| use nom::branch::alt; |
| use nom::bytes::complete::tag; |
| use nom::character::streaming::digit1 as digit; |
| use nom::combinator::{map, map_res, opt, recognize}; |
| use nom::sequence::{delimited, pair}; |
| use nom::IResult; |
| |
| use std::str; |
| use std::str::FromStr; |
| |
| fn unsigned_float(i: &[u8]) -> IResult<&[u8], f32> { |
| let float_bytes = recognize(alt(( |
| delimited(digit, tag("."), opt(digit)), |
| delimited(opt(digit), tag("."), digit), |
| ))); |
| let float_str = map_res(float_bytes, str::from_utf8); |
| map_res(float_str, FromStr::from_str)(i) |
| } |
| |
| fn float(i: &[u8]) -> IResult<&[u8], f32> { |
| map( |
| pair(opt(alt((tag("+"), tag("-")))), unsigned_float), |
| |(sign, value)| { |
| sign |
| .and_then(|s| if s[0] == b'-' { Some(-1f32) } else { None }) |
| .unwrap_or(1f32) |
| * value |
| }, |
| )(i) |
| } |
| |
| #[test] |
| fn unsigned_float_test() { |
| assert_eq!(unsigned_float(&b"123.456;"[..]), Ok((&b";"[..], 123.456))); |
| assert_eq!(unsigned_float(&b"0.123;"[..]), Ok((&b";"[..], 0.123))); |
| assert_eq!(unsigned_float(&b"123.0;"[..]), Ok((&b";"[..], 123.0))); |
| assert_eq!(unsigned_float(&b"123.;"[..]), Ok((&b";"[..], 123.0))); |
| assert_eq!(unsigned_float(&b".123;"[..]), Ok((&b";"[..], 0.123))); |
| } |
| |
| #[test] |
| fn float_test() { |
| assert_eq!(float(&b"123.456;"[..]), Ok((&b";"[..], 123.456))); |
| assert_eq!(float(&b"+123.456;"[..]), Ok((&b";"[..], 123.456))); |
| assert_eq!(float(&b"-123.456;"[..]), Ok((&b";"[..], -123.456))); |
| } |
