EFUN: extract

SYNTAX:
string extract( str, from[, to] );
  string str;
  int from;
  int to;

DESCRIPTION:
Extract copies a range of characters from string 'str', starting at
index 'from', up to index 'to'. Like arrays, strings start counting at
index 0. If 'to' is not given, it uses the last character of str by
default. Note that this efun does the same as str[from..to].

RETURN VALUES:
A string that consists of the specified range of characters from
'str' is returned.

SEE ALSO:
strstr
sscanf
explode

EXAMPLE:
string substr;

substr = "Pangalactic Gargleblaster", 5, 10 )
// substr is now "lactic".
substr = "Pangalactic Gargleblaster", 18 )
// substr is now "blaster".
