[Solved] Auto gen enum options as function?

1
  1. Consider the following code:

pub enum Foo {
    A(i32),
    B(f32, f32),
}

impl Foo {
    pub fn new_a(data: i32) -> Foo { Foo::A(data) }
    pub fn new_b(lhs: f32, rhs: f32) -> Foo { Foo::B(lhs, rhs) }
}
  1. In this code, is there a way to auto gen new_a, new_b? The idea is that every "choice" of a enum can also be viewed as a "function" which takes its args and outputs a obj of the enum type.
2

Not automatically, though the names of the enum variants act as exactly the functions you've written (i.e. they can be passed to map, etc, as functions). What's your use case?

1 Like
3

This is, for reasons of implementation, literally a function call exactly as you want, and (as noted above) can be called by path instead of a closure.

See the paragraph preceeding the last example of the section on function pointers, which I tweaked after learning about this in an earlier thread here.

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4

@cbiffle , @dcarosone : LOL. Problem = entirely due to my lack of knowledge about enum's -- that they ALREADY SERVE AS FUNCTIONS. :slight_smile:

There is no longer a question here, this was due 100% to me not knowing about this particular feature of Rust. :slight_smile:

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5

Great! Happy to help.