qalam 0.3.1

Interpreter for the Qalam programming language. Qalam is a dead-simple, Urdu inspired, interpreted programming langauge.
Documentation 
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use crate::ast::stmt::Stmt;
use crate::callable::instance::QalamInstance;
use crate::callable::QalamCallable;
use crate::environment::Environment;
use crate::error::RuntimeError;
use crate::hashable::HashableRcRefCell;
use crate::interpreter::Interpreter;
use crate::literal::Literal;
use crate::token::Token;
use std::cell::RefCell;
use std::rc::Rc;

#[derive(Debug, Clone)]
pub struct QalamFunction {
    pub declaration: Stmt,
    pub closure: Rc<RefCell<Environment>>,
    pub is_initializer: bool,
}

impl QalamFunction {
    pub fn init(
        declaration: Stmt,
        closure: Rc<RefCell<Environment>>,
        is_initializer: bool,
    ) -> Self {
        Self {
            declaration,
            closure,
            is_initializer,
        }
    }

    pub fn bind(&self, instance: HashableRcRefCell<QalamInstance>) -> Self {
        let mut env = Environment::init(Some(self.closure.clone()));
        env.define("yeh".to_string(), Some(Literal::Instance(instance)));
        return Self::init(
            self.declaration.clone(),
            Rc::new(RefCell::new(env)),
            self.is_initializer,
        );
    }
}

impl QalamCallable for QalamFunction {
    fn call(
        &mut self,
        interpreter: &mut Interpreter,
        arguments: Vec<Option<Literal>>,
        paren: &Token,
    ) -> Result<Option<Literal>, RuntimeError> {
        // let env = EnvironmentContainer::init(Some(self.closure.clone()));
        let env = Rc::new(RefCell::new(Environment::init(Some(self.closure.clone()))));
        // println!("at line {}, env: {:?}", paren.line, env);
        match &mut self.declaration {
            Stmt::Function {
                name: _,
                params,
                body,
            } => {
                for i in 0..params.len() {
                    let param_name = &params[i].lexeme;
                    let arg = &arguments[i];
                    env.borrow_mut().define(param_name.to_owned(), arg.clone());
                }
                match interpreter.execute_block(body, env) {
                    Ok(_) => {}
                    Err(e) => {
                        if e.message == String::from("dummy") {
                            if self.is_initializer {
                                return Ok(Environment::get_at(
                                    self.closure.clone(),
                                    0,
                                    "yeh".to_string(),
                                )?);
                            }
                            return Ok(e.return_value);
                        } else {
                            return Err(e);
                        }
                    }
                }
                if self.is_initializer {
                    return Ok(Environment::get_at(
                        self.closure.clone(),
                        0,
                        "yeh".to_string(),
                    )?);
                }
                return Ok(None);
            }
            _ => {
                return Err(RuntimeError::init(
                    paren,
                    String::from("Can only call kaam's!"),
                ))
            }
        }
    }

    fn arity(&self) -> usize {
        match &self.declaration {
            Stmt::Function {
                name: _,
                params,
                body: _,
            } => params.len(),
            _ => 0,
        }
    }

    fn clone_box(&self) -> Box<dyn QalamCallable> {
        return Box::new(self.clone());
    }

    fn to_string(&self) -> String {
        match &self.declaration {
            Stmt::Function {
                name,
                params,
                body: _,
            } => {
                let param_string = params
                    .iter()
                    .map(|t| &t.lexeme)
                    .cloned()
                    .collect::<Vec<String>>()
                    .join(", ");
                return format!("<kaam {}({})>", name.lexeme, param_string);
            }
            _ => {
                return format!("khali");
            }
        }
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
}