Last active
October 20, 2022 19:10
-
-
Save jtlapp/41922c2bd81e76e74a4b174e713e4617 to your computer and use it in GitHub Desktop.
all working but alloc_attack
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// thanks to assistance from Martin Kavik and discord/rust @kpreid | |
use std::collections::HashMap; | |
pub type Value = i32; | |
pub type Result = std::result::Result<(), Error>; | |
#[derive(Debug, PartialEq, Eq)] | |
pub enum Error { | |
DivisionByZero, | |
StackUnderflow, | |
UnknownWord, | |
InvalidWord, | |
} | |
enum Operation { | |
BuiltIn(fn(&mut Stack) -> Result), | |
Custom(Vec<Token>), | |
} | |
type Stack = Vec<Value>; | |
#[derive(PartialEq, Clone)] | |
enum Token { | |
Colon, | |
Semicolon, | |
Value(Value), | |
Word(String), | |
} | |
impl Token { | |
fn new(token: &str) -> Self { | |
match token { | |
":" => Token::Colon, | |
";" => Token::Semicolon, | |
_ => match token.parse::<Value>() { | |
Ok(value) => Token::Value(value), | |
Err(_) => Token::Word(token.into()), | |
}, | |
} | |
} | |
} | |
pub struct Forth { | |
op_map: HashMap<String, Operation>, | |
stack: Stack, | |
} | |
impl Forth { | |
pub fn new() -> Self { | |
let forth = Self { | |
op_map: HashMap::from([ | |
("+".into(), Operation::BuiltIn(Forth::add)), | |
("-".into(), Operation::BuiltIn(Forth::subtract)), | |
("*".into(), Operation::BuiltIn(Forth::multiply)), | |
("/".into(), Operation::BuiltIn(Forth::divide)), | |
("dup".into(), Operation::BuiltIn(Forth::dup)), | |
("drop".into(), Operation::BuiltIn(Forth::drop)), | |
("swap".into(), Operation::BuiltIn(Forth::swap)), | |
("over".into(), Operation::BuiltIn(Forth::over)), | |
]), | |
stack: vec![], | |
}; | |
forth | |
} | |
pub fn stack(&self) -> &[Value] { | |
&self.stack | |
} | |
pub fn eval(&mut self, input: &str) -> Result { | |
let lowercase = input.to_lowercase(); | |
let tokens = lowercase | |
.split(' ') | |
.map(|word| Token::new(word)) | |
.collect::<Vec<Token>>(); | |
self.eval_tokens(&tokens) | |
} | |
fn eval_tokens(&mut self, tokens: &Vec<Token>) -> Result { | |
let mut i = 0; | |
while i < tokens.len() { | |
match &tokens[i] { | |
Token::Colon => i = self.parse_word_definition(tokens, i + 1)?, | |
token => { | |
i += 1; | |
match token { | |
Token::Word(word) => match self.op_map.get(word) { | |
Some(op) => match op { | |
Operation::BuiltIn(run) => Ok(run(&mut self.stack)?), | |
Operation::Custom(tokens) => Ok(self.eval_tokens(&tokens.clone())?), | |
}, | |
None => Err(Error::UnknownWord), | |
}, | |
Token::Value(value) => Ok(self.stack.push(*value)), | |
_ => Err(Error::UnknownWord), | |
}? | |
} | |
} | |
} | |
Ok(()) | |
} | |
fn add(stack: &mut Stack) -> Result { | |
let b = Self::pop(stack)?; | |
let a = Self::pop(stack)?; | |
Ok(stack.push(a + b)) | |
} | |
fn subtract(stack: &mut Stack) -> Result { | |
let b = Self::pop(stack)?; | |
let a = Self::pop(stack)?; | |
Ok(stack.push(a - b)) | |
} | |
fn multiply(stack: &mut Stack) -> Result { | |
let b = Self::pop(stack)?; | |
let a = Self::pop(stack)?; | |
Ok(stack.push(a * b)) | |
} | |
fn divide(stack: &mut Stack) -> Result { | |
let b = Self::pop(stack)?; | |
if b == 0 { | |
return Err(Error::DivisionByZero); | |
} | |
let a = Self::pop(stack)?; | |
Ok(stack.push(a / b)) | |
} | |
fn dup(stack: &mut Stack) -> Result { | |
match stack.last() { | |
Some(value) => Ok(stack.push(*value)), | |
None => Err(Error::StackUnderflow), | |
} | |
} | |
fn drop(stack: &mut Stack) -> Result { | |
Self::pop(stack)?; | |
Ok(()) | |
} | |
fn swap(stack: &mut Stack) -> Result { | |
let b = Self::pop(stack)?; | |
let a = Self::pop(stack)?; | |
stack.push(b); | |
Ok(stack.push(a)) | |
} | |
fn over(stack: &mut Stack) -> Result { | |
if stack.len() < 2 { | |
Err(Error::StackUnderflow) | |
} else { | |
Ok(stack.push(*stack.get(stack.len() - 2).unwrap())) | |
} | |
} | |
fn pop(stack: &mut Stack) -> std::result::Result<Value, Error> { | |
match stack.pop() { | |
Some(value) => Ok(value), | |
None => Err(Error::StackUnderflow), | |
} | |
} | |
fn parse_word_definition( | |
&mut self, | |
tokens: &Vec<Token>, | |
mut offset: usize, | |
) -> std::result::Result<usize, Error> { | |
if offset < tokens.len() { | |
if let Token::Word(word) = tokens[offset].clone() { | |
let mut terms: Vec<Token> = vec![]; | |
offset += 1; | |
while offset < tokens.len() { | |
let token = tokens[offset].clone(); | |
match token { | |
Token::Value(_) => terms.push(token), | |
Token::Word(word) => match self.op_map.get(&word) { | |
Some(op) => match op { | |
Operation::BuiltIn(_) => terms.push(Token::Word(word)), | |
Operation::Custom(subterms) => subterms | |
.iter() | |
.for_each(|subterm| terms.push(subterm.clone())), | |
}, | |
None => return Err(Error::UnknownWord), | |
}, | |
Token::Semicolon => { | |
self.op_map.insert(word.into(), Operation::Custom(terms)); | |
return Ok(offset + 1); | |
} | |
_ => panic!("unexpected token in word definition"), | |
} | |
offset += 1; | |
} | |
} | |
} | |
Err(Error::InvalidWord) | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment