ASP Runtime Library

Babel supports ASP and WScript clients. The following files are deployed for ASP:

• inc_json2_func.asp
• inc_babel.asp
• errorModel.asp

And, for WScript:

• inc_json2_func.js
• inc_babel.vbs
• errorModel.vbs

Do not edit inc_json2_func.asp or inc_babel.asp!!!

These files are considered part of the Babel deployment - don't modify them directly because the changes need to be incorporated into the distribution. As a reminder, the files include this header:

' *** WARNING: This code is generated by a tool and deployed with BABEL. ***
' *** Please see the Babel Team if you believe it needs changes.         ***

For ASP, you only need to include inc_babel.asp:

<!--#include file="../Scripts/inc_babel.asp"-->

For WScript, you'll need to include all three in your WScript (.wsf) file:

<script language="VBScript" src="..\includes\errorModel.vbs" />
<script language="JavaScript" src="..\includes\inc_json2_func.js" />
<script language="VBScript" src="..\includes\inc_babel.vbs" />

Code Generation

Babel has additional options to specificy the kind of file to generate:

babel -lang asp -output dir -options ext=vbs file.babel

The ext options can be set to vbs or asp, and defaults to asp.

Babel will generate model files and client files. The models include VBScript classes for each struct, as well as constants defined for const and enum declarations. There are helper functions to convert between the enumeration's string value and integer value.

Generated files have the following header as a reminder not to touch them:

' AUTO-GENERATED FILE - DO NOT MODIFY
' Generated from dir/somefile.babel

Using the Babel Client

A client is a generated VBScript class that you can easily create and initialize with the base URL and timeout for the service:

dim client : set client = new CoolClient
call client.InitHttp("http://localhost/CoolService", 30)

If needed, HTTP headers can be set:

call client.SetHeader("UserId", 4)

Methods on the client class can now be invoked to use the client.

Notes on calling conventions

Because VBScript has the set keyword, it can be a little confusing to figure out how to call a method.

Babel Method Definition	VBScript Return Type	Example
void SayHello();	None	call client.SayHello()
string GetData();	String	dim s : s = client.GetData()
list<string> GetData();	Array	dim arr : arr = client.GetData()
map<string, string> GetData();	Scripting.Dictionary	dim obj : set obj = client.GetData()
MyStruct GetData();	Object	dim obj : set obj = client.GetData() if not obj is nothing then ' do something end if

Babel tries to ensure that lists and maps will always be returned as non-null.

Models

Models are implemented as VBScript classes. Each model will have the following methods:

• Class_Initialize - constructor
• Class_Terminate - destructor
• Write - internal function for writing the object to the stream
• Read - internal function for reading the object from the stream
• ToJSON - convert to a JSON string (Babel format)
• ToXML - convert to an XML document (USE WITH CAUTION!! this format is ever-changing as Babel does not officially support XML)

A Babel list is implemented as a VBScript array. A map is implemented as a Scripting.Dictionary object. Lists and maps are initialized in Class_Initialize, so it's safe to assume they exist.

A null value for a primitive type (and enumerations) is equivalent to the VBScript empty keyword. Where possible, Babel's VBScript code tries to treat the VBScript null keyword the same way, but in reality VBScript uses this for database values.

A null value for a struct type is represented as nothing in VBScript. nothing is for objects; empty is for non-objects.