Hi baucez. Well, gppg parsers can work with any scanner, interactive or not. However building interactive *scanners* is sometimes tricky.
If you have an incremental scanner, one that returns symbols as they are typed in, then the parser may behave a little unexpectedly.
gppg parsers can sometimes make a parsing decision without needing a lookahead symbol, but in other circumstances will not make a move until it has seen the next symbol. This sometimes appears a little odd.
Writing interactive scanners is likewise tricky, because a scanner needs one character of lookahead before it can declare that it has recognized *any* regular expression. For example if you have a C# scanner that has just read f,o,r, then it cannot return
the token "keyword-for" without checking if the following characters are "each". Usually it can work if input is read line-by-line and no regular expression contains a line-separator.
Other than this I can't give any general guidelines.