Calling functions in the implementation of a trait function
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Consider the following example: I have a trait Foo with a function foo() and an associated type F, and a struct Bar which implements Foo.
Bar's implementation of foo() is so complicated that I would like to have it call a smaller function func() to help structure the code. As I understand it, I can't add functions to the impl Foo for Bar block, because func() isn't part of the Foo trait. So they have to be in their own impl Bar block. Here is what I finally came up with:
trait Foo {
type F;
fn foo(&self) -> Self::F;
}
struct Bar {}
impl Foo for Bar {
type F = i32;
fn foo(&self) -> Self::F {
(self as &Bar).func(3)
}
}
impl Bar {
fn func(&self, f: <Self as Foo>::F) -> <Self as Foo>::F {
f+1
}
}
fn main() {
let b = Bar {};
println!("{}",b.foo());
}
But is this the idiomatic way of solving my issue? Of somewhat lesser importance, if I need more helper functions like func(), is there a way to shorten <Self as Foo>::F? (Inserting a type declaration in the top level of the impl Bar block certainly doesn't work the way it would inside a function scope.) Would I want to?
rust trait
asked 14 hours ago
ArthurArthur
1165
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add a comment |
$begingroup$
Consider the following example: I have a trait Foo with a function foo() and an associated type F, and a struct Bar which implements Foo.
Bar's implementation of foo() is so complicated that I would like to have it call a smaller function func() to help structure the code. As I understand it, I can't add functions to the impl Foo for Bar block, because func() isn't part of the Foo trait. So they have to be in their own impl Bar block. Here is what I finally came up with:
trait Foo {
type F;
fn foo(&self) -> Self::F;
}
struct Bar {}
impl Foo for Bar {
type F = i32;
fn foo(&self) -> Self::F {
(self as &Bar).func(3)
}
}
impl Bar {
fn func(&self, f: <Self as Foo>::F) -> <Self as Foo>::F {
f+1
}
}
fn main() {
let b = Bar {};
println!("{}",b.foo());
}
But is this the idiomatic way of solving my issue? Of somewhat lesser importance, if I need more helper functions like func(), is there a way to shorten <Self as Foo>::F? (Inserting a type declaration in the top level of the impl Bar block certainly doesn't work the way it would inside a function scope.) Would I want to?
rust trait
asked 14 hours ago
ArthurArthur
1165
$endgroup$
$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago
add a comment |
$begingroup$
Consider the following example: I have a trait Foo with a function foo() and an associated type F, and a struct Bar which implements Foo.
Bar's implementation of foo() is so complicated that I would like to have it call a smaller function func() to help structure the code. As I understand it, I can't add functions to the impl Foo for Bar block, because func() isn't part of the Foo trait. So they have to be in their own impl Bar block. Here is what I finally came up with:
trait Foo {
type F;
fn foo(&self) -> Self::F;
}
struct Bar {}
impl Foo for Bar {
type F = i32;
fn foo(&self) -> Self::F {
(self as &Bar).func(3)
}
}
impl Bar {
fn func(&self, f: <Self as Foo>::F) -> <Self as Foo>::F {
f+1
}
}
fn main() {
let b = Bar {};
println!("{}",b.foo());
}
But is this the idiomatic way of solving my issue? Of somewhat lesser importance, if I need more helper functions like func(), is there a way to shorten <Self as Foo>::F? (Inserting a type declaration in the top level of the impl Bar block certainly doesn't work the way it would inside a function scope.) Would I want to?
rust trait
asked 14 hours ago
ArthurArthur
1165
$endgroup$
Consider the following example: I have a trait Foo with a function foo() and an associated type F, and a struct Bar which implements Foo.
Bar's implementation of foo() is so complicated that I would like to have it call a smaller function func() to help structure the code. As I understand it, I can't add functions to the impl Foo for Bar block, because func() isn't part of the Foo trait. So they have to be in their own impl Bar block. Here is what I finally came up with:
trait Foo {
type F;
fn foo(&self) -> Self::F;
}
struct Bar {}
impl Foo for Bar {
type F = i32;
fn foo(&self) -> Self::F {
(self as &Bar).func(3)
}
}
impl Bar {
fn func(&self, f: <Self as Foo>::F) -> <Self as Foo>::F {
f+1
}
}
fn main() {
let b = Bar {};
println!("{}",b.foo());
}
But is this the idiomatic way of solving my issue? Of somewhat lesser importance, if I need more helper functions like func(), is there a way to shorten <Self as Foo>::F? (Inserting a type declaration in the top level of the impl Bar block certainly doesn't work the way it would inside a function scope.) Would I want to?
rust trait
rust trait
asked 14 hours ago
ArthurArthur
1165
asked 14 hours ago
ArthurArthur
1165
asked 14 hours ago
ArthurArthur
1165
asked 14 hours ago
ArthurArthur
1165
asked 14 hours ago
ArthurArthur
1165
1165
$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago
add a comment |
$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago
$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago
$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago
add a comment |
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$begingroup$
As per the rules in the the help center, Code Review requires real code. Hypothetical foo/bar examples are off-topic for Code Review.
$endgroup$
– 200_success
51 mins ago