Exercise 3: Improve Data Entry Routine

1. Start Studio, and open the mydatent routine.

2. Write the $$validName user-defined function.

   validName(name) PUBLIC ; validate a Name
       /* returns 0 for an invalid name and writes error message
          returns the unchanged name otherwise */
       {
       if (name?1u.l1","1u.l) {
           quit name }
       else {
           write !,"Last,First"
           quit 0
          }
       }

   

3. Write the $$validPhone user-defined function. After verifying the phone number, add the default area code if necessary.

   validPhone(phone) PUBLIC ; validate a phone number
       /* returns 0 for invalid phone numbers and writes error message
          returns the valid phone number with default area code added 
          if necessary */
       {
       if (phone?.1(3n1"-")3n1"-"4n) {
           set:(phone?3n1"-"4n) phone = "617-" _ phone ; add default area code
           quit phone
          }
       else {
           write !, "###-###-#### or ###-####"
           quit 0
          }
       }

   

4. Write the $$validDOB user-defined function. Make sure you disallow future dates.

   validDOB(date) PUBLIC ; validate a Date of Birth
       /* returns 0 for invalid dates and writes error message
          returns internal format for valid dates */
       {
       set convdate = $zdateh( date, 5,,,,,,, -1)
       if (convdate = -1) {
           write !,"Date in the past"
           quit 0 ; invalid date
          }
       elseif (convdate > $piece( $horolog, ",", 1)) {
           write !,"Date in the past"
           quit 0 ; invalid because it's in the future
          }
       else {
           quit convdate ; valid date
          }
       }

   

5. Edit the prompt procedure. Use Do/While to cause prompts to repeat until the data is correct, using the three new “$$valid” user-defined functions.

   prompt() [name, phone, intdob]
     ; procedure for prompting
     {
       do {
           read !, "Name: ", name
           quit:(name = "")  ; user entered nothing
           set name = $$validName( name )
       }
       while name = 0
       quit:(name = "")  ; exit procedure
   
       do {
           read !, "Phone (617): ", phone
           set phone = $$validPhone( phone )
       }
       while phone = 0
   
       do {
           read !, "DOB: ", dob
           set intdob = $$validDOB( dob )
       }
       while intdob = 0
       write !!
     }

   

6. Edit the display procedure. Add code to convert the date to the external format you like best.

   display() [name, phone, intdob]
       ; display the data
       {
       write !, "Name:", ?20, name
       write !, "Phone:", ?20, phone
       write !, "DOB:", ?20, $zdate( intdob, 2)
       write !!
       }