Returns TRUE if a series is at its tail.
empty? series
series - The series argument. (must be: series port bitset)
This is a synonym for TAIL? The check is made relative to the current location in the series.
print empty? [] true
print empty? [1] false
The EMPTY? function is useful for all types of series. For instance, you can use it to check a string returned from the user:
str: ask "Enter name:" if empty? str [print "Name is required"] Enter name:
It is often used in conjunction with TRIM to remove black spaces from the ends of a string before checking it:
if empty? trim str [print "Name is required"]
found? - Returns TRUE if value is not NONE.
none? - Returns TRUE for none values.
tail? - Returns TRUE if a series is at its tail.