AstroLang/src/parser.rs

use crate::lexer::{Token, TokenType};

#[derive(Debug)]
pub enum ASTPart {
    String(AstString),
    Number(AstNumber),
    Assigment(AstAssigment),
    Operation(AstOperation),
    VarRead(AstVarRead),
    Call(AstCall),
    NOOP
}
#[derive(Debug)]
pub struct AstString {
    pub value: String,
    pub pos: usize
}
#[derive(Debug)]
pub struct AstNumber {
    pub value: i64,
    pub pos: usize
}
#[derive(Debug)]
pub struct AstAssigment {
    pub variable: String,
    pub value: Box<ASTPart>,
    pub pos: usize
}
#[derive(Debug)]
pub struct AstOperation {
    pub operator: String,
    pub left: Box<ASTPart>,
    pub right: Box<ASTPart>,
    pub pos: usize
}
#[derive(Debug)]
pub struct AstVarRead {
    pub variable: String,
    pub pos: usize
}
#[derive(Debug)]
pub struct AstCall {
    pub function: Box<ASTPart>,
    pub args: Vec<ASTPart>,
    pub pos: usize
}

fn is_end(input: &Token, end: &Vec<Token>) -> bool {
    for token in end {
        if input.typ == token.typ && (token.value == "" || input.value == token.value) {
            return true;
        }
    }
    return false;
}

fn read_call(variable: ASTPart, pos: &mut usize, input: &Vec<Token>) -> ASTPart {
    let mut args: Vec<ASTPart> = vec![];
    *pos += 1;
    let start_pos = *pos;
    while pos < &mut input.len() {
        let token = &input[*pos];
        if token.typ == TokenType::SEPARATOR && token.value == "," {
            *pos += 1;
            continue;            
        }
        if token.typ == TokenType::SEPARATOR && token.value == String::from(")") {
            *pos += 1;
            break;
        }
        let ends: Vec<Token> = vec![
            Token { typ: TokenType::SEPARATOR, value: String::from(","), pos: 0 },
            Token { typ: TokenType::SEPARATOR, value: String::from(")"), pos: 0 }
        ];
        let arg = read_exp(pos, input, &ends, &ends);
        args.push(arg);
    }
    return ASTPart::Call(AstCall { function: Box::new(variable), args: args, pos: start_pos });
}

fn shunt(input: Vec<ASTPart>) -> ASTPart {
    for part in input {
        
    }
    return ASTPart::NOOP;
}
fn read_exp(pos: &mut usize, input: &Vec<Token>, ends: &Vec<Token>, parse_ends: &Vec<Token>) -> ASTPart {
    let mut expressions: Vec<ASTPart> = vec![];
    while pos < &mut input.len() {
        let token = &input[*pos];
        let mut next_token = &Token {
            typ: TokenType::OPEND,
            value: String::from("END"),
            pos: 0
        };
        if *pos+1 < input.len() {
            next_token = &input[*pos+1]
        }
        if is_end(token, &parse_ends) {
            break;
        }
        *pos += 1;
        if is_end(token, ends) {
            break;
        }
        if token.typ == TokenType::STRING {
            expressions.push(ASTPart::String(AstString { value: token.value.clone(), pos: token.pos }));
        } else if token.typ == TokenType::NUMBER {
            expressions.push(ASTPart::Number(AstNumber { value: token.value.parse().unwrap(), pos: token.pos }));
        } else if token.typ == TokenType::IDENTIFIER {
            if next_token.typ == TokenType::SEPARATOR && next_token.value == "(" {
                let var = ASTPart::VarRead(AstVarRead { variable: token.value.clone(), pos: token.pos });
                expressions.push(read_call(var, pos, input));
            } else {
                expressions.push(ASTPart::VarRead(AstVarRead { variable: token.value.clone(), pos: token.pos }));
            }
        } else if token.typ == TokenType::OPERATOR {
            expressions.push(ASTPart::Operation(AstOperation { operator: token.value.clone(), left: Box::new(ASTPart::NOOP), right: Box::new(ASTPart::NOOP), pos: token.pos }));
        } else {
            panic!("Unexpected {:?}({}) at {}", token.typ, token.value, token.pos);
        }
    }
    println!("{:?}", expressions);
    let shunted = shunt(expressions);
    return ASTPart::NOOP;
}

fn next_operation(pos: &mut usize, input: &Vec<Token>, op_ends: &Vec<Token>, parse_ends: &Vec<Token>) -> ASTPart {
    let token = &input[*pos];
    if is_end(token, &parse_ends) {
        return ASTPart::NOOP;
    }
    *pos += 1;
    if is_end(token, &op_ends) {
        return ASTPart::NOOP;
    }
    if token.typ == TokenType::KEYWORD {
        if token.value == "gethelj" {
            let variable = &input[*pos];
            *pos += 1;
            if variable.typ != TokenType::IDENTIFIER {
                panic!("Unexpected {:?} at {}", variable.typ, variable.pos)
            }
            let eq = &input[*pos];
            if eq.typ == TokenType::SEPARATOR && eq.value == "=" {
                *pos += 1;
            }
            let value = read_exp(pos, input, op_ends, parse_ends);
            return ASTPart::Assigment(AstAssigment { variable: variable.value.clone(), value: Box::new(value), pos: token.pos });
        } else {
            panic!("Unexpected {:?}({}) at {}", token.typ, token.value, token.pos);
        }
    } else {
        panic!("Unexpected {:?}({}) at {}", token.typ, token.value, token.pos);
    }
}

fn parse_internal(input: Vec<Token>, op_ends: Vec<Token>, parse_ends: Vec<Token>) -> Vec<ASTPart> {
    let mut out: Vec<ASTPart> = vec![];
    let mut pos = 0;
    while pos < input.len() {
        let op = next_operation(&mut pos, &input, &op_ends, &parse_ends);
        match op {
            ASTPart::NOOP => {},
            _ => {
                out.push(op);
            }
        }
        if is_end(&input[pos], &parse_ends) {
            break;
        }
    }
    return out;
}
pub fn parse(input: Vec<Token>) -> Vec<ASTPart> {
    let op_ends: Vec<Token> = vec![
        Token { typ: TokenType::OPEND, value: String::from("\n"), pos: 0 },
        Token { typ: TokenType::OPEND, value: String::from(";"), pos: 0 },
        Token { typ: TokenType::OPEND, value: String::from("EOF"), pos: 0 }
    ];
    let parse_ends: Vec<Token> = vec![
        Token { typ: TokenType::OPEND, value: String::from("EOF"), pos: 0 }
    ];
    let out = parse_internal(input, op_ends, parse_ends);
    return out;
}