ksl 0.1.30

KSL core library and interpreter
Documentation
//! # ksl::builtin::fun
//!
//! Built-in function `Fun`.

use crate::{Environment, value::Value};

pub(crate) fn builtin(args: &[Value], env: Environment) -> Result<Value, std::sync::Arc<str>> {
    if let [params_val, func_body] = args {
        let params = match params_val {
            Value::List(symbols) => {
                let mut symbol_list = Vec::with_capacity(symbols.len());
                for param in symbols.iter() {
                    match param {
                        Value::Symbol(sym) => {
                            symbol_list.push(sym.clone());
                        }
                        e => {
                            return Err(std::sync::Arc::from(format!(
                                concat!(
                                    "Error[ksl::builtin::Fun]: ",
                                    "Expected a symbol, but got: `{}`."
                                ),
                                e
                            )));
                        }
                    }
                }
                symbol_list
            }
            e => {
                return Err(std::sync::Arc::from(format!(
                    concat!(
                        "Error[ksl::builtin::Fun]: ",
                        "Expected a list, but got: `{}`."
                    ),
                    e
                )));
            }
        };
        Ok(Value::Lambda(
            params,
            std::sync::Arc::new(func_body.clone()),
            env,
        ))
    } else {
        Err(std::sync::Arc::from(format!(
            concat!(
                "Error[ksl::builtin::Fun]: ",
                "Expected 2 parameters, but {} were passed."
            ),
            args.len()
        )))
    }
}