forked from extern/nushell
5d9e2455f7
# Description This changes the default behaviour of `let` to be able to take a pipeline as its initial value. For example: ``` > let x = "hello world" | str length ``` This is a change from the existing behaviour, where the right hand side is assumed to be an expression. Pipelines are more general, and can be more powerful. My google foo is failing me, but this also fixes this issue: ``` let x = foo ``` Currently, this reads `foo` as a bareword that gets converted to a string rather than running the `foo` command. In practice, this is really annoying and is a really hard to spot bug in a script. # User-Facing Changes BREAKING CHANGE BREAKING CHANGE `let` gains the power to be assigned via a pipeline. However, this changes the behaviour of `let x = foo` from assigning the string "foo" to `$x` to being "run the command `foo` and give the result to `$x`" # Tests + Formatting <!-- Don't forget to add tests that cover your changes. Make sure you've run and fixed any issues with these commands: - `cargo fmt --all -- --check` to check standard code formatting (`cargo fmt --all` applies these changes) - `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect -A clippy::result_large_err` to check that you're using the standard code style - `cargo test --workspace` to check that all tests pass - `cargo run -- crates/nu-std/tests/run.nu` to run the tests for the standard library > **Note** > from `nushell` you can also use the `toolkit` as follows > ```bash > use toolkit.nu # or use an `env_change` hook to activate it automatically > toolkit check pr > ``` --> # After Submitting <!-- If your PR had any user-facing changes, update [the documentation](https://github.com/nushell/nushell.github.io) after the PR is merged, if necessary. This will help us keep the docs up to date. -->
65 lines
1.2 KiB
Rust
65 lines
1.2 KiB
Rust
use nu_test_support::{nu, pipeline};
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#[test]
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fn let_name_builtin_var() {
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let actual = nu!(
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cwd: ".", pipeline(
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r#"
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let in = 3
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"#
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));
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assert!(actual
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.err
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.contains("'in' is the name of a builtin Nushell variable"));
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}
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#[test]
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fn let_doesnt_mutate() {
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let actual = nu!(
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cwd: ".", pipeline(
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r#"
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let i = 3; $i = 4
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"#
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));
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assert!(actual.err.contains("immutable"));
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}
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#[test]
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fn let_takes_pipeline() {
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let actual = nu!(
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cwd: ".", pipeline(
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r#"
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let x = "hello world" | str length; print $x
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"#
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));
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assert_eq!(actual.out, "11");
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}
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#[test]
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fn let_pipeline_allows_in() {
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let actual = nu!(
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cwd: ".", pipeline(
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r#"
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def foo [] { let x = $in | str length; print ($x + 10) }; "hello world" | foo
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"#
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));
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assert_eq!(actual.out, "21");
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}
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#[ignore]
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#[test]
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fn let_with_external_failed() {
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// FIXME: this test hasn't run successfully for a long time. We should
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// bring it back to life at some point.
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let actual = nu!(
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cwd: ".",
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pipeline(r#"let x = nu --testbin outcome_err "aa"; echo fail"#)
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);
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assert!(!actual.out.contains("fail"));
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}
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