Introduce FunctionCall and way to register native functions

src/server/as/ast.cpp

@@ -103,3 +103,35 @@ Value FunctionDefinition::eval(VM& vm) {
 	m_body->eval(vm);
 	return vm.get_return_value();
 }
+
+FunctionCall::FunctionCall(VM& vm, FunctionType func_type, unsigned address, std::vector<std::unique_ptr<Expression>> arguments) :
+	Expression(ValueType::VALUE_TYPE_VOID),
+	m_func_type(func_type),
+	m_address(address),
+	m_arguments(std::move(arguments))
+{
+	switch(func_type) {
+	case FunctionType::FUNCTION_NORMAL:
+		// TODO
+		break;
+	case FunctionType::FUNCTION_NATIVE:
+		m_result_type = var_type_to_value_type(vm.get_native_function_by_address(address).m_result_type);
+		break;
+	}
+}
+
+Value FunctionCall::eval(VM& vm) {
+	std::vector<Value> argument_values;
+	argument_values.reserve(m_arguments.size());
+	for(std::unique_ptr<Expression>& arg : m_arguments)
+		argument_values.push_back(arg->eval(vm));
+
+	switch(m_func_type) {
+	case FunctionType::FUNCTION_NORMAL:
+		// TODO
+		break;
+	case FunctionType::FUNCTION_NATIVE:
+		return vm.get_native_function_by_address(m_address).m_func(vm, argument_values);
+	}
+	return Value{};
+}

src/server/as/ast.hpp

@@ -100,6 +100,18 @@ namespace polygun::server::as {
 		std::vector<VarType> m_argument_types;
 		std::unique_ptr<StatementBlock> m_body;
 	};
+
+	class FunctionCall final : public Expression {
+	public:
+		FunctionCall(VM& vm, FunctionType func_type, unsigned address, std::vector<std::unique_ptr<Expression>> arguments);
+
+		virtual Value eval(VM& vm) override;
+
+	private:
+		FunctionType m_func_type;
+		unsigned m_address;
+		std::vector<std::unique_ptr<Expression>> m_arguments;
+	};
 }
 
 #endif // POLYGUN_SERVER_AS_AST_HPP

src/server/as/value.cpp

@@ -27,5 +27,15 @@ SOFTWARE.
 #include <algorithm>
 
 polygun::server::as::ValueType polygun::server::as::get_wider_type(polygun::server::as::ValueType first, polygun::server::as::ValueType second) {
-  return static_cast<ValueType>(std::max(first, second));
+	return static_cast<ValueType>(std::max(first, second));
+}
+
+polygun::server::as::ValueType polygun::server::as::var_type_to_value_type(polygun::server::as::VarType var_type) {
+	if(var_type<=VarType::VAR_TYPE_BOOL)
+		return static_cast<ValueType>(var_type);
+	if(var_type<=VarType::VAR_TYPE_UINT64)
+		return ValueType::VALUE_TYPE_UINT;
+	if(var_type<=VarType::VAR_TYPE_INT64)
+		return ValueType::VALUE_TYPE_INT;
+	return ValueType::VALUE_TYPE_DOUBLE;
 }

src/server/as/value.hpp

@@ -44,6 +44,7 @@ namespace polygun::server::as {
 	};
 
 	enum VarType {
+		VAR_TYPE_VOID,
 		VAR_TYPE_BOOL,
 		VAR_TYPE_UINT8,
 		VAR_TYPE_UINT16,
@@ -57,7 +58,13 @@ namespace polygun::server::as {
 		VAR_TYPE_DOUBLE
 	};
 
+	enum FunctionType {
+		FUNCTION_NORMAL,
+		FUNCTION_NATIVE
+	};
+
 	ValueType get_wider_type(ValueType first, ValueType second);
+	ValueType var_type_to_value_type(VarType var_type);
 	template<typename T>
 	T value_as(const Value& value, ValueType type) {
 		switch(type) {

src/server/as/vm.cpp

@@ -30,9 +30,26 @@ VM::VM(unsigned storage_size) :
 	m_storage_size(storage_size),
 	m_stack(new uint8_t[storage_size]),
 	m_stack_ptr(0),
-	m_return_value()
+	m_return_value(),
+	m_native_functions(),
+	m_native_function_addresses()
 {}
 
 VM::~VM() {
 	delete[] m_stack;
 }
+
+void VM::register_function(const std::string& name, VarType result_type, const std::vector<VarType>& argument_types, Value(*func)(VM&, const std::vector<Value>&)) {
+	m_native_function_addresses[name] = m_native_functions.size();
+	const NativeFunction native_function {
+		result_type,
+		argument_types,
+		func
+	};
+	m_native_functions.push_back(native_function);
+}
+
+const VM::NativeFunction& VM::get_native_function_by_address(unsigned address) {
+	assert(address<m_native_functions.size());
+	return m_native_functions[address];
+}

src/server/as/vm.hpp

@@ -27,6 +27,9 @@ SOFTWARE.
 
 #include <cassert>
 #include <cstdint>
+#include <map>
+#include <string>
+#include <vector>
 
 #include "server/as/value.hpp"
 
@@ -37,11 +40,18 @@ namespace polygun::server::as {
 			LOCATION_STACK,
 			LOCATION_STATIC
 		};
+		struct NativeFunction {
+			VarType m_result_type;
+			std::vector<VarType> m_argument_types;
+			Value(*m_func)(VM&, const std::vector<Value>&);
+		};
 
 	public:
 		VM(unsigned storage_size);
 		~VM();
 
+		void register_function(const std::string& name, VarType result_type, const std::vector<VarType>& argument_types, Value(*func)(VM&, const std::vector<Value>&));
+
 		template<typename T>
 		void set_value_at(Location location, unsigned addr, T value) {
 			assert(addr<m_storage_size);
@@ -68,12 +78,16 @@ namespace polygun::server::as {
 		}
 		unsigned get_stack_ptr() const { return m_stack_ptr; }
 		const Value& get_return_value() const { return m_return_value; }
+		const NativeFunction& get_native_function_by_address(unsigned address);
 
 	private:
 		unsigned m_storage_size;
 		uint8_t* m_stack;
 		unsigned m_stack_ptr;
 		Value m_return_value;
+		std::vector<NativeFunction> m_native_functions;
+		// Maps function name to index in std::vector above
+		std::map<std::string, unsigned> m_native_function_addresses;
 	};
 }
 

src/server/server.cpp

@@ -39,6 +39,8 @@ SOFTWARE.
 #include "common/math/rect3d.hpp"
 #include "common/logger.hpp"
 #include "common/world/chunk.hpp"
+#include "server/as/ast.hpp"
+#include "server/as/vm.hpp"
 
 using namespace polygun::server;
 
@@ -46,6 +48,11 @@ static const float DAY_TIME_INTERVAL = 10.0f*60.0f/65536.0f;
 
 static Server* g_current_server = nullptr;
 
+as::Value test_native_function(as::VM& vm, const std::vector<as::Value>& args) {
+	LOG_INFO("%d", args[0].i);
+	return as::Value{};
+}
+
 Server::Server(std::atomic<bool>* running_atomic, std::optional<unsigned short> port_override) :
 	m_config(),
 	m_running(running_atomic?running_atomic:new std::atomic<bool>),
@@ -78,6 +85,18 @@ Server::Server(std::atomic<bool>* running_atomic, std::optional<unsigned short>
 	m_player_storage.load();
 	m_chunk_manager.load_map_from_file(m_config.m_default_map);
 	m_mod_manager.enumerate_modules();
+
+	as::Value val1;
+	val1.i = 10;
+	as::Value val2;
+	val2.i = 5;
+	as::VM vm(1024);
+	vm.register_function("test_native_function", as::VarType::VAR_TYPE_VOID, std::vector<as::VarType>{as::VarType::VAR_TYPE_INT32}, test_native_function);
+	std::unique_ptr<as::StatementBlock> block = std::make_unique<as::StatementBlock>();
+	std::vector<std::unique_ptr<as::Expression>> arguments;
+	arguments.push_back(std::make_unique<as::BinaryExpression>(as::BinaryExpression::Operation::OPERATION_MUL, std::make_unique<as::NumericExpression>(val1, as::ValueType::VALUE_TYPE_INT), std::make_unique<as::NumericExpression>(val2, as::ValueType::VALUE_TYPE_INT)));
+	block->add_expression(std::make_unique<as::FunctionCall>(vm, as::FunctionType::FUNCTION_NATIVE, 0, std::move(arguments)));
+	block->eval(vm);
 }
 
 Server::~Server() {