enums - Polymorphism in Rust -

enums - Polymorphism in Rust -

i'm writing board game ai in rust. there multiple rulesets game , i'd have rules logic separated board layout (they mixed). in language ruby i'd have separate rule sets implement same interface. in rust thought using trait , parameterizing board ruleset want utilize (e.g. board<rules1>::new()). saving object implements trait in struct (like board) not allowed. of course of study turn rules enum, looks bit messy me then, because can't define separate implementations members of enum. using pattern matching work, splits functionality along function axis , not along struct axis. have live or there way?

the next code i'd use:

pub struct rules1; pub struct rules2; trait rules { fn move_allowed() -> bool; } impl rules rules1 { fn move_allowed() -> bool { true } } impl rules rules2 { fn move_allowed() -> bool { false } } struct board<r: rules> { rules: r } fn main() {}

it produces next error:

test.rs:20:1: 22:2 error: trait bounds not allowed in construction definitions test.rs:20 struct board<r: rules> { test.rs:21 rules: r test.rs:22 } error: aborting due previous error

the code presented in question works on recent versions of rust, trait bounds on structs allowed.

for reference, original reply follows:

pub struct rules1; pub struct rules2; trait rules { fn move_allowed(&self) -> bool; } impl rules rules1 { fn move_allowed(&self) -> bool { true } } impl rules rules2 { fn move_allowed(&self) -> bool { false } } struct board<r> { rules: r } impl<r:rules> board<r> { fn move_allowed(&self) -> bool { self.rules.move_allowed() } } fn main() { allow board = board { rules: rules2 }; assert!(!board.move_allowed()); }

you need refine in trait implementation, not struct definition.

enums polymorphism rust