#Script debugger microsoft windows#

In addition, the Active Scripting specification also defines a contract (a set of COM interfaces, again) for debuggers to take advantage of the host in their operations. There are also third-party Active Scripting engines to support other script languages, including Perl and Python.

#Script debugger microsoft windows#

Examples of Active Scripting hosts include the Internet Information Services (IIS) web server (server-side scripts embedded in ASP or ASP.NET pages), Internet Explorer (client-side script hosting in web pages), and the Windows scripting hosts ( cscript.exe or wscript.exe) that ship with Windows and can be used to host scripts executed from a command prompt. Examples of Active Scripting engines are vbscript.dll and jscript.dll, which both ship with Windows under the system32 directory. The Active Scripting specification defines a language-processing engine, with the Active Scripting host using that engine when the script needs to be interpreted. In Windows, both VBScript and JScript (Microsoft’s implementation of JavaScript) are Active Scripting languages whose implementation fully conforms with that specification. This specification was introduced by Microsoft in the 90s and defines a set of COM interfaces to allow script languages that implement them to be hosted in any conforming host application.

The key to that architecture is the Active Scripting specification. To understand how script debugging works, it’s useful to first explain a few basic concepts about how script languages are executed in Windows. In both cases, the debugger needs the script host’s or the CLR execution engine’s collaboration to support source-level debugging of the target process.

One of the reasons that the CLR used the in-process debugging model when it was first released to the public in 2002 was that script debugging had been successfully using it for years (since the mid-90s). This is internally implemented using the same in-process paradigm that managed-code debugging relies on.

Visual Studio also supports source-level debugging of script languages such as VBScript or JScript.