ksl 0.1.5

KSL core library and interpreter
Documentation
use crate::{
    Environment,
    builtin::BiMathFunctionType,
    eval::apply::eval_apply,
    is_number_eq,
    value::Value,
};

pub(crate) fn builtin(
    args: &[Value],
    func_type: BiMathFunctionType,
    env: &Environment,
) -> Option<(Value, Environment)> {
    if let [v1, v2] = &args[..] {
        match (eval_apply(v1, env), eval_apply(v2, env)) {
            (Some((Value::Number(n1), _)), Some((Value::Number(n2), _))) => Some((
                Value::Number(match func_type {
                    BiMathFunctionType::Div => {
                        if is_number_eq(n2, 0.0) {
                            eprintln!(concat!(
                                "Error[ksl::builtin::Div]: ",
                                "Division by zero."
                            ));
                            return None;
                        } else {
                            n1 / n2
                        }
                    }
                    BiMathFunctionType::Power => n1.powf(n2),
                    BiMathFunctionType::Sub => n1 - n2,
                }),
                Environment::new(),
            )),
            (Some((e1, _)), Some((e2, _))) => {
                eprintln!(
                    concat!(
                        "Error[ksl::builtin::<{:?}>]: ",
                        "Only accepts 2 numbers, but {:?} was passed."
                    ),
                    func_type,
                    (e1, e2)
                );
                None
            }
            _ => {
                eprintln!(
                    concat!(
                        "Error[ksl::builtin::<{:?}>]: ",
                        "Cannot evaluate expression {:?}."
                    ),
                    func_type,
                    (v1, v2)
                );
                None
            }
        }
    } else {
        eprintln!(
            concat!(
                "Error[ksl::builtin::<{:?}>]: ",
                "Only accepts 2 arguments, but {} were passed."
            ),
            func_type,
            args.len()
        );
        None
    }
}