rustleaf 0.1.0

A simple programming language interpreter written in 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

use crate::core::{RustValue, Value};
use crate::eval::{ControlFlow, ErrorKind, EvalResult, Evaluator};
use anyhow::anyhow;

#[derive(Debug, Clone)]
pub struct EvalSetAttr {
    pub obj_expr: Value,
    pub attr_name: String,
    pub value_expr: Value,
}

#[crate::rust_value_any]
impl RustValue for EvalSetAttr {
    fn dyn_clone(&self) -> Box<dyn RustValue> {
        Box::new(self.clone())
    }
    fn eval(&self, evaluator: &mut Evaluator) -> anyhow::Result<EvalResult> {
        let mut obj_value = match self.obj_expr.eval(evaluator)? {
            Ok(val) => val,
            Err(e) => return Ok(Err(e)),
        };
        let new_value = match self.value_expr.eval(evaluator)? {
            Ok(val) => val,
            Err(e) => return Ok(Err(e)),
        };

        match obj_value.set_attr(&self.attr_name, new_value) {
            Ok(_) => Ok(Ok(Value::Unit)),
            Err(err) => Ok(Err(ControlFlow::Error(ErrorKind::SystemError(anyhow!(
                err
            ))))),
        }
    }

    fn str(&self) -> String {
        format!(
            "{}.{} = {}",
            self.obj_expr.str(),
            self.attr_name,
            self.value_expr.str()
        )
    }
}