var$ = UnmidStr(s$, pos, len[, encoding])
len characters from s$ starting at position pos in the
string. The position needs to be specified in characters, not in bytes. Position 0
indicates the start of the string. The truncated string is returned.
The optional encoding parameter can be used to set the character encoding
to use. This defaults to the default string encoding set using SetDefaultEncoding().
See Character encodings for details.
Print(UnmidStr("This is definitely not a funny example", 19, 4))
The task of figuring out what the mysterious call above might do is left
to the reader.