nushell/crates/nu-cmd-lang/src/core_commands/def.rs
2023-10-02 21:13:31 +03:00

74 lines
2.5 KiB
Rust

use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, PipelineData, ShellError, Signature, SyntaxShape, Type, Value,
};
#[derive(Clone)]
pub struct Def;
impl Command for Def {
fn name(&self) -> &str {
"def"
}
fn usage(&self) -> &str {
"Define a custom command."
}
fn signature(&self) -> nu_protocol::Signature {
Signature::build("def")
.input_output_types(vec![(Type::Nothing, Type::Nothing)])
.required("def_name", SyntaxShape::String, "command name")
.required("params", SyntaxShape::Signature, "parameters")
.required("block", SyntaxShape::Closure(None), "body of the definition")
.switch("env", "keep the environment defined inside the command", None)
.switch("wrapped", "treat unknown flags and arguments as strings (requires ...rest-like parameter in signature)", None)
.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<PipelineData, ShellError> {
Ok(PipelineData::empty())
}
fn examples(&self) -> Vec<Example> {
vec![
Example {
description: "Define a command and run it",
example: r#"def say-hi [] { echo 'hi' }; say-hi"#,
result: Some(Value::test_string("hi")),
},
Example {
description: "Define a command and run it with parameter(s)",
example: r#"def say-sth [sth: string] { echo $sth }; say-sth hi"#,
result: Some(Value::test_string("hi")),
},
Example {
description: "Set environment variable by call a custom command",
example: r#"def --env foo [] { $env.BAR = "BAZ" }; foo; $env.BAR"#,
result: Some(Value::test_string("BAZ")),
},
Example {
description: "Define a custom wrapper for an external command",
example: r#"def --wrapped my-echo [...rest] { echo $rest }; my-echo spam"#,
result: Some(Value::test_list(vec![Value::test_string("spam")])),
},
]
}
}