gmJoinAVariable(sel,var,nameUse=var,bind=TRUE,db=getOption("gmDB"),selID=attr(sel,"id"))
gmJoinADollarExpr(sel,expr,nameUse,envir,bind=TRUE,db=getOption("gmDB"), gmNameVarID=getGmNameVarID(db))
expr
gmJoinADollarExpression
the new selection expression, where the dollar expression is added.