16.6.4.4 Querying switches interactively

Another solution to query the arguments for the tool is to ask the user interactively. The scripting languages provides a number of solutions for these.

They generally have their own native way to read input, possibly by creating a dialog.

In addition, the simplest solution is to use the predefined GPS commands for this. These are the two functions:

yes_no_dialog

This function takes a single argument, which is a question to display. Two buttons are then available to the user, "Yes" and "No". The result of this function is the button the user has selected, as a boolean value.

input_dialog

This function is more general. It takes a minimum of two arguments, with no upper limit. The first argument is a message describing what input is expected from the user. The second, third and following arguments each correspond to an entry line in the dialog, to query one specific value (as a string). The result of this function is a list of strings, each corresponding to these arguments.

From the GPS shell, it is only convenient to query one value at a time, since it doesn't have support for lists, and would return a concatenation of the values. However, this function is especially useful with other scripting languages.

The following is a short example that queries the name of a directory and a file name, and displays each in the Messages window.

     <?xml version="1.0" ?>
     <query_file>
       <action name="query file and dir">
         <shell lang="python">list=GPS.MDI.input_dialog \
           ("Please enter directory and file name", "Directory", "File")</shell>
         <shell lang="python">print ("Dir=" + list[0], "File=" + list[1])</shell>
         </shell>
       </action>
     </query_file>