right let's try this one again

This commit is contained in:
olivia
2018-11-09 20:31:14 +01:00
parent 850a13e913
commit f7846af7ac
60 changed files with 130 additions and 939 deletions

64
exercises/macros/macros1.rs Executable file
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// macros1.rs
// Make me compile! Scroll down for hints :)
macro_rules! my_macro {
() => {
println!("Check out my macro!");
};
}
fn main() {
my_macro();
}
// When you call a macro, you need to add something special compared to a
// regular function call. If you're stuck, take a look at what's inside
// `my_macro`.

73
exercises/macros/macros2.rs Executable file
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// macros2.rs
// Make me compile! Scroll down for hints :)
fn main() {
my_macro!();
}
macro_rules! my_macro {
() => {
println!("Check out my macro!");
};
}
// Macros don't quite play by the same rules as the rest of Rust, in terms of
// what's available where.
// Unlike other things in Rust, the order of "where you define a macro" versus
// "where you use it" actually matters.

75
exercises/macros/macros3.rs Executable file
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// macros3.rs
// Make me compile, without taking the macro out of the module! Scroll down for hints :)
mod macros {
macro_rules! my_macro {
() => {
println!("Check out my macro!");
};
}
}
fn main() {
my_macro!();
}
// In order to use a macro outside of its module, you need to do something
// special to the module to lift the macro out into its parent.
// The same trick also works on "extern crate" statements for crates that have
// exported macros, if you've seen any of those around.

77
exercises/macros/macros4.rs Executable file
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// macros4.rs
// Make me compile! Scroll down for hints :)
macro_rules! my_macro {
() => {
println!("Check out my macro!");
}
($val:expr) => {
println!("Look at this other macro: {}", $val);
}
}
fn main() {
my_macro!();
my_macro!(7777);
}
// You only need to add a single character to make this compile.
// The way macros are written, it wants to see something between each
// "macro arm", so it can separate them.