Feature Request: SQL parameters

Some years ago I worked with another DB tool, for another DB that
offered support for SQL parameters in a way that was extremely handy.
I've missed this feature in pgAdmin ever since. By SQL parameters, I
mean the replaceable bits one puts as ? in a prepared statement.

When testing / debugging sql from application code, it is a major
annoyance to have to constantly find and replace these ?'s. I forget
exactly how the feature in the other tool worked...it may have actually
detected the ?'s and prompted you for values the moment you tried to
execute it. But the important thing was that it allowed you to leave the
?'s in the query, and gave you a place to fill in the parameter values
to be used when you execute it. This may not sound like much on the
surface, but makes an enormous difference. It:

* avoids having to hunt down the ? in a large complex query
* keeps your query looking more as it appears in your source code (and
you can more easily paste it back in after you've modified it in pgadmin)
* keeps you from losing track of where the ?s were before you replaced them
* is handier for testing out different values for the parameters.