/** Serene --- Yet an other Lisp
*
* Copyright (c) 2020  Sameer Rahmani <lxsameer@gnu.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
use inkwell::values::PointerValue;
use std::collections::HashMap;

pub struct Scope<'a> {
    parent: Option<Box<Scope<'a>>>,
    symbol_table: HashMap<String, PointerValue<'a>>,
}

impl<'a> Scope<'a> {
    pub fn new(_parent: Option<Scope>) -> Scope {
        let p = match _parent {
            Some(x) => Some(Box::new(x)),
            None => None,
        };

        Scope {
            parent: p,
            symbol_table: HashMap::new(),
        }
    }

    pub fn lookup(&self, key: &str) -> Option<PointerValue> {
        self.symbol_table.get(key).map(|x| *x)
    }

    pub fn insert(&mut self, key: &str, val: PointerValue<'a>) {
        self.symbol_table.insert(key.to_string(), val);
    }
}