sscanf 0.5.0

A sscanf (inverse of format!()) macro with near unlimited parsing capabilities
Documentation
use sscanf::{advanced::AcceptsRegexOverride, *};

static CORRECT_INPUT: &str = "Testing with (3.4,1,-2,0)!";
macro_rules! correct_result {
    (named) => {
        TestStruct {
            a: 0,
            b: String::from("1"),
            c: -2,
            d: 3.4,
        }
    };
    (unnamed) => {
        TestStruct(0, String::from("1"), -2, 3.4)
    };
}

static WRONG_INPUTS: &[&str] = &[
    "Testing with (3.4,1,-2)!",
    "Testing with (3.-4,1,-2,0)!",
    "Testing with (3.4,,-2,0)!",
    "Testing with (3.4,1,,0)!",
    "Testing with (3.4,1,+-2,0)!",
    "Testing with (3.4,1,-2,1000)!",
];

#[test]
#[allow(clippy::vec_init_then_push)]
fn defaults() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({d},{b},{c},{a})")]
    struct TestStruct {
        a: u8,
        b: String,
        #[sscanf(default)]
        e: Vec<usize>,
        #[sscanf(default = vec![5])]
        f: Vec<usize>,
        #[sscanf(default = outer_source())]
        g: Vec<usize>,
        #[sscanf(default = {
            let mut v = Vec::new();
            v.push(0);
            for _ in 0..7 {
                *v.last_mut().unwrap() +=1;
            }
            v
        })]
        h: Vec<usize>,
        c: isize,
        d: f32,
    }

    fn outer_source() -> Vec<usize> {
        vec![6]
    }

    let correct = TestStruct {
        a: 0,
        b: String::from("1"),
        c: -2,
        d: 3.4,
        e: Default::default(),
        f: vec![5],
        g: vec![6],
        h: vec![7],
    };

    let ret = sscanf!(CORRECT_INPUT, "Testing with {TestStruct}!").unwrap();
    assert_eq!(ret, correct);

    for input in WRONG_INPUTS {
        assert!(sscanf!(input, "Testing with {TestStruct}!").is_none());
    }
}

#[test]
fn mapper() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({d},{b},{c},{a})")]
    struct TestStruct {
        #[sscanf(map = |x: char| x.to_digit(10).unwrap() as u8)]
        a: u8,
        #[sscanf(map = |x: usize| x.to_string())]
        b: String,
        #[sscanf(map = |x: i8| x as isize)]
        c: isize,
        d: f32,
    }

    let ret = sscanf!(CORRECT_INPUT, "Testing with {TestStruct}!").unwrap();
    assert_eq!(ret, correct_result!(named));

    for input in WRONG_INPUTS {
        assert!(sscanf!(input, "Testing with {TestStruct}!").is_none());
    }
}

#[test]
fn filter_mapper() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({d},{b},{c},{a})")]
    struct TestStruct {
        #[sscanf(filter_map = |x: char| x.to_digit(10).map(|x| x as u8))]
        a: u8,
        #[sscanf(filter_map = |x: usize| if x == 1 { Some(x.to_string()) } else { None })]
        b: String,
        #[sscanf(filter_map = |x: i8| if x < 0 { Some(x as isize) } else { None })]
        c: isize,
        d: f32,
    }

    let input = "Testing with (3.4,1,-2,0)!";
    let ret = sscanf!(input, "Testing with {TestStruct}!").unwrap();
    assert_eq!(ret, correct_result!(named));

    for input in [
        "Testing with (3.4,1,-2,a)!", // a is not a digit
        "Testing with (3.4,2,-2,0)!", // b != 1
        "Testing with (3.4,1,2,0)!",  // c is not negative
    ] {
        assert!(sscanf!(input, "Testing with {TestStruct}!").is_none());
    }

    for input in WRONG_INPUTS {
        assert!(sscanf!(input, "Testing with {TestStruct}!").is_none());
    }
}

#[test]
fn from() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({d},{b},{c},{a})")]
    struct TestStruct {
        #[sscanf(try_from = i64)]
        a: u8,
        #[sscanf(from = &str)]
        b: String,
        #[sscanf(from = i8)]
        c: isize,
        d: f32,
    }

    let ret = sscanf!(CORRECT_INPUT, "Testing with {TestStruct}!").unwrap();
    assert_eq!(ret, correct_result!(named));

    for input in WRONG_INPUTS {
        assert!(sscanf!(input, "Testing with {TestStruct}!").is_none());
    }
}

#[test]
fn lifetimes() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({name},{age},{address})")]
    struct Person<'a, 'b> {
        name: &'a str,
        age: u8,
        address: &'b str,
        #[sscanf(default = "")]
        source: &'static str,
    }

    let input = String::from("Hi, I'm (Bob,42,here)!");
    let bob = sscanf!(input, "Hi, I'm {Person}!").unwrap();

    assert_eq!(bob.name, "Bob");
    assert_eq!(bob.age, 42);
    assert_eq!(bob.address, "here");
}

#[test]
fn lifetimes_mapped() {
    #[derive(Debug, PartialEq)]
    struct StrCutter<'a>(&'a str, &'a str);

    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({name},{age},{address})")]
    struct Person<'a, 'b> {
        name: &'a str,
        age: u8,
        #[sscanf(map = |x: &'b str| StrCutter(&x[..2], &x[2..]))]
        address: StrCutter<'b>,
        #[sscanf(default = "")]
        source: &'static str,
    }

    let input = String::from("Hi, I'm (Bob,42,here)!");
    let bob = sscanf!(input, "Hi, I'm {Person}!").unwrap();

    assert_eq!(bob.name, "Bob");
    assert_eq!(bob.age, 42);
    assert_eq!(bob.address, StrCutter("he", "re"));
}

#[test]
fn lifetime_static() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({name},{age},{address})")]
    struct Person {
        name: &'static str,
        age: u8,
        address: &'static str,
    }

    let input = "Hi, I'm (Bob,42,here)!";
    let bob = sscanf!(input, "Hi, I'm {Person}!").unwrap();

    assert_eq!(bob.name, "Bob");
    assert_eq!(bob.age, 42);
    assert_eq!(bob.address, "here");
}

#[test]
fn generic_from_scanf() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({name},{age},{data:/[a-z]+/})")]
    struct Person<T = usize>
    where
        T: for<'a> FromScanf<'a> + for<'a> AcceptsRegexOverride<'a>,
    {
        name: String,
        age: u8,
        data: T,
    }

    let input = "Hi, I'm (Bob,42,here)!";
    let bob = sscanf!(input, "Hi, I'm {Person<String>}!").unwrap();

    assert_eq!(bob.name, "Bob");
    assert_eq!(bob.age, 42);
    assert_eq!(bob.data, "here");
}

#[test]
fn generic_default() {
    #[derive(FromScanf, Debug, PartialEq)]
    #[sscanf(format = "({name},{age})")]
    struct Person<T: Default> {
        name: String,
        age: u8,
        #[sscanf(default)]
        data: T,
    }

    let input = "Hi, I'm (Bob,42)!";
    let bob = sscanf!(input, "Hi, I'm {Person<String>}!").unwrap();

    assert_eq!(bob.name, "Bob");
    assert_eq!(bob.age, 42);
    assert_eq!(bob.data, "");
}