2 files changed, 43 insertions, 10 deletions

diff --git a/src/core/parser/ParserStack.cpp b/src/core/parser/ParserStack.cpp
index 5e801ee..ff2647d 100644
--- a/src/core/parser/ParserStack.cpp
+++ b/src/core/parser/ParserStack.cpp
@@ -37,6 +37,11 @@ void Handler::data(const std::string &data, int field)
 	}
 }
 
+void Handler::child(std::shared_ptr<Handler> handler)
+{
+	// Do nothing here
+}
+
 /* Class HandlerDescriptor */
 
 HandlerInstance HandlerDescriptor::create(const ParserContext &ctx,
@@ -45,7 +50,14 @@ HandlerInstance HandlerDescriptor::create(const ParserContext &ctx,
                                           const Variant &args) const
 {
 	Handler *h = ctor(ctx, name, targetState, parentState, isChild);
-	h->start(args);
+
+	// Canonicalize the arguments
+	Variant arguments = args;
+	if (argsType != nullptr) {
+		argsType->build(arguments, ctx.logger);
+	}
+
+	h->start(arguments);
 	return HandlerInstance(h, this);
 }
 
@@ -67,8 +79,8 @@ static LoggableException invalidCommand(const std::string &name,
 		    std::string{"Expected "} +
 		    (expected.size() == 1 ? std::string{"\""}
 		                          : std::string{"one of \""}) +
-		    Utils::join(expected, "\", \"") + std::string{"\", but got \""} + name +
-		    std::string{"\""}};
+		    Utils::join(expected, "\", \"") + std::string{"\", but got \""} +
+		    name + std::string{"\""}};
 	}
 }
 
diff --git a/src/core/parser/ParserStack.hpp b/src/core/parser/ParserStack.hpp
index 233f4f9..93180b4 100644
--- a/src/core/parser/ParserStack.hpp
+++ b/src/core/parser/ParserStack.hpp
@@ -38,6 +38,8 @@
 #include <vector>
 
 #include <core/common/Variant.hpp>
+#include <core/common/Logger.hpp>
+#include <core/model/Typesystem.hpp>
 
 #include "Parser.hpp"
 
@@ -61,9 +63,6 @@ class Handler {
 private:
 	Rooted<Node> node;
 
-protected:
-	void setNode(Handle<Node> node) { this->node = node; }
-
 public:
 	/**
 	 * Reference to the ParserContext instance that should be used to resolve
@@ -132,7 +131,7 @@ public:
 	virtual void start(const Variant &args) = 0;
 
 	/**
-	 * Called whenever the command for which this handler
+	 * Called whenever the command for which this handler is defined ends.
 	 */
 	virtual void end() = 0;
 
@@ -153,7 +152,7 @@ public:
 	 *
 	 * @param handler is a reference at the child Handler instance.
 	 */
-	virtual void child(std::shared_ptr<Handler> handler){};
+	virtual void child(std::shared_ptr<Handler> handler);
 };
 
 /**
@@ -212,12 +211,34 @@ struct HandlerDescriptor {
 	 */
 	const bool arbitraryChildren;
 
+	/**
+	 * Pointer pointing at a StructType describing the layout of the given when
+	 * a new Handler instance is instantiated.
+	 */
+	const Rooted<model::StructType> argsType;
+
+	/**
+	 * Constructor of the HandlerDescriptor class.
+	 *
+	 * @param parentStates is a set of states in which a new handler of this
+	 * type may be instantiated.
+	 * @param ctor is a function pointer pointing at a function that
+	 * instantiates the acutal Handler instance.
+	 * @param targetState is the state the ParserStack switches to after
+	 * instantiating an in instance of the described Handler instances.
+	 * @param arbitraryChildren allows the Handler instance to handle any child
+	 * node.
+	 * @param argsType is a struct type describing the arguments that can be
+	 * passed to the Handler or nullptr if no check should be performed.
+	 */
 	HandlerDescriptor(std::set<State> parentStates, HandlerConstructor ctor,
-	                  State targetState, bool arbitraryChildren = false)
+	                  State targetState, bool arbitraryChildren = false,
+	                  Handle<model::StructType> argsType = nullptr)
 	    : parentStates(std::move(parentStates)),
 	      ctor(ctor),
 	      targetState(targetState),
-	      arbitraryChildren(arbitraryChildren)
+	      arbitraryChildren(arbitraryChildren),
+	      argsType(argsType)
 	{
 	}