Macro totems::assert_nth

macro_rules! assert_nth {
    ($collection:expr, $position:expr, value == $val:expr) => { ... };
    ($collection:expr, $position:expr, value != $val:expr) => { ... };
    ($collection:expr, $position:expr, value < $val:expr) => { ... };
    ($collection:expr, $position:expr, value <= $val:expr) => { ... };
    ($collection:expr, $position:expr, value > $val:expr) => { ... };
    ($collection:expr, $position:expr, value >= $val:expr) => { ... };
}

Asserts that the nth item in a collection has a relationship to some value.

Parameters

• &collection A reference to a collection.
• position The position in the collection (starts at 0).
• &val A reference to a value to compare to the nth item.

Dependencies

• All content must implement Debug
• &collection must implement IntoIterator.
• val must implement PartialEq for the types in collection to use == or !=.
• val must implement PartialOrd for the types in collection to use <, <=, >, >=.

Example

use totems::assert_nth;
let vec = vec![1, 3, 5, 7, 9, 11, 13, 15, 17, 19];
let x = 5;
assert_nth!(&vec, 2, value == &x); // vec[2] == x
assert_nth!(&vec, 2, value <= &x);
assert_nth!(&vec, 2, value >= &x);
assert_nth!(&vec, 2, value < &(x + 1));
assert_nth!(&vec, 2, value > &(x - 1));

Example Error Messages

thread 'collections::nth::le_correct' panicked at 'assertion failed: (collection[3] <= item)
         item: 5
collection[3]: 7
', src/collections.rs:388:9