mcp-vala/examples/calculator-server.vala

/*
 * Calculator MCP Server Example
 *
 * This example demonstrates how to create an MCP server that provides
 * mathematical calculation tools. It shows how to implement and register
 * multiple tools with different capabilities.
 *
 * Compile with:
 * valac --pkg mcp-vala --pkg json-glib-1.0 --pkg gee-0.8 --pkg posix calculator-server.vala -o calculator-server
 */

using Mcp;
using Posix;

/**
 * Calculator server that provides mathematical tools.
 */
public class CalculatorServer : GLib.Object {
    private Mcp.Core.Server server;
    
    /**
     * Creates a new CalculatorServer.
     */
    public CalculatorServer () {
        // Create server information
        var server_info = new Mcp.Types.Protocol.ServerInfo (
            "calculator-server",
            "1.0.0"
        );
        server_info.description = "MCP server providing mathematical calculation tools";
        
        // Create server capabilities with tools enabled
        var capabilities = new Mcp.Types.Protocol.ServerCapabilities ();
        capabilities.logging = true;
        capabilities.tools = new Mcp.Types.Protocol.ToolsCapabilities ();
        
        // Create server
        server = new Mcp.Core.Server (server_info, capabilities);
        
        // Register calculation tools
        setup_tools ();
    }
    
    /**
     * Sets up mathematical calculation tools.
     */
    private void setup_tools () {
        // Register basic calculator tool
        var basic_calculator = new BasicCalculatorTool ();
        try {
            server.tool_manager.register_executor ("basic_calculator", basic_calculator);
        } catch (Error e) {
            // Error handling
        }
        
        // Register advanced calculator tool
        var advanced_calculator = new AdvancedCalculatorTool ();
        try {
            server.tool_manager.register_executor ("advanced_calculator", advanced_calculator);
        } catch (Error e) {
            // Error handling
        }
        
        // Register unit converter tool
        var unit_converter = new UnitConverterTool ();
        try {
            server.tool_manager.register_executor ("unit_converter", unit_converter);
        } catch (Error e) {
            // Error handling
        }
    }
    
    /**
     * Runs the server.
     *
     * @return Exit code
     */
    public async int run () {
        try {
            // Start the server
            bool started = yield server.start ();
            if (!started) {
                return 1;
            }
            
            // Calculator server started successfully
            // Available tools: basic_calculator, advanced_calculator, unit_converter
            // Waiting for MCP client connections...
            
            // Run the main loop
            var main_loop = new MainLoop ();
            
            // Connect shutdown signal
            server.shutdown.connect (() => {
                main_loop.quit ();
            });
            
            main_loop.run ();
            
            return 0;
        } catch (Error e) {
            return 1;
        }
    }
}

/**
 * Basic calculator tool for simple arithmetic operations.
 */
public class BasicCalculatorTool : Mcp.Tools.BaseExecutor {
    /**
     * Creates a new BasicCalculatorTool.
     */
    public BasicCalculatorTool () {
        // Create tool definition using Variant
        var builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Add schema properties
        builder.add ("{sv}", "type", new Variant.string ("object"));
        builder.add ("{sv}", "description", new Variant.string ("Perform basic arithmetic operations"));
        
        var properties_builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Operation property
        var op_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        op_prop_builder.add ("{sv}", "type", new Variant.string ("string"));
        op_prop_builder.add ("{sv}", "description", new Variant.string ("Arithmetic operation to perform"));
        
        var enum_array_builder = new VariantBuilder (new VariantType ("as"));
        enum_array_builder.add ("s", "add");
        enum_array_builder.add ("s", "subtract");
        enum_array_builder.add ("s", "multiply");
        enum_array_builder.add ("s", "divide");
        enum_array_builder.add ("s", "power");
        enum_array_builder.add ("s", "modulo");
        op_prop_builder.add ("{sv}", "enum", enum_array_builder.end ());
        properties_builder.add ("{sv}", "operation", op_prop_builder.end ());
        
        // Operand 1 property
        var operand1_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        operand1_prop_builder.add ("{sv}", "type", new Variant.string ("number"));
        operand1_prop_builder.add ("{sv}", "description", new Variant.string ("First operand"));
        properties_builder.add ("{sv}", "operand1", operand1_prop_builder.end ());
        
        // Operand 2 property
        var operand2_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        operand2_prop_builder.add ("{sv}", "type", new Variant.string ("number"));
        operand2_prop_builder.add ("{sv}", "description", new Variant.string ("Second operand"));
        properties_builder.add ("{sv}", "operand2", operand2_prop_builder.end ());
        
        builder.add ("{sv}", "properties", properties_builder.end ());
        
        var required_array_builder = new VariantBuilder (new VariantType ("as"));
        required_array_builder.add ("s", "operation");
        required_array_builder.add ("s", "operand1");
        required_array_builder.add ("s", "operand2");
        builder.add ("{sv}", "required", required_array_builder.end ());
        
        var input_schema = builder.end ();
        
        var definition = new Mcp.Tools.Types.ToolDefinition ("basic_calculator", input_schema);
        definition.title = "Basic Calculator";
        definition.description = "Perform basic arithmetic operations (add, subtract, multiply, divide, power, modulo)";
        
        base (definition);
    }
    
    /**
     * {@inheritDoc}
     */
    protected override async Mcp.Tools.Types.CallToolResult do_execute (GLib.Variant arguments) throws Error {
        string operation = get_string_arg (arguments, "operation");
        double operand1 = get_double_arg (arguments, "operand1");
        double operand2 = get_double_arg (arguments, "operand2");
        
        double result = 0.0;
        
        switch (operation) {
            case "add":
                result = operand1 + operand2;
                break;
            case "subtract":
                result = operand1 - operand2;
                break;
            case "multiply":
                result = operand1 * operand2;
                break;
            case "divide":
                if (operand2 == 0) {
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Division by zero is not allowed");
                }
                result = operand1 / operand2;
                break;
            case "power":
                result = Math.pow (operand1, operand2);
                break;
            case "modulo":
                if (operand2 == 0) {
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Modulo by zero is not allowed");
                }
                result = (int)operand1 % (int)operand2;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown operation: %s".printf (operation));
        }
        
        // Create structured result using Variant
        var structured_data_builder = new VariantBuilder (new VariantType ("a{sv}"));
        structured_data_builder.add ("{sv}", "result", new Variant.double (result));
        structured_data_builder.add ("{sv}", "operation", new Variant.string (operation));
        structured_data_builder.add ("{sv}", "operand1", new Variant.double (operand1));
        structured_data_builder.add ("{sv}", "operand2", new Variant.double (operand2));
        structured_data_builder.add ("{sv}", "expression", new Variant.string ("%.2f %s %.2f = %.2f".printf (operand1, operation, operand2, result)));
        
        var structured_data = structured_data_builder.end ();
        
        return create_structured_result ("Calculation result: %.2f".printf (result), structured_data);
    }
}

/**
 * Advanced calculator tool for complex mathematical operations.
 */
public class AdvancedCalculatorTool : Mcp.Tools.BaseExecutor {
    /**
     * Creates a new AdvancedCalculatorTool.
     */
    public AdvancedCalculatorTool () {
        // Create tool definition using Variant
        var builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Add schema properties
        builder.add ("{sv}", "type", new Variant.string ("object"));
        builder.add ("{sv}", "description", new Variant.string ("Perform advanced mathematical operations"));
        
        var properties_builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Function property
        var func_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        func_prop_builder.add ("{sv}", "type", new Variant.string ("string"));
        func_prop_builder.add ("{sv}", "description", new Variant.string ("Mathematical function to apply"));
        
        var enum_array_builder = new VariantBuilder (new VariantType ("as"));
        enum_array_builder.add ("s", "sin");
        enum_array_builder.add ("s", "cos");
        enum_array_builder.add ("s", "tan");
        enum_array_builder.add ("s", "log");
        enum_array_builder.add ("s", "ln");
        enum_array_builder.add ("s", "sqrt");
        enum_array_builder.add ("s", "abs");
        enum_array_builder.add ("s", "ceil");
        enum_array_builder.add ("s", "floor");
        enum_array_builder.add ("s", "round");
        enum_array_builder.add ("s", "exp");
        func_prop_builder.add ("{sv}", "enum", enum_array_builder.end ());
        properties_builder.add ("{sv}", "function", func_prop_builder.end ());
        
        // Value property
        var value_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        value_prop_builder.add ("{sv}", "type", new Variant.string ("number"));
        value_prop_builder.add ("{sv}", "description", new Variant.string ("Value to apply the function to"));
        properties_builder.add ("{sv}", "value", value_prop_builder.end ());
        
        // Degrees property (for trigonometric functions)
        var degrees_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        degrees_prop_builder.add ("{sv}", "type", new Variant.string ("boolean"));
        degrees_prop_builder.add ("{sv}", "description", new Variant.string ("Whether to use degrees instead of radians (for trigonometric functions)"));
        degrees_prop_builder.add ("{sv}", "default", new Variant.boolean (false));
        properties_builder.add ("{sv}", "degrees", degrees_prop_builder.end ());
        
        builder.add ("{sv}", "properties", properties_builder.end ());
        
        var required_array_builder = new VariantBuilder (new VariantType ("as"));
        required_array_builder.add ("s", "function");
        required_array_builder.add ("s", "value");
        builder.add ("{sv}", "required", required_array_builder.end ());
        
        var input_schema = builder.end ();
        
        var definition = new Mcp.Tools.Types.ToolDefinition ("advanced_calculator", input_schema);
        definition.title = "Advanced Calculator";
        definition.description = "Perform advanced mathematical operations (trigonometric, logarithmic, etc.)";
        
        base (definition);
    }
    
    /**
     * {@inheritDoc}
     */
    protected override async Mcp.Tools.Types.CallToolResult do_execute (GLib.Variant arguments) throws Error {
        string function = get_string_arg (arguments, "function");
        double value = get_double_arg (arguments, "value");
        bool degrees = arguments.lookup_value ("degrees", null) != null ? arguments.lookup_value ("degrees", new VariantType ("b")).get_boolean () : false;
        
        double result = 0.0;
        
        // Convert to radians if degrees are specified for trigonometric functions
        double radians = degrees ? value * Math.PI / 180.0 : value;
        
        switch (function) {
            case "sin":
                result = Math.sin (radians);
                break;
            case "cos":
                result = Math.cos (radians);
                break;
            case "tan":
                result = Math.tan (radians);
                break;
            case "log":
                if (value <= 0) {
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Logarithm is only defined for positive numbers");
                }
                result = Math.log10 (value);
                break;
            case "ln":
                if (value <= 0) {
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Natural logarithm is only defined for positive numbers");
                }
                result = Math.log (value);
                break;
            case "sqrt":
                if (value < 0) {
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Square root is not defined for negative numbers");
                }
                result = Math.sqrt (value);
                break;
            case "abs":
                result = Math.fabs (value);
                break;
            case "ceil":
                result = Math.ceil (value);
                break;
            case "floor":
                result = Math.floor (value);
                break;
            case "round":
                result = Math.round (value);
                break;
            case "exp":
                result = Math.exp (value);
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown function: %s".printf (function));
        }
        
        // Create structured result using Variant
        var structured_data_builder = new VariantBuilder (new VariantType ("a{sv}"));
        structured_data_builder.add ("{sv}", "result", new Variant.double (result));
        structured_data_builder.add ("{sv}", "function", new Variant.string (function));
        structured_data_builder.add ("{sv}", "input", new Variant.double (value));
        if (degrees && (function == "sin" || function == "cos" || function == "tan")) {
            structured_data_builder.add ("{sv}", "degrees", new Variant.boolean (true));
            structured_data_builder.add ("{sv}", "expression", new Variant.string ("%s(%.2f°) = %.6f".printf (function, value, result)));
        } else {
            structured_data_builder.add ("{sv}", "expression", new Variant.string ("%s(%.2f) = %.6f".printf (function, value, result)));
        }
        
        var structured_data = structured_data_builder.end ();
        
        return create_structured_result ("Advanced calculation result: %.6f".printf (result), structured_data);
    }
}

/**
 * Unit converter tool for converting between different units.
 */
public class UnitConverterTool : Mcp.Tools.BaseExecutor {
    /**
     * Creates a new UnitConverterTool.
     */
    public UnitConverterTool () {
        // Create tool definition using Variant
        var builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Add schema properties
        builder.add ("{sv}", "type", new Variant.string ("object"));
        builder.add ("{sv}", "description", new Variant.string ("Convert between different units of measurement"));
        
        var properties_builder = new VariantBuilder (new VariantType ("a{sv}"));
        
        // Conversion type property
        var type_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        type_prop_builder.add ("{sv}", "type", new Variant.string ("string"));
        type_prop_builder.add ("{sv}", "description", new Variant.string ("Type of conversion"));
        
        var enum_array_builder = new VariantBuilder (new VariantType ("as"));
        enum_array_builder.add ("s", "temperature");
        enum_array_builder.add ("s", "length");
        enum_array_builder.add ("s", "weight");
        enum_array_builder.add ("s", "volume");
        enum_array_builder.add ("s", "data");
        type_prop_builder.add ("{sv}", "enum", enum_array_builder.end ());
        properties_builder.add ("{sv}", "type", type_prop_builder.end ());
        
        // From unit property
        var from_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        from_prop_builder.add ("{sv}", "type", new Variant.string ("string"));
        from_prop_builder.add ("{sv}", "description", new Variant.string ("Source unit"));
        properties_builder.add ("{sv}", "from", from_prop_builder.end ());
        
        // To unit property
        var to_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        to_prop_builder.add ("{sv}", "type", new Variant.string ("string"));
        to_prop_builder.add ("{sv}", "description", new Variant.string ("Target unit"));
        properties_builder.add ("{sv}", "to", to_prop_builder.end ());
        
        // Value property
        var value_prop_builder = new VariantBuilder (new VariantType ("a{sv}"));
        value_prop_builder.add ("{sv}", "type", new Variant.string ("number"));
        value_prop_builder.add ("{sv}", "description", new Variant.string ("Value to convert"));
        properties_builder.add ("{sv}", "value", value_prop_builder.end ());
        
        builder.add ("{sv}", "properties", properties_builder.end ());
        
        var required_array_builder = new VariantBuilder (new VariantType ("as"));
        required_array_builder.add ("s", "type");
        required_array_builder.add ("s", "from");
        required_array_builder.add ("s", "to");
        required_array_builder.add ("s", "value");
        builder.add ("{sv}", "required", required_array_builder.end ());
        
        var input_schema = builder.end ();
        
        var definition = new Mcp.Tools.Types.ToolDefinition ("unit_converter", input_schema);
        definition.title = "Unit Converter";
        definition.description = "Convert between different units of measurement (temperature, length, weight, volume, data)";
        
        base (definition);
    }
    
    /**
     * {@inheritDoc}
     */
    protected override async Mcp.Tools.Types.CallToolResult do_execute (GLib.Variant arguments) throws Error {
        string conversion_type = get_string_arg (arguments, "type");
        string from_unit = get_string_arg (arguments, "from");
        string to_unit = get_string_arg (arguments, "to");
        double value = get_double_arg (arguments, "value");
        
        double result = 0.0;
        
        try {
            switch (conversion_type) {
                case "temperature":
                    result = convert_temperature (value, from_unit, to_unit);
                    break;
                case "length":
                    result = convert_length (value, from_unit, to_unit);
                    break;
                case "weight":
                    result = convert_weight (value, from_unit, to_unit);
                    break;
                case "volume":
                    result = convert_volume (value, from_unit, to_unit);
                    break;
                case "data":
                    result = convert_data (value, from_unit, to_unit);
                    break;
                default:
                    throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown conversion type: %s".printf (conversion_type));
            }
        } catch (Error e) {
            throw new Mcp.Core.McpError.INVALID_PARAMS ("Conversion error: %s".printf (e.message));
        }
        
        // Create structured result using Variant
        var structured_data_builder = new VariantBuilder (new VariantType ("a{sv}"));
        structured_data_builder.add ("{sv}", "result", new Variant.double (result));
        structured_data_builder.add ("{sv}", "conversion_type", new Variant.string (conversion_type));
        structured_data_builder.add ("{sv}", "from_unit", new Variant.string (from_unit));
        structured_data_builder.add ("{sv}", "to_unit", new Variant.string (to_unit));
        structured_data_builder.add ("{sv}", "input_value", new Variant.double (value));
        structured_data_builder.add ("{sv}", "expression", new Variant.string ("%.2f %s = %.2f %s".printf (value, from_unit, result, to_unit)));
        
        var structured_data = structured_data_builder.end ();
        
        return create_structured_result ("Conversion result: %.2f %s".printf (result, to_unit), structured_data);
    }
    
    /**
     * Converts temperature between different units.
     */
    private double convert_temperature (double value, string from, string to) throws Error {
        // First convert to Celsius
        double celsius;
        switch (from.down ()) {
            case "c":
            case "celsius":
                celsius = value;
                break;
            case "f":
            case "fahrenheit":
                celsius = (value - 32) * 5 / 9;
                break;
            case "k":
            case "kelvin":
                celsius = value - 273.15;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown temperature unit: %s".printf (from));
        }
        
        // Then convert from Celsius to target unit
        switch (to.down ()) {
            case "c":
            case "celsius":
                return celsius;
            case "f":
            case "fahrenheit":
                return celsius * 9 / 5 + 32;
            case "k":
            case "kelvin":
                return celsius + 273.15;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown temperature unit: %s".printf (to));
        }
    }
    
    /**
     * Converts length between different units.
     */
    private double convert_length (double value, string from, string to) throws Error {
        // Convert to meters first
        double meters;
        switch (from.down ()) {
            case "m":
            case "meter":
            case "meters":
                meters = value;
                break;
            case "cm":
            case "centimeter":
            case "centimeters":
                meters = value / 100;
                break;
            case "km":
            case "kilometer":
            case "kilometers":
                meters = value * 1000;
                break;
            case "ft":
            case "foot":
            case "feet":
                meters = value * 0.3048;
                break;
            case "in":
            case "inch":
            case "inches":
                meters = value * 0.0254;
                break;
            case "mi":
            case "mile":
            case "miles":
                meters = value * 1609.34;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown length unit: %s".printf (from));
        }
        
        // Convert from meters to target unit
        switch (to.down ()) {
            case "m":
            case "meter":
            case "meters":
                return meters;
            case "cm":
            case "centimeter":
            case "centimeters":
                return meters * 100;
            case "km":
            case "kilometer":
            case "kilometers":
                return meters / 1000;
            case "ft":
            case "foot":
            case "feet":
                return meters / 0.3048;
            case "in":
            case "inch":
            case "inches":
                return meters / 0.0254;
            case "mi":
            case "mile":
            case "miles":
                return meters / 1609.34;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown length unit: %s".printf (to));
        }
    }
    
    /**
     * Converts weight between different units.
     */
    private double convert_weight (double value, string from, string to) throws Error {
        // Convert to kilograms first
        double kilograms;
        switch (from.down ()) {
            case "kg":
            case "kilogram":
            case "kilograms":
                kilograms = value;
                break;
            case "g":
            case "gram":
            case "grams":
                kilograms = value / 1000;
                break;
            case "lb":
            case "pound":
            case "pounds":
                kilograms = value * 0.453592;
                break;
            case "oz":
            case "ounce":
            case "ounces":
                kilograms = value * 0.0283495;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown weight unit: %s".printf (from));
        }
        
        // Convert from kilograms to target unit
        switch (to.down ()) {
            case "kg":
            case "kilogram":
            case "kilograms":
                return kilograms;
            case "g":
            case "gram":
            case "grams":
                return kilograms * 1000;
            case "lb":
            case "pound":
            case "pounds":
                return kilograms / 0.453592;
            case "oz":
            case "ounce":
            case "ounces":
                return kilograms / 0.0283495;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown weight unit: %s".printf (to));
        }
    }
    
    /**
     * Converts volume between different units.
     */
    private double convert_volume (double value, string from, string to) throws Error {
        // Convert to liters first
        double liters;
        switch (from.down ()) {
            case "l":
            case "liter":
            case "liters":
                liters = value;
                break;
            case "ml":
            case "milliliter":
            case "milliliters":
                liters = value / 1000;
                break;
            case "gal":
            case "gallon":
            case "gallons":
                liters = value * 3.78541;
                break;
            case "qt":
            case "quart":
            case "quarts":
                liters = value * 0.946353;
                break;
            case "pt":
            case "pint":
            case "pints":
                liters = value * 0.473176;
                break;
            case "cup":
            case "cups":
                liters = value * 0.236588;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown volume unit: %s".printf (from));
        }
        
        // Convert from liters to target unit
        switch (to.down ()) {
            case "l":
            case "liter":
            case "liters":
                return liters;
            case "ml":
            case "milliliter":
            case "milliliters":
                return liters * 1000;
            case "gal":
            case "gallon":
            case "gallons":
                return liters / 3.78541;
            case "qt":
            case "quart":
            case "quarts":
                return liters / 0.946353;
            case "pt":
            case "pint":
            case "pints":
                return liters / 0.473176;
            case "cup":
            case "cups":
                return liters / 0.236588;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown volume unit: %s".printf (to));
        }
    }
    
    /**
     * Converts data storage between different units.
     */
    private double convert_data (double value, string from, string to) throws Error {
        // Convert to bytes first
        double bytes;
        switch (from.down ()) {
            case "b":
            case "byte":
            case "bytes":
                bytes = value;
                break;
            case "kb":
            case "kilobyte":
            case "kilobytes":
                bytes = value * 1024;
                break;
            case "mb":
            case "megabyte":
            case "megabytes":
                bytes = value * 1024 * 1024;
                break;
            case "gb":
            case "gigabyte":
            case "gigabytes":
                bytes = value * 1024 * 1024 * 1024;
                break;
            case "tb":
            case "terabyte":
            case "terabytes":
                bytes = value * 1024.0 * 1024.0 * 1024.0 * 1024.0;
                break;
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown data unit: %s".printf (from));
        }
        
        // Convert from bytes to target unit
        switch (to.down ()) {
            case "b":
            case "byte":
            case "bytes":
                return bytes;
            case "kb":
            case "kilobyte":
            case "kilobytes":
                return bytes / 1024;
            case "mb":
            case "megabyte":
            case "megabytes":
                return bytes / (1024 * 1024);
            case "gb":
            case "gigabyte":
            case "gigabytes":
                return bytes / (1024 * 1024 * 1024);
            case "tb":
            case "terabyte":
            case "terabytes":
                return bytes / (1024.0 * 1024.0 * 1024.0 * 1024.0);
            default:
                throw new Mcp.Core.McpError.INVALID_PARAMS ("Unknown data unit: %s".printf (to));
        }
    }
}

/**
 * Main function.
 *
 * @param args Command line arguments
 * @return Exit code
 */
public static int main (string[] args) {
    // Create and run the server
    var server = new CalculatorServer ();
    
    // Handle Ctrl+C to gracefully shutdown
    // For now, we'll skip signal handling to get the build working
    
    var loop = new MainLoop ();
    
    // Run the server
    server.run.begin ((obj, res) => {
        loop.quit ();
    });
    
    // Keep the main loop running
    loop.run ();
    
    return 0;
}