Automated Argument Validation

Windows Script Host (WSH) provides two useful but potentially confusing tools for working with command-line arguments: the WshArguments object, which lets scripters easily read supplied arguments and their types and values, and (specifically in Windows Script File—.wsf—files) the XML <runtime> element, which automates Help text generation. (A .wsf file uses an XML structure to add helper elements to a script; for easy identification, I refer to these helper elements by their tag names, which are simply the element names enclosed in the angle brackets—<>—used to delimit tags.) It's easy to confuse these tools' characteristics. Scripters often assume that the <runtime> element's <named> and <unnamed> elements validate user-supplied arguments, when in reality these elements simply give you nicely formatted Help text. As Bob Wells discusses in "Rem: Relating the WSH 5.6 <named> Element to Mandatory Arguments," October 2002, InstantDoc ID 26363, the elements don't validate user-supplied arguments. In other words, even though the <named> and <unnamed> elements in a .wsf script explicitly describe argument constraints (e.g., what's required, what's optional, what kind of values arguments should have, the number of arguments), you have to write the code to validate those arguments. . . .