Attribute Macro guard_let::guard_let

#[guard_let]

Guard let for rust.

use guard_let::guard_let;

enum Enum {
   A(String),
   B(usize),
   C(Struct),
}

struct Struct {
   foo: String,
}

fn eat_string(_: String) {}

#[guard_let]
fn simple_ident() {
   let v = Enum::A(String::from(""));

   guard_let!(v as Enum::A(s), {
       // Type of v is Enum at here.
       println!("v is not A: {:?}", v);
       return;
   });

   // Type of s is String
   eat_string(s)
}

#[guard_let]
fn pattern() {
   let v = Enum::A(String::from(""));

   guard_let!(v as Enum::C(Struct { foo }), {
       // Type of v is Enum at here.
       println!("v is not C: {:?}", v);
       return;
   });

   // Type of s is String
   eat_string(foo)
}