NAME

       function::substr - Returns a substring

SYNOPSIS

           substr:string(str:string,start:long,length:long)

ARGUMENTS

       str
           the string to take a substring from

       start
           starting position of the extracted string (first character is 0)

       length
           length of string to return

DESCRIPTION

       Returns the substring of the given string at the given start position with the given
       length (or smaller if the length of the original string is less than start + length, or
       length is bigger than MAXSTRINGLEN).