python-ast 1.1.0

A library for compiling Python to Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88

use proc_macro2::TokenStream;
use pyo3::{Borrowed, FromPyObject, PyAny, PyResult};
use quote::quote;
use serde::{Deserialize, Serialize};

use crate::{
    CodeGen, CodeGenContext, ExprType, PythonOptions, SymbolTableScopes,
    Node, impl_node_with_positions, extract_list
};

#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
pub struct Dict {
    pub keys: Vec<Option<ExprType>>,
    pub values: Vec<ExprType>,
    pub lineno: Option<usize>,
    pub col_offset: Option<usize>,
    pub end_lineno: Option<usize>,
    pub end_col_offset: Option<usize>,
}

impl<'a, 'py> FromPyObject<'a, 'py> for Dict {
    type Error = pyo3::PyErr;
    fn extract(ob: Borrowed<'a, 'py, PyAny>) -> PyResult<Self> {
        let keys: Vec<Option<ExprType>> = extract_list(&ob, "keys", "dictionary keys")?;
        let values: Vec<ExprType> = extract_list(&ob, "values", "dictionary values")?;
        
        Ok(Dict {
            keys,
            values,
            lineno: ob.lineno(),
            col_offset: ob.col_offset(),
            end_lineno: ob.end_lineno(),
            end_col_offset: ob.end_col_offset(),
        })
    }
}

impl_node_with_positions!(Dict { lineno, col_offset, end_lineno, end_col_offset });

impl CodeGen for Dict {
    type Context = CodeGenContext;
    type Options = PythonOptions;
    type SymbolTable = SymbolTableScopes;

    fn to_rust(
        self,
        ctx: Self::Context,
        options: Self::Options,
        symbols: Self::SymbolTable,
    ) -> Result<TokenStream, Box<dyn std::error::Error>> {
        let mut pairs = Vec::new();
        
        for (key, value) in self.keys.iter().zip(self.values.iter()) {
            match key {
                Some(k) => {
                    let key_tokens = k.clone().to_rust(ctx.clone(), options.clone(), symbols.clone())?;
                    let value_tokens = value.clone().to_rust(ctx.clone(), options.clone(), symbols.clone())?;
                    pairs.push(quote! { (#key_tokens, #value_tokens) });
                }
                None => {
                    // `{**other}` has no direct HashMap-literal equivalent;
                    // fail the conversion rather than emitting invalid Rust.
                    return Err("dictionary unpacking (`{**other}`) is not yet supported \
                                in dict literals"
                        .to_string()
                        .into());
                }
            }
        }
        
        // PyDict (an insertion-ordered map) rather than HashMap: Python
        // dicts preserve insertion order, and keys()/items()/iteration
        // must match.
        Ok(quote! {
            PyDict::from([#(#pairs),*])
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::create_parse_test;

    create_parse_test!(test_empty_dict, "{}", "dict_test.py");
    create_parse_test!(test_simple_dict, "{'a': 1, 'b': 2}", "dict_test.py");
    create_parse_test!(test_dict_with_variables, "{x: y, z: w}", "dict_test.py");
}