library(RPostgreSQL)
get_connection <- function(connection = current_connection)
{
  drv <- dbDriver("PostgreSQL")
  con <- dbConnect(drv, dbname = connection,
                   host = "localhost", port = 5432,
                   user = "postgres", password = "dbpass")
  con
}
c <- get_connection("€18")

Error in postgresqlNewConnection(drv, ...) :
  RS-DBI driver: (could not connect postgres@localhost on dbname "€18"
)