Errors are displayed in red and fall into two classes.
Parsing of the cell content is checked by the kernel before sending to the server for evaluation. The usual q parsing rules apply. Note that for foreign languages (lines preceded by
p) for example) parsing is not checked.
Runtime errors are reported from the server. One important thing to note is that as with q scripts, lines up to where the error occurred will have been executed.
a:1 b:a+` a:2
will result in
a having a value of 1.