use crate::env::Environment;
use crate::error::Error;
use crate::repr::Expr;

mod env;
pub mod error;
mod eval;
mod funcs;
mod lex;
mod parse;
pub mod repr;

pub struct Furs {
    env: Environment,
}

impl Furs {
    pub fn new() -> Furs {
        let mut env = Environment::new();
        funcs::register(&mut env);
        Furs { env }
    }

    pub fn eval(&mut self, input: &str) -> Result<Expr, Error> {
        let mut tokens = lex::lex(input);
        let ast = parse::parse(&mut tokens)?;
        eval::eval(ast, &mut self.env)
    }
}

#[macro_use]
mod macros {
    /// Similar to vec!, but for LinkedList. Mainly used when writing unit tests.
    #[macro_export]
    macro_rules! list {
        () => {
            std::collections::LinkedList::new();
        };
        ( $( $x:expr ),+ ) => {
            {
                use std::collections::LinkedList;
                let mut temp_list = LinkedList::new();
                $(
                    temp_list.push_back($x);
                )+
                    temp_list
            }
        };
    }
}