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Diffstat (limited to 'src/test/ui/traits/typeclasses-eq-example-static.rs')
-rw-r--r-- | src/test/ui/traits/typeclasses-eq-example-static.rs | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/src/test/ui/traits/typeclasses-eq-example-static.rs b/src/test/ui/traits/typeclasses-eq-example-static.rs new file mode 100644 index 000000000..f982ad6a0 --- /dev/null +++ b/src/test/ui/traits/typeclasses-eq-example-static.rs @@ -0,0 +1,68 @@ +// run-pass + +#![allow(non_camel_case_types)] +#![allow(non_snake_case)] +#![allow(dead_code)] + +// Example from lkuper's intern talk, August 2012 -- now with static +// methods! +use Color::{cyan, magenta, yellow, black}; +use ColorTree::{leaf, branch}; + +trait Equal { + fn isEq(a: &Self, b: &Self) -> bool; +} + +#[derive(Clone, Copy)] +enum Color { cyan, magenta, yellow, black } + +impl Equal for Color { + fn isEq(a: &Color, b: &Color) -> bool { + match (*a, *b) { + (cyan, cyan) => { true } + (magenta, magenta) => { true } + (yellow, yellow) => { true } + (black, black) => { true } + _ => { false } + } + } +} + +#[derive(Clone)] +enum ColorTree { + leaf(Color), + branch(Box<ColorTree>, Box<ColorTree>) +} + +impl Equal for ColorTree { + fn isEq(a: &ColorTree, b: &ColorTree) -> bool { + match (a, b) { + (&leaf(ref x), &leaf(ref y)) => { + Equal::isEq(&(*x).clone(), &(*y).clone()) + } + (&branch(ref l1, ref r1), &branch(ref l2, ref r2)) => { + Equal::isEq(&(**l1).clone(), &(**l2).clone()) && + Equal::isEq(&(**r1).clone(), &(**r2).clone()) + } + _ => { false } + } + } +} + +pub fn main() { + assert!(Equal::isEq(&cyan, &cyan)); + assert!(Equal::isEq(&magenta, &magenta)); + assert!(!Equal::isEq(&cyan, &yellow)); + assert!(!Equal::isEq(&magenta, &cyan)); + + assert!(Equal::isEq(&leaf(cyan), &leaf(cyan))); + assert!(!Equal::isEq(&leaf(cyan), &leaf(yellow))); + + assert!(Equal::isEq(&branch(Box::new(leaf(magenta)), Box::new(leaf(cyan))), + &branch(Box::new(leaf(magenta)), Box::new(leaf(cyan))))); + + assert!(!Equal::isEq(&branch(Box::new(leaf(magenta)), Box::new(leaf(cyan))), + &branch(Box::new(leaf(magenta)), Box::new(leaf(magenta))))); + + println!("Assertions all succeeded!"); +} |