Rust enums

Author: nimrod-starkware

blocks_pdf/enums.pdf

@@ -0,0 +1,65 @@
+#import "../src/block_by_block.typ": *
+
+#set page(
+  margin: (
+    top: 20pt,
+    bottom: 0pt,
+    left: 50pt,
+    right: 50pt,
+  ),
+  background: [#page_border(blue)],
+)
+#set text(size: 12.0pt)
+
+#logo("enums")
+
+#block_header(7, [Rust enums are great!])
+
+#what
+\ Rust enums let you encode valid states in the type system, these states are enforced at compilation time.
+
+#why
+\ The compiler then enforces correctness: you can’t create invalid combinations of fields, you avoid runtime checks and redundancy.
+
+#how
+#bad_code[```rust
+struct LoggingConfig {
+    enabled: bool,
+    level: LogLevel, // What should be here when logging is disabled?
+}
+```]
+Let's try to make it optional!
+#bad_code[```rust
+struct LoggingConfig {
+    enabled: bool,
+    level: Option<LogLevel>,
+}
+impl LoggingConfig {
+    fn log(&self, message: &str) {
+        if self.enabled {
+            // Why taking the risk of panicking here?
+            let level = self.level.unwrap();
+            log(level, message);
+        }
+    }
+}
+```]
+We should do that instead!
+#code[```rust
+enum LoggingConfig {
+    Disabled,
+    Enabled(LogLevel),
+}
+impl LoggingConfig {
+    fn log(&self, message: &str) {
+          if let Self::Enabled(level) = self { // No risk of panicking.
+              log(level, message);
+        }
+    }
+}
+```]
+#tip[
+  You should consider using structs over enums for (de)serializable objects, as the schema for enums is less compatible with other programming languages (e.g Python).
+]
+#v(-32pt)
+#slack