ChaiScript/include/chaiscript/language/chaiscript_common.hpp

// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2011, Jonathan Turner (jonathan@emptycrate.com)
// and Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com

#ifndef CHAISCRIPT_COMMON_HPP_
#define	CHAISCRIPT_COMMON_HPP_

#include <chaiscript/dispatchkit/dispatchkit.hpp>
#include <boost/enable_shared_from_this.hpp>

namespace chaiscript
{
  typedef ModulePtr (*Create_Module_Func)();

  /**
   * Types of AST nodes available to the parser and eval
   */
  class AST_Node_Type {
  public:
    enum Type { Error, Int, Float, Id, Char, Str, Eol, Fun_Call, Inplace_Fun_Call, Arg_List, Variable, Equation, Var_Decl,
                Comparison, Additive, Multiplicative, Array_Call, Dot_Access, Quoted_String, Single_Quoted_String,
                Lambda, Block, Def, While, If, For, Inline_Array, Inline_Map, Return, File, Prefix, Break, Map_Pair, Value_Range,
                Inline_Range, Annotation, Try, Catch, Finally, Method, Attr_Decl, Shift, Equality, Bitwise_And, Bitwise_Xor, Bitwise_Or, 
                Logical_And, Logical_Or
    };
  };

  namespace
  {
    /**
     * Helper lookup to get the name of each node type
     */
    const char *ast_node_type_to_string(int ast_node_type) {
      const char *ast_node_types[] = { "Internal Parser Error", "Int", "Float", "Id", "Char", "Str", "Eol", "Fun_Call", "Inplace_Fun_Call", "Arg_List", "Variable", "Equation", "Var_Decl",
                                    "Comparison", "Additive", "Multiplicative", "Array_Call", "Dot_Access", "Quoted_String", "Single_Quoted_String",
                                    "Lambda", "Block", "Def", "While", "If", "For", "Inline_Array", "Inline_Map", "Return", "File", "Prefix", "Break", "Map_Pair", "Value_Range",
                                    "Inline_Range", "Annotation", "Try", "Catch", "Finally", "Method", "Attr_Decl", "Shift", "Equality", "Bitwise_And", "Bitwise_Xor", "Bitwise_Or", 
                                    "Logical_And", "Logical_Or"};

      return ast_node_types[ast_node_type];
    }
  }

  /**
   * Convenience type for file positions
   */
  struct File_Position {
    int line;
    int column;

    File_Position(int t_file_line, int t_file_column)
      : line(t_file_line), column(t_file_column) { }

    File_Position() : line(0), column(0) { }
  };

  typedef boost::shared_ptr<struct AST_Node> AST_NodePtr;

  namespace exception
  {
    /**
     * Errors generated during parsing or evaluation
     */
    struct eval_error : public std::runtime_error {
      std::string reason;
      File_Position start_position;
      File_Position end_position;
      std::string filename;
      std::vector<AST_NodePtr> call_stack;

      eval_error(const std::string &t_why, const File_Position &t_where, const std::string &t_fname) throw() :
        std::runtime_error("Error: \"" + t_why + "\" " +
            (t_fname != "__EVAL__" ? ("in '" + t_fname + "' ") : "during evaluation ") +
            + "at (" + boost::lexical_cast<std::string>(t_where.line) + ", " +
            boost::lexical_cast<std::string>(t_where.column) + ")"),
        reason(t_why), start_position(t_where), end_position(t_where), filename(t_fname)
        { }

      eval_error(const std::string &t_why) throw()
        : std::runtime_error("Error: \"" + t_why + "\" "),
        reason(t_why) 
      {}

      virtual ~eval_error() throw() {}
    };

    /**
     * Errors generated when loading a file
     */
    struct file_not_found_error : public std::runtime_error {
      file_not_found_error(const std::string &t_filename) throw()
        : std::runtime_error("File Not Found: " + t_filename)
      { }

      virtual ~file_not_found_error() throw() {}
    };

  }

  /**
   * The struct that doubles as both a parser ast_node and an AST node
   */
  struct AST_Node : boost::enable_shared_from_this<AST_Node> {
    public:
      const std::string text;
      const int identifier;
      boost::shared_ptr<const std::string> filename;
      File_Position start, end;
      std::vector<AST_NodePtr> children;
      AST_NodePtr annotation;

      /**
       * Prints the contents of an AST node, including its children, recursively
       */
      std::string to_string(std::string t_prepend = "") {
        std::ostringstream oss;

        oss << t_prepend << "(" << ast_node_type_to_string(this->identifier) << ") "
            << this->text << " : " << this->start.line << ", " << this->start.column << std::endl;
        
        for (unsigned int j = 0; j < this->children.size(); ++j) {
          oss << this->children[j]->to_string(t_prepend + "  ");
        }
        return oss.str();
      }

      std::string internal_to_string() {
        return to_string();
      }

      Boxed_Value eval(chaiscript::detail::Dispatch_Engine &t_e) 
      {
        try {
          return eval_internal(t_e);
        } catch (exception::eval_error &ee) {
          ee.call_stack.push_back(shared_from_this());
          throw ee;
        }
      }


      void replace_child(const AST_NodePtr &t_child, const AST_NodePtr &t_new_child)
      {
        std::replace(children.begin(), children.end(), t_child, t_new_child);
      }

    protected:
      AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname, 
          int t_start_line, int t_start_col, int t_end_line, int t_end_col) :
        text(t_ast_node_text), identifier(t_id), filename(t_fname),
        start(t_start_line, t_start_col), end(t_end_line, t_end_col)
      {
      }

      AST_Node(const std::string &t_ast_node_text, int t_id, const boost::shared_ptr<std::string> &t_fname) :
        text(t_ast_node_text), identifier(t_id), filename(t_fname) {}

      virtual ~AST_Node() {}

      virtual Boxed_Value eval_internal(chaiscript::detail::Dispatch_Engine &)
      {
        throw std::runtime_error("Undispatched ast_node (internal error)");
      }
  };


  


  namespace detail
  {
    /**
     * Special type for returned values
     */
    struct Return_Value {
      Boxed_Value retval;

      Return_Value(const Boxed_Value &t_return_value) : retval(t_return_value) { }
    };

    /**
     * Special type indicating a call to 'break'
     */
    struct Break_Loop {
      Break_Loop() { }
    };

    /// Creates a new scope then pops it on destruction
    struct Scope_Push_Pop
    {
      Scope_Push_Pop(chaiscript::detail::Dispatch_Engine &t_de)
        : m_de(t_de)
      {
        m_de.new_scope();
      }

      ~Scope_Push_Pop()
      {
        m_de.pop_scope();
      }


      private:
        chaiscript::detail::Dispatch_Engine &m_de;
    };

  }
}

#endif	/* _CHAISCRIPT_COMMON_HPP */