It makes for convenient shorthand. You can also use the with statement with objectModels and table addresses, but that is beyond the scope of this tutorial. In line 15 we make sure that the argTable exists using the defined verb. In lines 16 thru 34 a for loop walks through all the parameters in the information list and puts them into local variables. Note the use of the case statement in lines 18 to 31.
Case statements are wonderful for looking at a list of items.
This is done to allow error checking and to make sure all the variables exist. If one of the variables on the information list is missing, lines 33 and 34 check the req list and if it is a required variable, send back an error message explaining that the variable is required. Lines 35 and 36 only execute if the argTable is not defined. This may happen if a bad form calls this CGI script and does not send parameters. The rest of the script calls other functions to do the actual processing.