1 files changed, 51 insertions, 0 deletions
diff --git a/decor/on_condition.go b/decor/on_condition.go
new file mode 100644
index 0000000..f4626c3
--- /dev/null
+++ b/decor/on_condition.go
@@ -0,0 +1,51 @@
+package decor
+
+// OnCondition applies decorator only if a condition is true.
+//
+//	`decorator` Decorator
+//
+//	`cond` bool
+func OnCondition(decorator Decorator, cond bool) Decorator {
+	return Conditional(cond, decorator, nil)
+}
+
+// OnPredicate applies decorator only if a predicate evaluates to true.
+//
+//	`decorator` Decorator
+//
+//	`predicate` func() bool
+func OnPredicate(decorator Decorator, predicate func() bool) Decorator {
+	return Predicative(predicate, decorator, nil)
+}
+
+// Conditional returns decorator `a` if condition is true, otherwise
+// decorator `b`.
+//
+//	`cond` bool
+//
+//	`a` Decorator
+//
+//	`b` Decorator
+func Conditional(cond bool, a, b Decorator) Decorator {
+	if cond {
+		return a
+	} else {
+		return b
+	}
+}
+
+// Predicative returns decorator `a` if predicate evaluates to true,
+// otherwise decorator `b`.
+//
+//	`predicate` func() bool
+//
+//	`a` Decorator
+//
+//	`b` Decorator
+func Predicative(predicate func() bool, a, b Decorator) Decorator {
+	if predicate() {
+		return a
+	} else {
+		return b
+	}
+}