# User-Facing Changes
* `parse` simple patterns can now discard input using `{_}`

# Tests + Formatting
N/A

# After Submitting
N/A
2025-06-03 03:11:05 +03:00

237 lines
6.5 KiB
Rust

use nu_test_support::fs::Stub;
use nu_test_support::playground::Playground;
use nu_test_support::{nu, pipeline};
mod simple {
use super::*;
#[test]
fn extracts_fields_from_the_given_the_pattern() {
Playground::setup("parse_test_simple_1", |dirs, sandbox| {
sandbox.with_files(&[Stub::FileWithContentToBeTrimmed(
"key_value_separated_arepa_ingredients.txt",
r#"
VAR1=Cheese
VAR2=JTParsed
VAR3=NushellSecretIngredient
"#,
)]);
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
open key_value_separated_arepa_ingredients.txt
| lines
| each { |it| echo $it | parse "{Name}={Value}" }
| flatten
| get 1
| get Value
"#
));
assert_eq!(actual.out, "JTParsed");
})
}
#[test]
fn double_open_curly_evaluates_to_a_single_curly() {
let actual = nu!(pipeline(
r#"
echo "{abc}123"
| parse "{{abc}{name}"
| get name.0
"#
));
assert_eq!(actual.out, "123");
}
#[test]
fn properly_escapes_text() {
let actual = nu!(pipeline(
r#"
echo "(abc)123"
| parse "(abc){name}"
| get name.0
"#
));
assert_eq!(actual.out, "123");
}
#[test]
fn properly_captures_empty_column() {
let actual = nu!(pipeline(
r#"
echo ["1:INFO:component:all is well" "2:ERROR::something bad happened"]
| parse "{timestamp}:{level}:{tag}:{entry}"
| get entry
| get 1
"#
));
assert_eq!(actual.out, "something bad happened");
}
#[test]
fn errors_when_missing_closing_brace() {
let actual = nu!(pipeline(
r#"
echo "(abc)123"
| parse "(abc){name"
| get name
"#
));
assert!(
actual
.err
.contains("Found opening `{` without an associated closing `}`")
);
}
#[test]
fn ignore_multiple_placeholder() {
let actual = nu!(pipeline(
r#"
echo ["1:INFO:component:all is well" "2:ERROR::something bad happened"]
| parse "{_}:{level}:{_}:{entry}"
| to json -r
"#
));
assert_eq!(
actual.out,
r#"[{"level":"INFO","entry":"all is well"},{"level":"ERROR","entry":"something bad happened"}]"#
);
}
}
mod regex {
use super::*;
fn nushell_git_log_oneline<'a>() -> Vec<Stub<'a>> {
vec![Stub::FileWithContentToBeTrimmed(
"nushell_git_log_oneline.txt",
r#"
ae87582c Fix missing invocation errors (#1846)
b89976da let format access variables also (#1842)
"#,
)]
}
#[test]
fn extracts_fields_with_all_named_groups() {
Playground::setup("parse_test_regex_1", |dirs, sandbox| {
sandbox.with_files(&nushell_git_log_oneline());
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
open nushell_git_log_oneline.txt
| parse --regex "(?P<Hash>\\w+) (?P<Message>.+) \\(#(?P<PR>\\d+)\\)"
| get 1
| get PR
"#
));
assert_eq!(actual.out, "1842");
})
}
#[test]
fn extracts_fields_with_all_unnamed_groups() {
Playground::setup("parse_test_regex_2", |dirs, sandbox| {
sandbox.with_files(&nushell_git_log_oneline());
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
open nushell_git_log_oneline.txt
| parse --regex "(\\w+) (.+) \\(#(\\d+)\\)"
| get 1
| get capture0
"#
));
assert_eq!(actual.out, "b89976da");
})
}
#[test]
fn extracts_fields_with_named_and_unnamed_groups() {
Playground::setup("parse_test_regex_3", |dirs, sandbox| {
sandbox.with_files(&nushell_git_log_oneline());
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
open nushell_git_log_oneline.txt
| parse --regex "(?P<Hash>\\w+) (.+) \\(#(?P<PR>\\d+)\\)"
| get 1
| get capture1
"#
));
assert_eq!(actual.out, "let format access variables also");
})
}
#[test]
fn errors_with_invalid_regex() {
Playground::setup("parse_test_regex_1", |dirs, sandbox| {
sandbox.with_files(&nushell_git_log_oneline());
let actual = nu!(
cwd: dirs.test(), pipeline(
r#"
open nushell_git_log_oneline.txt
| parse --regex "(?P<Hash>\\w+ unfinished capture group"
"#
));
assert!(
actual
.err
.contains("Opening parenthesis without closing parenthesis")
);
})
}
#[test]
fn parse_works_with_streaming() {
let actual =
nu!(r#"seq char a z | each {|c| $c + " a"} | parse '{letter} {a}' | describe"#);
assert_eq!(actual.out, "table<letter: string, a: string> (stream)")
}
#[test]
fn parse_does_not_truncate_list_streams() {
let actual = nu!(pipeline(
r#"
[a b c]
| each {|x| $x}
| parse --regex "[ac]"
| length
"#
));
assert_eq!(actual.out, "2");
}
#[test]
fn parse_handles_external_stream_chunking() {
Playground::setup("parse_test_streaming_1", |dirs, sandbox| {
let data: String = "abcdefghijklmnopqrstuvwxyz".repeat(1000);
sandbox.with_files(&[Stub::FileWithContent("data.txt", &data)]);
let actual = nu!(
cwd: dirs.test(),
r#"open data.txt | parse --regex "(abcdefghijklmnopqrstuvwxyz)" | length"#
);
assert_eq!(actual.out, "1000");
})
}
}