/* relish: versatile lisp shell
 * Copyright (C) 2021 Aidan Hahn
 *
 * 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 3 of the License, or
 * (at your option) any later version.
 *
 * 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 std::boxed::Box;
use std::collections::HashMap;
use crate::cell::{Ctr, Cell};

/* Mapping between a string token and a tree of Cells
 * The string token can be found in any Ctr::Symbol value
 *
 * Considerations: should I use a structure of cells for this?
 * Current thoughts: if this was a language without proper data types, yes.
 */
pub type VTable = HashMap<String, Cell>;

impl VTable {
    pub fn define(
        &mut self,
        identifier: String,
        var_tree: Box<Cell>
    ) {
        if let Some(boxed_cell) = self.insert(identifier, var_tree) {
            drop(boxed_cell);
        }
    }

    pub fn get(
        &self,
        identifier: String
    ) -> Option<Box<Cell>> {
        self.get(identifier)
    }
}