Add quotation automatically for string field expression

[igarashitm]

Please describe the feature that you want to propose

Make sure they are not typing for the node path... how and when?
When DataMapper should determine it's a string literal and put the quotation? What if user is just in the middle of writing a field path or function? Is there a deterministic way to distinguish?

Update

This sounds failr - only when user start to type in an empty expression, and if it's a string field, start with 2 double quotes and put the cursor in between.