nushell/crates/nu-command/src/core_commands/module.rs
JT eaec480f42
Improve empty pipelines (#7383)
# Description

This fix changes pipelines to allow them to actually be empty. Mapping
over empty pipelines gives empty pipelines. Empty pipelines immediately
return `None` when iterated.

This removes a some of where `Span::new(0, 0)` was coming from, though
there are other cases where we still use it.

# User-Facing Changes

None

# 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` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# 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.
2022-12-08 07:31:57 +13:00

73 lines
2.4 KiB
Rust

use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{Category, Example, PipelineData, Signature, Span, SyntaxShape, Type, Value};
#[derive(Clone)]
pub struct Module;
impl Command for Module {
fn name(&self) -> &str {
"module"
}
fn usage(&self) -> &str {
"Define a custom module"
}
fn signature(&self) -> nu_protocol::Signature {
Signature::build("module")
.input_output_types(vec![(Type::Nothing, Type::Nothing)])
.required("module_name", SyntaxShape::String, "module name")
.required("block", SyntaxShape::Block, "body of the module")
.category(Category::Core)
}
fn extra_usage(&self) -> &str {
r#"This command is a parser keyword. For details, check:
https://www.nushell.sh/book/thinking_in_nu.html"#
}
fn is_parser_keyword(&self) -> bool {
true
}
fn run(
&self,
_engine_state: &EngineState,
_stack: &mut Stack,
_call: &Call,
_input: PipelineData,
) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
Ok(PipelineData::empty())
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Define a custom command in a module and call it",
example: r#"module spam { export def foo [] { "foo" } }; use spam foo; foo"#,
result: Some(Value::String {
val: "foo".to_string(),
span: Span::test_data(),
}),
},
Example {
description: "Define an environment variable in a module",
example: r#"module foo { export-env { let-env FOO = "BAZ" } }; use foo; $env.FOO"#,
result: Some(Value::String {
val: "BAZ".to_string(),
span: Span::test_data(),
}),
},
Example {
description: "Define a custom command that participates in the environment in a module and call it",
example: r#"module foo { export def-env bar [] { let-env FOO_BAR = "BAZ" } }; use foo bar; bar; $env.FOO_BAR"#,
result: Some(Value::String {
val: "BAZ".to_string(),
span: Span::test_data(),
}),
},
]
}
}