If you are using the Replace String command, and wish to replace the letter "x" with the letter "X" and your code looks something like:
$text:="This is x a small letter"
$text:=Replace String($text;$CAPITAL;"A") ` NOT what we want
$text:=Replace String($text;$lower_case;"A") ` what we want
This code will not work, because the Replace String command is NOT case sensitive. Therefore since the Replace String command is NOT a case sensitive, the only way to compare "x" to "X" is by comparing their ASCII values. Here is sample code that will solve the problem above.
$text:="this is the answer: X"
NOTE: In 4D, comparisons are not case sensitive.