Issue passing in a parameter to a ggplot command not working

[merrittr]

I have a parameter

  selectInput(inputId = "y", 
              label = "Y-axis:",
              choices = c("Water Level" = "waterlevel", 
                          "Discharge Debit" = "dischargedebit"), 
              selected = "waterlevel")

Which is supposed to supply a parameter too

output$lineplot <- renderPlot({
ggplot(aes(x=datetime, y=input$y), data = subds) + geom_line()
})

and here is what i get .....if i hardcode in y=waterlevel it works ....any ideas

here is the ful code
http://www.merrittnet.org/r/hydroShiny.txt

[andresrcs]

Use tidy evaluation y = !!as.name(input$y)

[merrittr]

@andresrcs

!!as.name(input$y)

that did it !!!!!!

Thanks andre