Colour invalid lines in red - don't evaluate until the line is 'complete' i.e. the cursor is no longer on the line - "messages" box or floating window to show these issues - line numbers are useful here, see #53 alterntively status bar could say "Error line 4: Unknown participant 'Srever'"
Colour invalid lines in red
alterntively status bar could say "Error line 4: Unknown participant 'Srever'"