feat: encoding accessor in foundry & less constrained forge setup

Allow forge setup to be called on nullptr and have an empty constructor
setup. Useful to build up forge vectors in one pass instead of add/setup
loops.

eo/src/eoAlgoFoundry.h

@@ -62,6 +62,11 @@ class eoAlgoFoundry : public eoAlgo<EOT>
             return _size;
         }
 
+        std::vector<size_t> encoding() const
+        {
+            return _encoding;
+        }
+
     protected:
         const size_t _size;
         std::vector<size_t> _encoding;

eo/src/eoForge.h

@@ -265,12 +265,23 @@ class eoForgeVector : public std::vector<eoForgeInterface<Itf>*>
         template<class Op, typename... Args>
         void setup(size_t index, Args... args)
         {
-            assert(this->at(index) != nullptr);
+            assert(index < this->size());
-            delete this->at(index);
+            delete this->at(index); // Silent on nullptr.
             auto pfo = new eoForgeOperator<Itf,Op,Args...>(args...);
             this->at(index) = pfo;
         }
 
+        /** Specialization for empty constructors.
+         */
+        template<class Op>
+        void setup(size_t index)
+        {
+            assert(index < this->size());
+            delete this->at(index);
+            auto pfo = new eoForgeOperator<Itf,Op>;
+            this->at(index) = pfo;
+        }
+
         /** Instanciate the operator managed at the given index.
          */
         Itf& instanciate(size_t index)