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|
use nom::{
IResult,
Parser,
branch::alt,
multi::many0,
bytes::complete::{tag, take_while1},
character::complete::multispace1,
};
#[derive(Debug,PartialEq)]
pub enum Token {
ParOpen,
ParClose,
Num(i32),
Sym(String),
Whitespace(String),
}
use Token::*;
use crate::parse::util::*;
fn parse_token(s: &str) -> IResult<&str, Token> {
alt((
tag("(").map(|_| ParOpen),
tag(")").map(|_| ParClose),
multispace1.map(whitespace),
nom::character::complete::i32.map(Num),
take_while1(|c| !(" \n\t()".contains(c))).map(sym),
)).parse(s)
}
fn tokenize(s: &str) -> Result<Vec<Token>, String> {
match many0(parse_token).parse(s) {
Ok(("", res)) => Ok(res),
Ok((rest, _)) => Err(format!("all data should be tokenizable, '{rest}' was not")),
Err(e) => Err(e.to_string()),
}
}
#[cfg(test)]
mod private_parsing_tests {
use super::{*, parse_token};
#[test]
fn test_parse_token() {
assert_eq!(parse_token("()"), Ok((")", ParOpen)));
assert_eq!(parse_token(")"), Ok(("", ParClose)));
assert_eq!(parse_token(" \t\n"), Ok(("", whitespace(" \t\n"))));
assert_eq!(parse_token("1 23"), Ok((" 23", Num(1))));
assert_eq!(parse_token("23"), Ok(("", Num(23))));
assert_eq!(parse_token("Nil a"), Ok((" a", sym("Nil"))));
assert_eq!(parse_token("a"), Ok(("", sym("a"))));
assert!(parse_token("").is_err())
}
#[test]
fn test_tokenize() {
assert_eq!(
tokenize("(+ 1 2 (\t\n a)").unwrap(),
vec![
ParOpen,
sym("+"), whitespace(" "),
Num(1), whitespace(" "),
Num(2), whitespace(" "),
ParOpen, whitespace("\t\n "),
sym("a"),
ParClose
]
);
}
}
|
