46 lines
1.1 KiB
Rust
46 lines
1.1 KiB
Rust
// run-pass
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#![allow(non_camel_case_types)]
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trait to_str {
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fn to_string_(&self) -> String;
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}
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impl to_str for isize {
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fn to_string_(&self) -> String { self.to_string() }
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}
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impl to_str for String {
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fn to_string_(&self) -> String { self.clone() }
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}
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impl to_str for () {
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fn to_string_(&self) -> String { "()".to_string() }
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}
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trait map<T> {
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fn map<U, F>(&self, f: F) -> Vec<U> where F: FnMut(&T) -> U;
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}
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impl<T> map<T> for Vec<T> {
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fn map<U, F>(&self, mut f: F) -> Vec<U> where F: FnMut(&T) -> U {
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let mut r = Vec::new();
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for i in self {
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r.push(f(i));
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}
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r
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}
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}
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fn foo<U, T: map<U>>(x: T) -> Vec<String> {
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x.map(|_e| "hi".to_string() )
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}
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fn bar<U:to_str,T:map<U>>(x: T) -> Vec<String> {
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x.map(|_e| _e.to_string_() )
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}
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pub fn main() {
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assert_eq!(foo(vec![1]), ["hi".to_string()]);
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assert_eq!(bar::<isize, Vec<isize> >(vec![4, 5]), ["4".to_string(), "5".to_string()]);
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assert_eq!(bar::<String, Vec<String> >(vec!["x".to_string(), "y".to_string()]),
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["x".to_string(), "y".to_string()]);
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assert_eq!(bar::<(), Vec<()>>(vec![()]), ["()".to_string()]);
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}
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