forked from extern/nushell
79 lines
2.0 KiB
Rust
79 lines
2.0 KiB
Rust
use nu_engine::eval_expression;
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use nu_protocol::ast::Call;
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use nu_protocol::engine::{Command, EngineState, Stack};
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use nu_protocol::{Category, Example, PipelineData, Signature, SyntaxShape};
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#[derive(Clone)]
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pub struct Let;
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impl Command for Let {
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fn name(&self) -> &str {
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"let"
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}
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fn usage(&self) -> &str {
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"Create a variable and give it a value."
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}
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fn signature(&self) -> nu_protocol::Signature {
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Signature::build("let")
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.required("var_name", SyntaxShape::VarWithOptType, "variable name")
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.required(
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"initial_value",
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SyntaxShape::Keyword(b"=".to_vec(), Box::new(SyntaxShape::Expression)),
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"equals sign followed by value",
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)
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.category(Category::Core)
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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_input: PipelineData,
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) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
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let var_id = call.positional[0]
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.as_var()
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.expect("internal error: missing variable");
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let keyword_expr = call.positional[1]
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.as_keyword()
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.expect("internal error: missing keyword");
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let rhs = eval_expression(engine_state, stack, keyword_expr)?;
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//println!("Adding: {:?} to {}", rhs, var_id);
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stack.add_var(var_id, rhs);
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Ok(PipelineData::new(call.head))
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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description: "Set a variable to a value",
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example: "let x = 10",
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result: None,
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},
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Example {
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description: "Set a variable to the result of an expression",
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example: "let x = 10 + 100",
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result: None,
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},
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]
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn test_examples() {
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use crate::test_examples;
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test_examples(Let {})
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}
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}
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