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holy_lisp_archive/src/parser.rs
2024-06-12 02:45:33 -05:00

101 lines
No EOL
2 KiB
Rust

use std::fmt;
use crate::Token;
pub enum LispValue {
Nil,
String(String),
LispFunction(String, Vec<OpCode>),
RustFunction(String, fn(Vec<LispValue>) -> LispValue),
Exp(OpCode)
}
impl fmt::Display for LispValue {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
LispValue::Nil => write!(f, "nil"),
LispValue::String(str) => write!(f, "{}", str),
LispValue::LispFunction(name, _) => write!(f, "<'{}': Lisp Function>", name),
LispValue::RustFunction(name, _) => write!(f, "<'{}': Rust Function>", name),
_ => todo!()
}
}
}
impl From<&str> for LispValue {
fn from(value: &str) -> Self {
LispValue::String(value.to_string())
}
}
impl From<String> for LispValue {
fn from(value: String) -> Self {
LispValue::String(value)
}
}
pub enum OpCode {
Call(String, Vec<LispValue>),
Exp(Vec<OpCode>)
}
// TODO: Handle failure
fn read_exp(open_paren_idx: usize, tokens: &Vec<Token>) -> Option<(Vec<Token>, usize)> /* Option<tokens, close_paren_idx> */ {
let mut tkns = Vec::new();
let mut depth = 0;
for i in open_paren_idx..tokens.len() - 1 {
match &tokens[i] {
Token::OpenParen => {
if depth != 0 {
tkns.push(Token::OpenParen);
}
depth += 1;
}
Token::CloseParen => {
depth -= 1;
if depth == 0 {
return Some((tkns, i));
}
}
token => {
tkns.push(token.clone());
}
}
}
None
}
fn parse_exp(tokens: Vec<Token>) -> Vec<OpCode> {
todo!()
}
pub fn parse(tokens: Vec<Token>) -> Vec<OpCode> {
let mut opcodes = Vec::new();
let mut current_depth = 0;
let mut seeking = false;
let mut i = 0;
while i < tokens.len() {
match &tokens[i] {
Token::OpenParen => {
let (tkns, close_paren_idx) = read_exp(i, &tokens).unwrap();
opcodes.push(OpCode::Exp(parse_exp(tkns)));
i = close_paren_idx;
}
tkn => {
panic!("Unexpected token {:?}", tkn);
}
}
i += 1;
}
// opcodes.push(OpCode::Call("print".to_string(), vec![
// LispValue::from("Hello, World!")
// ]));
opcodes
}