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use nom::{
IResult,
Parser,
branch::alt,
bytes::complete::{tag, take_while},
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_while(|c| !(" \n\t()".contains(c))).map(sym),
)).parse(s)
}
#[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"))));
}
}
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