Unity-MCP

using System; using System.Collections.Generic; using System.Text; using UnityEngine; namespace UnityMCP.Client.Editor.Commands { /// <summary> /// Parser for expressions like find("objectName").propertyName /// </summary> public class ExpressionParser { private readonly string _expression; private int _position; /// <summary> /// Create a new ExpressionParser /// </summary> /// <param name="expression">The expression to parse</param> public ExpressionParser(string expression) { _expression = expression; _position = 0; } /// <summary> /// Parse the expression into a command /// </summary> /// <returns>The command to execute</returns> public ICommand Parse() { try { // Parse the primary expression ICommand command = ParsePrimary(); // Parse any property accesses while (_position < _expression.Length && _expression[_position] == '.') { // Skip the '.' _position++; // Parse the property name string propertyName = ParseIdentifier(); // Create a temporary variable name for the result of the previous command string tempVariableName = "_temp_" + Guid.NewGuid().ToString("N").Substring(0, 8); // Set the result variable name for the previous command if (command is CommandBase commandBase) { // We can't set the ResultVariableName property directly because it's read-only // Instead, we'll create a new property command that references the result command = new PropertyCommand(tempVariableName, propertyName); } } return command; } catch (Exception ex) { Debug.LogError($"[Unity MCP] Error parsing expression: {ex.Message}"); return new GenericCommand(_expression); } } /// <summary> /// Parse a primary expression /// </summary> /// <returns>The command to execute</returns> private ICommand ParsePrimary() { // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length) { throw new Exception("Unexpected end of expression"); } // Check if it's a find expression if (_position + 4 < _expression.Length && _expression.Substring(_position, 4) == "find") { return ParseFind(); } // Check if it's a new GameObject expression if (_position + 3 < _expression.Length && _expression.Substring(_position, 3) == "new") { return ParseNewGameObject(); } // Check if it's a Debug.Log expression if (_position + 9 < _expression.Length && _expression.Substring(_position, 9) == "Debug.Log") { return ParseDebugLog(); } // If we couldn't parse the primary expression, return a generic command return new GenericCommand(_expression); } /// <summary> /// Parse a find expression /// </summary> /// <returns>The command to execute</returns> private ICommand ParseFind() { // Skip 'find' _position += 4; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != '(') { throw new Exception("Expected '(' after 'find'"); } // Skip '(' _position++; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != '\"') { throw new Exception("Expected string literal for GameObject name"); } // Parse the string literal string gameObjectName = ParseStringLiteral(); // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != ')') { throw new Exception("Expected ')' after GameObject name"); } // Skip ')' _position++; // Create a find command return new FindGameObjectCommand(gameObjectName); } /// <summary> /// Parse a new GameObject expression /// </summary> /// <returns>The command to execute</returns> private ICommand ParseNewGameObject() { // Skip 'new' _position += 3; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position + 10 >= _expression.Length || _expression.Substring(_position, 10) != "GameObject") { throw new Exception("Expected 'GameObject' after 'new'"); } // Skip 'GameObject' _position += 10; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != '(') { throw new Exception("Expected '(' after 'GameObject'"); } // Skip '(' _position++; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length) { throw new Exception("Unexpected end of expression"); } // Parse the parameters string parameters = ""; if (_expression[_position] == '\"') { // Parse the string literal parameters = ParseStringLiteral(); } else { // Parse until ')' int start = _position; while (_position < _expression.Length && _expression[_position] != ')') { _position++; } parameters = _expression.Substring(start, _position - start); } // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != ')') { throw new Exception("Expected ')' after GameObject parameters"); } // Skip ')' _position++; // Create a create GameObject command return new CreateGameObjectCommand($"new GameObject({parameters})"); } /// <summary> /// Parse a Debug.Log expression /// </summary> /// <returns>The command to execute</returns> private ICommand ParseDebugLog() { // Skip 'Debug.Log' _position += 9; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != '(') { throw new Exception("Expected '(' after 'Debug.Log'"); } // Skip '(' _position++; // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length) { throw new Exception("Unexpected end of expression"); } // Parse the message string message = ""; if (_expression[_position] == '\"') { // Parse the string literal message = ParseStringLiteral(); } else { // Parse until ')' int start = _position; while (_position < _expression.Length && _expression[_position] != ')') { _position++; } message = _expression.Substring(start, _position - start); } // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length || _expression[_position] != ')') { throw new Exception("Expected ')' after Debug.Log message"); } // Skip ')' _position++; // Create a log command return new LogCommand($"Debug.Log({message})"); } /// <summary> /// Parse a string literal /// </summary> /// <returns>The string literal</returns> private string ParseStringLiteral() { // Skip the opening quote _position++; // Parse until the closing quote int start = _position; while (_position < _expression.Length && _expression[_position] != '\"') { // Handle escape sequences if (_expression[_position] == '\\' && _position + 1 < _expression.Length) { _position += 2; } else { _position++; } } // Get the string literal string stringLiteral = _expression.Substring(start, _position - start); // Skip the closing quote if (_position < _expression.Length) { _position++; } return stringLiteral; } /// <summary> /// Parse an identifier /// </summary> /// <returns>The identifier</returns> private string ParseIdentifier() { // Skip whitespace SkipWhitespace(); // Check if we're at the end of the expression if (_position >= _expression.Length) { throw new Exception("Unexpected end of expression"); } // Check if it's a valid identifier start if (!char.IsLetter(_expression[_position]) && _expression[_position] != '_') { throw new Exception($"Expected identifier, got '{_expression[_position]}'"); } // Parse the identifier int start = _position; while (_position < _expression.Length && (char.IsLetterOrDigit(_expression[_position]) || _expression[_position] == '_')) { _position++; } return _expression.Substring(start, _position - start); } /// <summary> /// Skip whitespace /// </summary> private void SkipWhitespace() { while (_position < _expression.Length && char.IsWhiteSpace(_expression[_position])) { _position++; } } } }