extract setMaxValue

day02-hard/src/main.zig

@@ -1,5 +1,14 @@
 const std = @import("std");
 
+fn setMaxValue(field: anytype, new_value: anytype) void {
+    comptime {
+        if (!std.meta.trait.isPtrTo(@typeInfo(@TypeOf(new_value)))(@TypeOf(field))) {
+            @compileError("Expects field to be pointer type to new_value.");
+        }
+    }
+    field.* = @max(field.*, new_value);
+}
+
 const Cubes = struct {
     red: u32 = 0,
     green: u32 = 0,
@@ -10,21 +19,15 @@ const Cubes = struct {
     }
 
     fn setRed(self: *Cubes, value: u32) void {
-        if (self.red < value) {
-            self.red = value;
-        }
+        setMaxValue(&self.red, value);
     }
 
     fn setGreen(self: *Cubes, value: u32) void {
-        if (self.green < value) {
-            self.green = value;
-        }
+        setMaxValue(&self.green, value);
     }
 
     fn setBlue(self: *Cubes, value: u32) void {
-        if (self.blue < value) {
-            self.blue = value;
-        }
+        setMaxValue(&self.blue, value);
     }
 };