scripter.hpp

OSB-PIK-OpenVXI-3.0.0源代码 “中国XML论坛 - 专业的XML技术讨论区--XML在语音技术中的应用”

 /****************License************************************************
  *
  * Copyright 2000-2003.  ScanSoft, Inc.    
  *
  * Use of this software is subject to notices and obligations set forth 
  * in the SpeechWorks Public License - Software Version 1.2 which is 
  * included with this software. 
  *
  * ScanSoft is a registered trademark of ScanSoft, Inc., and OpenSpeech, 
  * SpeechWorks and the SpeechWorks logo are registered trademarks or 
  * trademarks of SpeechWorks International, Inc. in the United States 
  * and other countries.
  *
  ***********************************************************************/
 
/***********************************************************************
  *
  * ECMA Script evaluation engine
  *
  * Using the VXIjsi interface, this layer is employed by the VoiceXML 
  * Interpreter to set and retrieve script variables and evaluate expressions.
  *
  ***********************************************************************/
 
 #ifndef _EXE_CONT
 #define _EXE_CONT
 
 #include "VXIvalue.h"
 #include <vector>
 #include <string>
 
 extern "C" struct VXIjsiInterface;
 extern "C" struct VXIjsiContext;
 
 typedef std::basic_string<VXIchar> vxistring;
 
 class Scripter {
   // All functions, except the destructor, may throw exceptions.  These fall
   // into two classes.   The interpreter events represent semantic errors
   // which could in principal be handled by the application.  And the severe
   // JavaScriptErrors indicate serious errors with the VXIjsi layer.
   //
   //    VXIException::InterpreterEvent(EV_ERROR_ECMASCRIPT)
   //    VXIException::JavaScriptError();
 
 public:
   Scripter(VXIjsiInterface* jsiapi);
   ~Scripter();
 
   bool IsVarDefined(const vxistring & name);
   // Determines whether or not the named variable is defined.
   //
   // Returns: true if variable has been defined
   //          false otherwise
 
   bool IsVarDeclared(const vxistring & name);
   // Determines whether or not the named variable is declared.
   //
   // Returns: true if variable has been declared
   //          false otherwise
 
   void MakeVar(const vxistring & name, const vxistring & expr);
   void MakeVar(const vxistring & name, const VXIValue * value);
   // Creates a new variablevariable to the indicated expression.
 
   void SetVar(const vxistring & name, const vxistring & expr);
   // Sets an existing variable to the indicated expression.
 
   void SetVarReadOnly(const vxistring & name);
 
   void ClearVar(const vxistring & name);
   // Sets a variable to 'undefined'.
 
   void SetString(const vxistring & var, const vxistring & val);
   // Creates a new variable or sets an existing variable to the indicated
   // string.
 
   void SetValue(const vxistring & var, const VXIValue * value);
   // Creates a new variable or sets an existing variable to the indicated
   // value type.  This may be used for complex types such as Object.
 
   VXIValue* GetValue(const vxistring & name) const;
   // Retrieves a variable from ECMAScript.  The conversion is as follows:
   //
   //   Undefined, Null       --> NULL pointer
   //   String                --> VXIString
   //   Boolean               --> VXIFloat or VXIInteger {true, false} -> {1, 0}
   //   Number                --> VXIFloat or VXIInteger
   //   Object                --> VXIMap
   //
   // NOTE: The caller must free the resulting VXIValue.
 
   void PushScope(const vxistring & name, bool alias = false);
   // Pushes a new variable scope onto the stack with the given name.  New
   // variables will be defined in this scope, unless they are explicitly
   // referenced using <scope>.<variable_name> as in application.lastresult$.
 
   void PopScope();
   // Pops the current scope, destroying it and any associated variables.
 
   bool CurrentScope(const vxistring & name) const;
   // Checks the name of the current scope against the argument.
   //
   // Returns: true if the current scope matches the requested name.
   //          false otherwise
 
   void EvalScript(const vxistring & script);
   // Simply evaluates an ECMAScript script and returns nothing.
 
   VXIint EvalScriptToInt(const vxistring & script);
   // Evaluates an ECMAScript script, and converts the result to an integer.
 
   void EvalScriptToString(const vxistring & script, vxistring & result);
   // Evaluates an ECMAScript script, and converts the result to a string.
 
   VXIValue * EvalScriptToValue(const vxistring & script);
   // Evaluates an ECMAScript script, and converts the result to a string.
   // NOTE: The caller must free the resulting VXIValue.
 
   bool TestCondition(const vxistring & script);
   // Evaluates an expression as a boolean.
 
 private:
   void maybe_throw_js_error(int err) const;
 
   Scripter(const Scripter &);                 // no implementation
   Scripter & operator=(const Scripter &);     // no implementation
 
 private:
   typedef std::vector<vxistring> SCOPESTACK;
   SCOPESTACK scopeStack;
 
   VXIjsiInterface * jsi_api;
   VXIjsiContext * jsi_context;
 };
 
 #endif