exampl

szabgab · Jul 18, 2024 · fc8adb3 · fc8adb3
1 parent 41cd867
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diff --git a/slides/rust/examples/macros/optional-parameter/Cargo.lock b/slides/rust/examples/macros/optional-parameter/Cargo.lock
diff --git a/slides/rust/examples/macros/optional-parameter/Cargo.toml b/slides/rust/examples/macros/optional-parameter/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "optional-parameter"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/slides/rust/examples/macros/optional-parameter/out.out b/slides/rust/examples/macros/optional-parameter/out.out
@@ -0,0 +1,8 @@
+ping localhost
+ping remote
+ping remote
+ping remote
+ping remote
+ping localhost
+ping localhost
+ping localhost
diff --git a/slides/rust/examples/macros/optional-parameter/src/main.rs b/slides/rust/examples/macros/optional-parameter/src/main.rs
@@ -0,0 +1,27 @@
+macro_rules! ping {
+
+    ($address: expr) => {
+        ping($address, 4);
+    };
+    ($address: expr, $repeat: expr) => {
+        ping($address, $repeat);
+    };
+}
+
+fn ping(address: &str, mut repeat: u8) {
+    while repeat > 0 {
+        println!("ping {address}");
+        repeat -= 1;
+    }
+}
+fn main() {
+    ping("localhost", 1);
+
+    //ping("remote");
+    ping!("remote");
+
+    ping!("localhost", 3);
+}
+
+
+
diff --git a/slides/rust/macros.md b/slides/rust/macros.md
@@ -116,13 +116,18 @@ cargo run bar
 
 
 ## Macro ok! to replace unwrap
-{id: macri-ok}
+{id: macro-ok}
 
 Seen in the tests of the sqlite crate.
 
 ```
 macro_rules! ok(($result:expr) => ($result.unwrap()));
 ```
 
+## Optional function parameters using macros
+{id: optional-function-parameters-using-macro}
+
+![](examples/macros/optional-parameter/src/main.rs)
+![](examples/macros/optional-parameter/out.out)