400 lines
19 KiB
Rust
400 lines
19 KiB
Rust
use super::{Value, Type, Object};
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use super::parser::{ParseTree, ParseError};
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use std::collections::HashMap;
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use std::fmt::Display;
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use std::error::Error;
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use std::io;
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use std::sync::Arc;
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use std::cell::RefCell;
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#[derive(Debug)]
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pub enum RuntimeError {
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ParseError(ParseError),
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NoOverloadForTypes(String, Vec<Value>),
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ImmutableError(String),
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VariableUndefined(String),
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FunctionUndeclared(String),
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FunctionUndefined(String),
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NotAVariable(String),
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ParseFail(String, Type),
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TypeError(Type, Type),
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EmptyArray,
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IO(io::Error),
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}
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impl Display for RuntimeError {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match self {
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Self::ParseError(e) => write!(f, "Parser Error: {e}"),
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Self::NoOverloadForTypes(op, values)
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=> write!(f, "No overload of `{op}` exists for the operands `{}`",
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values.iter().map(|x| format!("{}({x})", x.get_type())).collect::<Vec<_>>().join(", ")),
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Self::ImmutableError(ident) => write!(f, "`{ident}` already exists and cannot be redefined"),
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Self::VariableUndefined(ident) => write!(f, "variable `{ident}` was not defined"),
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Self::FunctionUndeclared(ident) => write!(f, "function `{ident}` was not declared"),
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Self::FunctionUndefined(ident) => write!(f, "function `{ident}` was not defined"),
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Self::NotAVariable(ident) => write!(f, "`{ident}` is a function but was attempted to be used like a variable"),
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Self::ParseFail(s, t) => write!(f, "`\"{s}\"` couldn't be parsed into {}", t),
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Self::IO(e) => write!(f, "{e}"),
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Self::TypeError(left, right) => write!(f, "expected type `{left}` but got type `{right}`"),
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Self::EmptyArray => write!(f, "attempt to access element from an empty array"),
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}
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}
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}
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impl Error for RuntimeError {}
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/// Executes an input of ParseTrees
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pub struct Executor<'a, I>
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where
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I: Iterator<Item = Result<ParseTree, ParseError>>
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{
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exprs: &'a mut I,
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globals: &'a mut HashMap<String, Arc<RefCell<Object>>>,
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locals: HashMap<String, Arc<RefCell<Object>>>,
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}
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impl<'a, I> Executor<'a, I>
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where
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I: Iterator<Item = Result<ParseTree, ParseError>>,
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{
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pub fn new(exprs: &'a mut I, globals: &'a mut HashMap<String, Arc<RefCell<Object>>>) -> Self {
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Self {
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exprs,
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globals,
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locals: HashMap::new(),
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}
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}
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pub fn _add_global(self, k: String, v: Arc<RefCell<Object>>) -> Self {
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self.globals.insert(k, v);
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self
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}
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pub fn locals(mut self, locals: HashMap<String, Arc<RefCell<Object>>>) -> Self {
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self.locals = locals;
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self
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}
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pub fn add_local(mut self, k: String, v: Arc<RefCell<Object>>) -> Self {
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self.locals.insert(k, v);
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self
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}
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fn _get_object(&self, ident: &String) -> Result<&Arc<RefCell<Object>>, RuntimeError> {
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self.locals.get(ident).or(self.globals.get(ident))
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.ok_or(RuntimeError::VariableUndefined(ident.clone()))
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}
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fn get_object_mut(&mut self, ident: &String) -> Result<&mut Arc<RefCell<Object>>, RuntimeError> {
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self.locals.get_mut(ident).or(self.globals.get_mut(ident))
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.ok_or(RuntimeError::VariableUndefined(ident.clone()))
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}
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fn variable_exists(&self, ident: &String) -> bool {
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self.locals.contains_key(ident) || self.globals.contains_key(ident)
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}
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pub fn exec(&mut self, tree: Box<ParseTree>) -> Result<Value, RuntimeError> {
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match *tree {
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ParseTree::Add(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x + y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x + y as f64)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float(x as f64 + y)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x + y)),
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(Value::String(x), Value::String(y)) => Ok(Value::String(format!("{x}{y}"))),
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(Value::Array(xtype, x), Value::Array(ytype, y)) => {
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if xtype != ytype {
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return Err(RuntimeError::TypeError(xtype, ytype));
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}
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Ok(Value::Array(xtype, [x, y].concat()))
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},
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(Value::Array(t, x), y) => {
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let ytype = y.get_type();
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if t != ytype {
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return Err(RuntimeError::TypeError(t, ytype));
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}
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// NOTE: use y's type instead of the arrays type.
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// an `empty` array has Any type, but any value will have a fixed type.
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// this converts the empty array into a typed array.
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Ok(Value::Array(ytype, [x, vec![y]].concat()))
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},
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(x, Value::Array(t, y)) => {
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let xtype = x.get_type();
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if t != xtype {
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return Err(RuntimeError::TypeError(t, xtype));
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}
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// NOTE: read above
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Ok(Value::Array(xtype, [vec![x], y].concat()))
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},
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(x, y) => Err(RuntimeError::NoOverloadForTypes("+".into(), vec![x, y]))
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},
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ParseTree::Sub(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x - y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x - y as f64)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float(x as f64 - y)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x - y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("-".into(), vec![x, y]))
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},
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ParseTree::Mul(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x * y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x * y as f64)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float(x as f64 * y)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x * y)),
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(Value::String(x), Value::Int(y)) => Ok(Value::String(x.repeat(y as usize))),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("*".into(), vec![x, y]))
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},
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ParseTree::Div(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x / y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x / y as f64)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float(x as f64 / y)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x / y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("*".into(), vec![x, y]))
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},
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ParseTree::Exp(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x.pow(y as u32))),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float((x as f64).powf(y))),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x.powf(y as f64))),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x.powf(y))),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("**".into(), vec![x, y])),
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},
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ParseTree::Mod(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Int(x % y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Float(x % y as f64)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Float(x as f64 % y)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Float(x % y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("%".into(), vec![x, y])),
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},
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ParseTree::EqualTo(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x == y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool(x as f64 == y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x == y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x == y)),
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(Value::Bool(x), Value::Bool(y)) => Ok(Value::Bool(x == y)),
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(Value::String(x), Value::String(y)) => Ok(Value::Bool(x == y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("==".into(), vec![x, y])),
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},
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ParseTree::NotEqualTo(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x != y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool(x as f64 != y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x != y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x != y)),
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(Value::Bool(x), Value::Bool(y)) => Ok(Value::Bool(x != y)),
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(Value::String(x), Value::String(y)) => Ok(Value::Bool(x != y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("!=".into(), vec![x, y])),
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},
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ParseTree::GreaterThan(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x > y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool(x as f64 > y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x > y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x > y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes(">".into(), vec![x, y])),
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},
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ParseTree::GreaterThanOrEqualTo(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x >= y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool(x as f64 >= y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x >= y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x >= y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes(">=".into(), vec![x, y])),
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},
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ParseTree::LessThan(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x < y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool((x as f64) < y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x < y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x < y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("<".into(), vec![x, y])),
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},
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ParseTree::LessThanOrEqualTo(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Int(x), Value::Int(y)) => Ok(Value::Bool(x <= y)),
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(Value::Int(x), Value::Float(y)) => Ok(Value::Bool(x as f64 <= y)),
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(Value::Float(x), Value::Int(y)) => Ok(Value::Bool(x <= y as f64)),
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(Value::Float(x), Value::Float(y)) => Ok(Value::Bool(x <= y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("<=".into(), vec![x, y])),
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},
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ParseTree::Not(x) => match self.exec(x)? {
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Value::Bool(x) => Ok(Value::Bool(!x)),
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x => Err(RuntimeError::NoOverloadForTypes("not".into(), vec![x]))
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},
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ParseTree::And(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Bool(x), Value::Bool(y)) => Ok(Value::Bool(x && y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("&&".into(), vec![x, y]))
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},
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ParseTree::Or(x, y) => match (self.exec(x)?, self.exec(y)?) {
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(Value::Bool(x), Value::Bool(y)) => Ok(Value::Bool(x || y)),
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(x, y) => Err(RuntimeError::NoOverloadForTypes("||".into(), vec![x, y]))
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},
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ParseTree::Equ(ident, body, scope) => {
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if self.variable_exists(&ident) {
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Err(RuntimeError::ImmutableError(ident.clone()))
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} else {
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let value = self.exec(body)?;
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let g = self.globals.clone();
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Executor::new(self.exprs, &mut self.globals)
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.locals(self.locals.clone())
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.add_local(ident, Arc::new(RefCell::new(Object::value(value, g, self.locals.to_owned()))))
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.exec(scope)
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}
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},
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ParseTree::LazyEqu(ident, body, scope) => {
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if self.variable_exists(&ident) {
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Err(RuntimeError::ImmutableError(ident.clone()))
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} else {
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let g = self.globals.clone();
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Executor::new(self.exprs, &mut self.globals)
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.locals(self.locals.clone())
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.add_local(ident, Arc::new(RefCell::new(Object::variable(*body, g, self.locals.to_owned()))))
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.exec(scope)
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}
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},
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ParseTree::FunctionDefinition(func, scope) => {
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let g = self.globals.clone();
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Executor::new(self.exprs, &mut self.globals)
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.locals(self.locals.clone())
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.add_local(func.name().unwrap().to_string(), Arc::new(RefCell::new(Object::function(func, g, self.locals.clone()))))
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.exec(scope)
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},
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ParseTree::Compose(x, y) => {
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self.exec(x)?;
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self.exec(y)
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},
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ParseTree::Id(x) => self.exec(x),
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ParseTree::If(cond, body) => if match self.exec(cond)? {
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Value::Float(f) => f != 0.0,
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Value::Int(i) => i != 0,
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Value::Bool(b) => b,
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Value::String(s) => !s.is_empty(),
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Value::Array(_, vec) => !vec.is_empty(),
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Value::Nil => false,
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x => return Err(RuntimeError::NoOverloadForTypes("?".into(), vec![x])),
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} {
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self.exec(body)
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} else {
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Ok(Value::Nil)
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},
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ParseTree::IfElse(cond, istrue, isfalse) => if match self.exec(cond)? {
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Value::Float(f) => f != 0.0,
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Value::Int(i) => i != 0,
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Value::Bool(b) => b,
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Value::String(s) => !s.is_empty(),
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Value::Array(_, vec) => !vec.is_empty(),
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Value::Nil => false,
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x => return Err(RuntimeError::NoOverloadForTypes("??".into(), vec![x])),
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} {
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self.exec(istrue)
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} else {
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self.exec(isfalse)
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},
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ParseTree::FunctionCall(ident, args) => {
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let args = args.into_iter().map(|x| Object::variable(x, self.globals.clone(), self.locals.clone())).collect();
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let obj = self.get_object_mut(&ident)?;
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let v = obj.borrow_mut().eval()?;
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match v {
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Value::Function(mut f) => f.call(obj.borrow().globals(), obj.borrow().locals(), args),
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_ => Err(RuntimeError::FunctionUndefined(ident.clone()))
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}
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},
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ParseTree::Variable(ident) => {
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let obj = self.get_object_mut(&ident)?;
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let v = obj.borrow_mut().eval()?;
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Ok(v)
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},
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ParseTree::Constant(value) => Ok(value),
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ParseTree::IntCast(x) => match self.exec(x)? {
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Value::Int(x) => Ok(Value::Int(x)),
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Value::Float(x) => Ok(Value::Int(x as i64)),
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Value::Bool(x) => Ok(Value::Int(if x { 1 } else { 0 })),
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Value::String(x) => {
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let r: i64 = x.parse().map_err(|_| RuntimeError::ParseFail(x.clone(), Type::Int))?;
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Ok(Value::Int(r))
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}
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x => Err(RuntimeError::NoOverloadForTypes("int".into(), vec![x])),
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},
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ParseTree::FloatCast(x) => match self.exec(x)? {
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Value::Int(x) => Ok(Value::Float(x as f64)),
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Value::Float(x) => Ok(Value::Float(x)),
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Value::Bool(x) => Ok(Value::Float(if x { 1.0 } else { 0.0 })),
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Value::String(x) => {
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let r: f64 = x.parse().map_err(|_| RuntimeError::ParseFail(x.clone(), Type::Int))?;
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Ok(Value::Float(r))
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}
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x => Err(RuntimeError::NoOverloadForTypes("float".into(), vec![x])),
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},
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ParseTree::BoolCast(x) => match self.exec(x)? {
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Value::Int(x) => Ok(Value::Bool(x != 0)),
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Value::Float(x) => Ok(Value::Bool(x != 0.0)),
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Value::Bool(x) => Ok(Value::Bool(x)),
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Value::String(x) => Ok(Value::Bool(!x.is_empty())),
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Value::Array(_, vec) => Ok(Value::Bool(!vec.is_empty())),
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x => Err(RuntimeError::NoOverloadForTypes("bool".into(), vec![x])),
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},
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ParseTree::StringCast(x) => Ok(Value::String(format!("{}", self.exec(x)?))),
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ParseTree::Print(x) => match self.exec(x)? {
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Value::String(s) => {
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println!("{s}");
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Ok(Value::Nil)
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}
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x => {
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println!("{x}");
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Ok(Value::Nil)
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}
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}
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ParseTree::LambdaDefinition(func) => Ok(Value::Function(func)),
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ParseTree::NonCall(name) => {
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let obj = self.get_object_mut(&name)?;
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let v = obj.borrow_mut().eval()?;
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Ok(v)
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}
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ParseTree::Head(x) => match self.exec(x)? {
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Value::Array(_, x) => Ok(x.first().ok_or(RuntimeError::EmptyArray)?.clone()),
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t => Err(RuntimeError::NoOverloadForTypes("head".into(), vec![t]))
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},
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ParseTree::Tail(x) => match self.exec(x)? {
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Value::Array(t, x) => Ok(Value::Array(t, if x.len() > 0 { x[1..].to_vec() } else { vec![] })),
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t => Err(RuntimeError::NoOverloadForTypes("tail".into(), vec![t]))
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},
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ParseTree::Init(x) => match self.exec(x)? {
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Value::Array(t, x) => Ok(Value::Array(t, if x.len() > 0 { x[..x.len() - 1].to_vec() } else { vec![] })),
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t => Err(RuntimeError::NoOverloadForTypes("init".into(), vec![t]))
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},
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ParseTree::Fini(x) => match self.exec(x)? {
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Value::Array(_, x) => Ok(x.last().ok_or(RuntimeError::EmptyArray)?.clone()),
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t => Err(RuntimeError::NoOverloadForTypes("fini".into(), vec![t]))
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},
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ParseTree::Nop => Ok(Value::Nil),
|
|
ParseTree::Export(names) => {
|
|
for name in names {
|
|
let obj = self.locals.remove(&name).ok_or(RuntimeError::VariableUndefined(name.clone()))?;
|
|
self.globals.insert(name, obj);
|
|
}
|
|
|
|
Ok(Value::Nil)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, I: Iterator<Item = Result<ParseTree, ParseError>>> Iterator for Executor<'a, I> {
|
|
type Item = Result<Value, RuntimeError>;
|
|
|
|
fn next(&mut self) -> Option<Self::Item> {
|
|
let expr = self.exprs.next();
|
|
|
|
match expr {
|
|
Some(Ok(expr)) => Some(self.exec(Box::new(expr))),
|
|
Some(Err(e)) => Some(Err(RuntimeError::ParseError(e))),
|
|
None => None,
|
|
}
|
|
}
|
|
} |