Using Libraries

If you have a set of functions that you want to use in more than one script, you should save the functions in a separate library file. A library file is simply a standard script file (.dsb) that you load into another script when it is first opened.

For example, assume you want to modify the example Decision Tree.dsb so that it displays a progress bar on each page. That is, change a typical page from this

to this

Decision tree scripts use the primitive choose to display options to the user. You can insert a progress bar on each page by redefining choose in a library file and including this file in the original decision tree script.

First you must open a blank script and enter a new definition for choose.

choose(query:=dialogtemplate):=
@choose(ProgressBar+query)

The first argument passed to choose is the text that will be displayed (query). Normally you do not supply any arguments with choose. Instead, the display text is found in the Form Window. You accomplish this by making the first argument optional with a default value of dialogtemplate. All the new definition of choose does is precede the usual query with a progress bar and then call the primitive version of choose. You call primitives explicitly using the @ operator.

The definition for ProgressBar is as follows:

ProgressBar():={
var pct=user(floor(StepsDone++/TotalSteps*100));
"<div align=\"right\">
<table border=\"1\" cellpadding=\"0\
cellspacing=\"1\" width=\"100\">
<tr><td width=\""+(pct+1)+"\" bgcolor=\"#0000FF\">
<font size=\"1\">&nbsp;</font></td><td></td></tr>
</table>"+pct+"% Done</div>";
}

This definition calculates the percent done from two variables (StepsDone and TotalSteps) and generates a small HTML table that looks like a progress bar.

Once you have entered a definition for choose and ProgressBar, save the file using the name choose.dsb (any name will do).

To use the new definition of choose in the original decision tree script, open the script and click Tools, Script Options, Include library files.

This opens a dialog box where you list all library files you want to include in your script.

Finally, you must modify the script slightly because the new choose function expects there to be definitions for StepsDone and TotalSteps in your script. Change the root definition from

Root:=branch(choose,Ins1,Ins2)

to

Root:=(
var TotalSteps=4,StepsDone=0;
branch(choose,Ins1,Ins2);
)

Now you are done. You will notice that the decision tree script does not look any different except for the change to Root. The new choose function is used just like the original primitive. Also, if you decide to change the way progress bars are displayed, all you need to change is the file choose.dsb. Every script that uses this library file will change automatically.

Library files can be placed in either the program directory or the script directory. If you place a library file in the directory where the server is located (usually C:\Program Files\Vanguard\Dscript Server 4\Decision) then the library file is available to all scripts. If you place the library file in the directory where the script is located, then only scripts in that directory can access the library file.