basic printers, type printers, some fixes, part of expression printers

include/basic_nodes.hpp

@@ -8,11 +8,11 @@
 namespace nodes {
 
 enum class Modifier {
-  OUT,      // -> x
-  IN,       // <- x
-  REF,      // <> x
-  OR_FALSE, // x?
-  OR_PANIC, // x!
+  OUT,       // -> x
+  IN,        // <- x
+  REF,       // <> x
+  OR_FALSE,  // x?
+  OR_RETURN, // x!
   NONE,
 };
 
@@ -53,6 +53,16 @@ public:
     return std::nullopt;
   }
 
+  std::variant<double, long long, std::string, char, bool, unit, null> *
+  get_any() {
+    return &value_;
+  }
+
+  const std::variant<double, long long, std::string, char, bool, unit, null> *
+  get_any() const {
+    return &value_;
+  }
+
 private:
   std::variant<double, long long, std::string, char, bool, unit, null> value_;
 };