use crate::*;
macro_rules!is_ok_some(($exp:expr, $val:expr)=>{assert_eq!($exp, Ok(Some($val)))};);
macro_rules!is_ok_none(($exp:expr)=>{assert_eq!($exp, Ok(None))};);
macro_rules!is_err(($exp:expr)=>{assert!($exp.is_err())};
                   ($exp:expr, $err:expr)=>{assert_eq!($exp, Err($err))};);
#[test] fn test_exp () -> Result<(), DslError> {
    let e0 = DslError::Unexpected('a');
    let e1 = DslError::Unexpected('(');
    let e2 = DslError::Unexpected('b');
    let e3 = DslError::Unexpected('d');
    let check = |src: &str, key, exp, head, tail|{
        assert_eq!(src.key(),  key,  "{src}");
        assert_eq!(src.exp(),  exp,  "{src}");
        assert_eq!(src.head(), head, "{src}");
        assert_eq!(src.tail(), tail, "{src}");
    };
    check("a",             Ok(Some("a")), Err(e0), Ok(Some("a")), Ok(None));
    check("(a)",           Err(e1), Ok(Some("a")), Ok(Some("(a)")), Ok(None));
    check("a b c",         Err(e2), Err(e0), Ok(Some("a")), Ok(Some("b c")));
    check("(a b c)",       Err(e1), Ok(Some("a b c")), Ok(Some("(a b c)")), Ok(None));
    check("(a b c) d e f", Err(e1), Err(e3), Ok(Some("(a b c)")), Ok(Some("d e f")));
    check("a (b c d) e f", Err(e1), Err(e0), Ok(Some("a")), Ok(Some("(b c d) e f")));

    assert!(is_whitespace(' '));
    assert!(!is_key_start(' '));
    assert!(is_key_start('f'));

    is_ok_some!(key_seek_start("foo"),   0);
    is_ok_some!(key_seek_start("foo "),  0);
    is_ok_some!(key_seek_start(" foo "), 1);
    is_ok_some!(key_seek_length(&" foo "[1..]), 3);
    is_ok_some!(key_seek("foo"),   (0, 3));
    is_ok_some!(key_peek("foo"),   "foo");
    is_ok_some!(key_seek("foo "),  (0, 3));
    is_ok_some!(key_peek("foo "),  "foo");
    is_ok_some!(key_seek(" foo "), (1, 3));
    is_ok_some!(key_peek(" foo "), "foo");

    is_err!("(foo)".key());
    is_err!("foo".exp());

    is_ok_some!("(foo)".exp(), "foo");
    is_ok_some!("(foo)".head(), "(foo)");
    is_ok_none!("(foo)".tail());

    is_ok_some!("(foo bar baz)".exp(),  "foo bar baz");
    is_ok_some!("(foo bar baz)".head(), "(foo bar baz)");
    is_ok_none!("(foo bar baz)".tail());

    is_ok_some!("(foo bar baz)".exp().head(), "foo");
    is_ok_some!("(foo bar baz)".exp().tail(), "bar baz");
    is_ok_some!("(foo bar baz)".exp().tail().head(), "bar");
    is_ok_some!("(foo bar baz)".exp().tail().tail(), "baz");

    is_ok_none!("foo".exp());
    is_ok_some!("foo".key(),   "foo");
    is_ok_some!(" foo".key(),  "foo");
    is_ok_some!(" foo ".key(), "foo");

    assert_eq!(" foo ".head(),        Ok(Some("foo")));
    //assert_eq!(" foo ".head().head(), Ok(None));
    assert_eq!(" foo ".head().tail(), Ok(None));
    assert_eq!(" foo ".tail(),        Ok(None));
    assert_eq!(" foo ".tail().head(), Ok(None));
    assert_eq!(" foo ".tail().tail(), Ok(None));

    assert_eq!(" foo bar ".head(),        Ok(Some("foo")));
    //assert_eq!(" foo bar ".head().head(), Ok(None));
    assert_eq!(" foo bar ".head().tail(), Ok(None));
    assert_eq!(" foo bar ".tail(),        Ok(Some("bar")));
    assert_eq!(" foo bar ".tail().head(), Ok(Some("bar")));
    assert_eq!(" foo bar ".tail().tail(), Ok(None));

    assert_eq!(" (foo) ".head(),               Ok(Some("(foo)")));
    //assert_eq!(" (foo) ".head().head(),        Ok(Some("foo")));
    //assert_eq!(" (foo) ".head().head().head(), Ok(None));
    assert_eq!(" (foo) ".tail(),               Ok(None));

    assert_eq!(" (foo) (bar) ".head(),               Ok(Some("(foo)")));
    //assert_eq!(" (foo) (bar) ".head().head(),        Ok(Some("foo")));
    //assert_eq!(" (foo) (bar) ".head().head().head(), Ok(None));
    assert_eq!(" (foo) (bar) ".tail(),               Ok(Some("(bar)")));

    assert_eq!(" (foo bar baz) ".head(),               Ok(Some("(foo bar baz)")));
    assert_eq!(" (foo bar baz) ".head().head(),        Ok(Some("foo")));
    assert_eq!(" (foo bar baz) ".head().tail(),        Ok(Some("bar baz")));
    assert_eq!(" (foo bar baz) ".head().tail().head(), Ok(Some("bar")));
    assert_eq!(" (foo bar baz) ".head().tail().tail(), Ok(Some("baz")));
    Ok(())
}