python_ast/ast/tree/
lambda.rs

1use proc_macro2::TokenStream;
2use pyo3::{Borrowed, FromPyObject, PyAny, PyResult, types::PyAnyMethods};
3use quote::quote;
4use serde::{Deserialize, Serialize};
5
6use crate::{extraction_failure, 
7    CodeGen, CodeGenContext, ExprType, PythonOptions, SymbolTableScopes,
8    Node, impl_node_with_positions, ParameterList, PyAttributeExtractor
9};
10
11#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
12pub struct Lambda {
13    pub args: ParameterList,
14    pub body: Box<ExprType>,
15    pub lineno: Option<usize>,
16    pub col_offset: Option<usize>,
17    pub end_lineno: Option<usize>,
18    pub end_col_offset: Option<usize>,
19}
20
21impl<'a, 'py> FromPyObject<'a, 'py> for Lambda {
22    type Error = pyo3::PyErr;
23    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> PyResult<Self> {
24        let args = ob.extract_attr_with_context("args", "lambda arguments")?;
25        let body = ob.extract_attr_with_context("body", "lambda body")?;
26        
27        let args = args.extract().map_err(|e| extraction_failure("getting lambda arguments", &ob, e))?;
28        let body = body.extract().map_err(|e| extraction_failure("getting lambda body", &ob, e))?;
29        
30        Ok(Lambda {
31            args,
32            body: Box::new(body),
33            lineno: ob.lineno(),
34            col_offset: ob.col_offset(),
35            end_lineno: ob.end_lineno(),
36            end_col_offset: ob.end_col_offset(),
37        })
38    }
39}
40
41impl_node_with_positions!(Lambda { lineno, col_offset, end_lineno, end_col_offset });
42
43impl CodeGen for Lambda {
44    type Context = CodeGenContext;
45    type Options = PythonOptions;
46    type SymbolTable = SymbolTableScopes;
47
48    fn to_rust(
49        self,
50        ctx: Self::Context,
51        options: Self::Options,
52        symbols: Self::SymbolTable,
53    ) -> Result<TokenStream, Box<dyn std::error::Error>> {
54        // Closure parameters must be bare names — `impl Trait` (which typed
55        // function parameters use) is illegal in closure position; Rust
56        // infers closure parameter types.
57        let params: Vec<_> = self
58            .args
59            .args
60            .iter()
61            .map(|param| crate::safe_ident(&param.arg))
62            .collect();
63        let body = self.body.to_rust(ctx, options, symbols)?;
64
65        Ok(quote! {
66            |#(#params),*| #body
67        })
68    }
69}
70
71#[cfg(test)]
72mod tests {
73    use super::*;
74    use crate::create_parse_test;
75
76    create_parse_test!(test_simple_lambda, "lambda x: x + 1", "lambda_test.py");
77    create_parse_test!(test_lambda_with_args, "lambda x, y: x * y", "lambda_test.py");
78    create_parse_test!(test_lambda_no_args, "lambda: 42", "lambda_test.py");
79}
python_ast/ast/tree/lambda.rs

python_ast/ast/tree/
lambda.rs
