This function returns a string of $length spaces. If $length:

• is empty, an empty sequence is returned.
• is an integer, or castable to an integer, a string of that length is returned. If the length is negative, an empty sequence is returned.
• is anything else, the length of the string value of $length is used as the length.

In other words:

• f:spaces(()) is ‘()’,
• f:spaces(0) is ‘’ (no spaces),
• f:spaces(-1) is ‘()’,
• f:spaces(2) is ‘  ’ (two spaces),
• f:spaces("1") is ‘ ’ (one space), and
• f:spaces("test") is ‘    ’ (four spaces).

This function accepts a sequence to support the empty sequence. If it’s passed a sequence of more than one item, it treats that as if the string values of the items had been concatenated together. This can have slightly surprising consequences as “('a', '3', '0')” will return a string of three spaces whereas “('0', '3', '0')” will return a string of thirty.