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Improve macro subsection

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Philipp Oppermann
2015-10-23 01:42:40 +02:00
parent 6602332094
commit cc73673305
1 changed files with 1 additions and 1 deletions
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_drafts/printing-to-screen.md
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@@ -352,7 +352,7 @@ macro_rules! print {
``` ```
Instead of a `_print` function, we call the `write_fmt` method of our static `Writer`. Since we're using a method from the `Write` trait, we need to import it before. The additional `unwrap()` at the end panics if printing isn't successful. But since we always return `Ok` in `write_str`, that should not happen. Instead of a `_print` function, we call the `write_fmt` method of our static `Writer`. Since we're using a method from the `Write` trait, we need to import it before. The additional `unwrap()` at the end panics if printing isn't successful. But since we always return `Ok` in `write_str`, that should not happen.
Notice the additional scope around the macro: It's `=> ({…})` instead of `=> (…)`. The additional `{}` avoid a silent import of the `Write` trait on macro expansion. Note the additional `{}` scope around the macro: I wrote `=> ({…})` instead of `=> (…)`. The additional `{}` avoids that the `Write` trait is silently imported when `print` is used.
### Clearing the screen ### Clearing the screen
We can now use `println!` to add a rather trivial function to clear the screen: We can now use `println!` to add a rather trivial function to clear the screen: