March 7, 2004

DISPLAY and MOVE in SQR

DISPLAY and MOVE are two of the most commonly used commands in SQR. My recommendation: Don't use them.

DISPLAY is used to write information to the log, generally for tracing or error notification purposes. It works just fine, but it's limiting. To display a number in a specified format, you would need to code the following:

  let $amount = edit(#amount, '999,999.00')
  display 'Amount = ' noline
  display $amount

So what's the alternative? Use SHOW:

  show 'Amount = ' #amount edit '999,999.00'

DISPLAY handles one variable or literal at a time. It can do very limited formatting. SHOW, on the other hand, can use all of the capabilities of EDIT, can write many variables and/or literals at once, and can even position the cursor.

The situation is similar with MOVE. MOVE can take one variable or literal and assign it to a variable. The alternative, LET, is far more flexible. It can use functions (including EDIT()) and calculations. Instead of:

  move 1 to #sum
  add 1 to #sum

we can say:

  let #sum = 1 + 1

There is one oddity: If your variable contains an embedded "$" or "#" in its name, LET won't work:

  let $account# = '123' ! Error
  move '123' to $account# ! OK

Avoid this by keeping "$" and "#" out of your variable names (except, of course, as the first character).

Avoid the old COBOL-like commands in favor of the more flexible alternatives, and your code will not only be easier to write, but also cleaner and easier to read.

Until next time...