schala/src/main.rs

140 lines
3.2 KiB
Rust

use std::io;
use std::io::Write;
use std::io::BufRead;
use std::char;
fn main() {
println!("Unnamed language 0.01");
repl();
}
#[derive(Debug)]
enum Token {
EOF,
Separator,
LParen,
RParen,
Comma,
NumLiteral(f64),
StrLiteral(String),
Identifier(String)
/* Keyword(Keyword) */ //implement in future
}
#[derive(Debug)]
enum ASTNode {
GenericNode
}
fn repl() {
let stdin = io::stdin();
let mut stdout = io::stdout();
let mut buf = String::with_capacity(20);
loop {
print!(">> ");
stdout.flush().ok();
let line = stdin.lock().read_line(&mut buf);
match line {
Ok(_) => {
if buf.is_empty() {
break;
}
let tokens = tokenize(&buf);
buf.clear();
println!("Tokens: {:?}", tokens);
let ast = parse(tokens);
println!("AST: {:?}", ast);
let eval = evaluate(&ast);
println!("{}", eval);
},
Err(err) => {
println!("Error: {}", err);
}
}
}
}
fn tokenize(input: &str) -> Vec<Token> {
let mut tokens = Vec::new();
let mut iterator = input.chars().peekable();
fn ends_identifier(c: char) -> bool {
match c {
c if char::is_whitespace(c) => true,
',' => true,
';' => true,
'(' => true,
')' => true,
_ => false
}
}
while let Some(c) = iterator.next() {
if char::is_whitespace(c) {
continue;
} else if c == '"' {
let mut buffer = String::with_capacity(20);
while let Some(x) = iterator.next() {
if x == '"' {
break;
}
buffer.push(x);
}
tokens.push(Token::StrLiteral(buffer));
} else if c == '#' {
while let Some(x) = iterator.next() {
if x == '\n' {
break;
}
}
} else if c == ';' || c == '\n' {
tokens.push(Token::Separator);
} else if c == '(' {
tokens.push(Token::LParen);
} else if c == ')' {
tokens.push(Token::RParen);
} else if c == ',' {
tokens.push(Token::Comma);
} else {
let mut buffer = String::with_capacity(20);
buffer.push(c);
while let Some(x) = iterator.peek().cloned() {
if ends_identifier(x) {
break;
}
buffer.push(iterator.next().unwrap());
}
match buffer.parse::<f64>() {
Ok(f) => tokens.push(Token::NumLiteral(f)),
_ => tokens.push(Token::Identifier(buffer))
}
}
}
tokens.push(Token::EOF);
tokens
}
fn parse(_input: Vec<Token>) -> ASTNode {
ASTNode::GenericNode
}
fn evaluate(input: &ASTNode) -> String {
return match eval_ast(input) {
ASTNode::GenericNode => "Not implemented".to_string()
};
fn eval_ast(_input: &ASTNode) -> ASTNode {
return ASTNode::GenericNode;
}
}