feat: if let 语句 — if let Option::Some = expr { ... }

2026-06-06 15:20:34 +08:00
parent 0e1f8c5795
commit e02cc7b1d6
4 changed files with 98 additions and 39 deletions
@@ -0,0 +1,22 @@
+enum Option { Some(i64), None }
+
+fn main() -> i64 {
+    let s = Option::Some(42);
+    let n = Option::None;
+
+    // if let: 匹配 Some
+    if let Option::Some = s {
+        print_i64(100);
+    } else {
+        print_i64(0);
+    }
+
+    // if let: 匹配 None（走 else）
+    if let Option::Some = n {
+        print_i64(999);
+    } else {
+        print_i64(200);
+    }
+
+    return 0;
+}