added conversion-based uniform API

src/typed-geometry/functions/random/uniform.hh

@@ -25,7 +25,8 @@
 #include "random.hh"
 
 /*
- * uniform(rng)       - fair coin flip
+ * uniform<T>(rng)    - uniform sample for T's where no parameter is needed
+ * uniform(rng)       - returns an object that implicitly converts to T (and calls uniform<T>(rng))
  * uniform(rng, a, b) - uniform between a..b (inclusive!)
  * uniform(rng, obj)  - uniform sample from obj
  *
@@ -47,6 +48,22 @@ struct sampler
 {
     static_assert(sizeof(T) >= 0, "sampling of this type not supported without parameters");
 };
+
+// NOTE: this class should not be saved
+template <class Rng>
+struct uniform_sampler
+{
+    explicit uniform_sampler(Rng& rng) : rng(rng) {}
+
+    template <class T>
+    operator T() &&
+    {
+        return sampler<T>::uniform(rng);
+    }
+
+private:
+    Rng& rng;
+};
 }
 
 template <class T, class Rng>
@@ -55,6 +72,12 @@ template <class T, class Rng>
     return detail::sampler<T>::uniform(rng);
 }
 
+template <class Rng>
+[[nodiscard]] constexpr detail::uniform_sampler<Rng> uniform(Rng& rng)
+{
+    return detail::uniform_sampler<Rng>{rng};
+}
+
 template <class Rng>
 [[nodiscard]] constexpr f32 uniform(Rng& rng, f32 a, f32 b)
 {