[ESS] distinguish busy from non-busy waiting

[Vitalie Spinu]

>> On Mon, Nov 30 2015 12:01, Lionel Henry wrote:

>> On 30 nov. 2015, at 11:51, Vitalie Spinu <spinuvit using gmail.com> wrote:
>> 
>> Maybe this is a feature request for R folks. If R is waiting for promt, it
>> should output a different prompt symbol from when the engine is actually
>> running.

> I think we could probably just check if the input is a balanced
> expression by running (ess-forward-sexp) throughout the input. If it
> returns nil at one point, the expression is not balanced.

You mean to accumulate user input in a cache buffer and detect there if it's
balanced or not? It might work, but I am not sure if this complication would be
worth the bang.

An alternative that other emacs systems adopt is to prohibit accumulation and
send only syntactically valid expressions.

  Vitalie