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#[macro_export]
macro_rules! npn {
[() -> ()] => {};
[() -> ($stack:tt)] => {$stack};
[(+ $($tail:tt)*) -> ($($stack:tt)*)] => { npn!(($($tail)*) -> (+ $($stack)*)) };
[(- $($tail:tt)*) -> ($($stack:tt)*)] => { npn!(($($tail)*) -> (- $($stack)*)) };
[(* $($tail:tt)*) -> ($($stack:tt)*)] => { npn!(($($tail)*) -> (* $($stack)*)) };
[(/ $($tail:tt)*) -> ($($stack:tt)*)] => { npn!(($($tail)*) -> (/ $($stack)*)) };
[($head:tt $($tail:tt)*) -> (+ $($stack:tt)*)] => { npn!(($($tail)*) -> ($head + $($stack)*)) };
[($head:tt $($tail:tt)*) -> (- $($stack:tt)*)] => { npn!(($($tail)*) -> ($head - $($stack)*)) };
[($head:tt $($tail:tt)*) -> (* $($stack:tt)*)] => { npn!(($($tail)*) -> ($head * $($stack)*)) };
[($head:tt $($tail:tt)*) -> (/ $($stack:tt)*)] => { npn!(($($tail)*) -> ($head / $($stack)*)) };
[($head:tt $($tail:tt)*) -> ($stack_head:tt + $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_head + $head) $($stack)*)) };
[($head:tt $($tail:tt)*) -> ($stack_head:tt - $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_head - $head) $($stack)*)) };
[($head:tt $($tail:tt)*) -> ($stack_head:tt * $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_head * $head) $($stack)*)) };
[($head:tt $($tail:tt)*) -> ($stack_head:tt / $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_head / $head) $($stack)*)) };
[($($tail:tt)*) -> ($stack_first:tt $stack_second:tt + $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_second + $stack_first) $($stack)*)) };
[($($tail:tt)*) -> ($stack_first:tt $stack_second:tt - $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_second - $stack_first) $($stack)*)) };
[($($tail:tt)*) -> ($stack_first:tt $stack_second:tt * $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_second * $stack_first) $($stack)*)) };
[($($tail:tt)*) -> ($stack_first:tt $stack_second:tt / $($stack:tt)*)] => { npn!(($($tail)*) -> (($stack_second / $stack_first) $($stack)*)) };
[$first:tt $second:tt $($tail:tt)*] => { npn!(($($tail)*) -> ($second $first)) };
}
#[cfg(test)]
mod npn_tests {
#[test]
fn basic_add() { assert_eq!(npn!(+ 1 2), 3); }
#[test]
fn double_add() { assert_eq!(npn!(+ + 1 2 3), 6); }
#[test]
fn lots_of_add() {
assert_eq!(npn!(+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32), 528);
}
#[test]
fn basic_subtract() { assert_eq!(npn!(- 1 2), -1); }
#[test]
fn double_subtract() { assert_eq!(npn!(- - 5 2 4), -1); }
#[test]
fn subtract_and_add() { assert_eq!(npn!(- + 1 2 3), 0); }
#[test]
fn add_and_subtract() { assert_eq!(npn!(+ - 1 2 3), 2); }
#[test]
fn adds_and_subtracts() { assert_eq!(npn!(+ - - + 1 2 - 3 + 4 5 6 7), 10); }
#[test]
fn basic_multiply() { assert_eq!(npn!(* 3 2), 6); }
#[test]
fn double_multiply() { assert_eq!(npn!(* 3 * 2 3), 18); }
#[test]
fn adds_substracts_and_multiplies_oh_my() { assert_eq!(npn!(* - - * * + + * * * 2 3 2 3 2 3 2 3 2 3 2), 482); }
#[test]
fn basic_divide() { assert_eq!(npn!(/ 8 4), 2); }
#[test]
fn double_divide() { assert_eq!(npn!(/ 24 / 12 4), 8); }
#[test]
fn all_division_pairs() {
assert_eq!(npn!(/ + / - / * / / + - / * / 128 2 4 2 64 192 4 2 4 2 32 2 16 8), 4);
}
#[test]
fn wikipedia_tests() {
assert_eq!(npn!(* - 5 6 7), -7);
assert_eq!(npn!(- * / 15 - 7 + 1 1 3 + 2 + 1 1), 5);
}
#[test]
fn test_with_non_numbers() {
let foo = 3;
let bar = 12;
assert_eq!(npn!(/ bar foo), 4);
fn baz() -> i64 { 2 }
assert_eq!(npn!(/ bar (baz())), 6);
assert_eq!(npn!(+ foo (-3)), 0);
}
}
#[macro_export]
macro_rules! rpn {
[() -> ()] => {};
[() -> ($stack:tt)] => {$stack};
[(+ $($tail:tt)*) -> ($stack_first:tt $stack_second:tt $($stack:tt)*)] => { rpn!(($($tail)*) -> (($stack_second + $stack_first) $($stack)*)) };
[(- $($tail:tt)*) -> ($stack_first:tt $stack_second:tt $($stack:tt)*)] => { rpn!(($($tail)*) -> (($stack_second - $stack_first) $($stack)*)) };
[(* $($tail:tt)*) -> ($stack_first:tt $stack_second:tt $($stack:tt)*)] => { rpn!(($($tail)*) -> (($stack_second * $stack_first) $($stack)*)) };
[(/ $($tail:tt)*) -> ($stack_first:tt $stack_second:tt $($stack:tt)*)] => { rpn!(($($tail)*) -> (($stack_second / $stack_first) $($stack)*)) };
[($head:tt $($tail:tt)*) -> ($($stack:tt)*)] => { rpn!(($($tail)*) -> ($head $($stack)*)) };
[$first:tt $second:tt $($tail:tt)*] => { rpn!(($($tail)*) -> ($second $first)) };
}
#[cfg(test)]
mod rpn_tests {
#[test]
fn basic_add() { assert_eq!(rpn!(1 2 +), 3); }
#[test]
fn double_add() { assert_eq!(rpn!(1 2 + 3 +), 6); }
#[test]
fn basic_subtract() { assert_eq!(rpn!(1 2 -), -1); }
#[test]
fn double_subtract() { assert_eq!(rpn!(5 2 - 4 -), -1); }
#[test]
fn basic_multiply() { assert_eq!(rpn!(3 2 *), 6); }
#[test]
fn double_multiply() { assert_eq!(rpn!(3 2 * 3 *), 18); }
#[test]
fn basic_divide() { assert_eq!(rpn!(8 4 /), 2); }
#[test]
fn double_divide() { assert_eq!(rpn!(24 12 4 / /), 8); }
#[test]
fn all_operators() {
assert_eq!(rpn!(2 3 + 5 * 15 - 5 /), 2);
}
#[test]
fn wikipedia_tests() {
assert_eq!(rpn!(15 7 1 1 + - / 3 * 2 1 1 + + -), 5);
}
#[test]
fn test_with_non_numbers() {
let foo = 3;
let bar = 12;
assert_eq!(rpn!(bar foo /), 4);
fn baz() -> i64 { 2 }
assert_eq!(rpn!(bar (baz()) /), 6);
assert_eq!(rpn!(foo (-3) +), 0);
}
}