Running the example of R/funs.R produces and error due to wrong (typo) trigger elements:

Listening on http://127.0.0.1:7407
Warning: Error in : [Gargoyle] Flag airquality hasn't been initiated: can't listen to it.
  43: stop
  42: stop_if
  41: on
  40: server [#29]
   3: runApp
   2: print.shiny.appobj
   1: <Anonymous>
Error : [Gargoyle] Flag airquality hasn't been initiated: can't listen to it.

Can be fixed by changing line 30 to init("airquality", "iris", "renderiris"), see #9

Hi @ColinFay ,

Thank you so much for {gargoyle}. A colleague of mine and I have been implementing it a lot.

Once in a while , I get this error when I launch the app for the first time. Do you know why? We've initiated, triggered and watched (through gargoyle::on()) our events correctly but still.

Making shiny dashboards, using golem, it was working fine, but then, in a new shiny dashboard, also using golem, now this occurs:

--- in app_server.R:
...
gargoyle::init("ggl_test")
...
--- in mod_1_server:
...
gargoyle::trigger("ggl_test")
...
--- in another mod:
...
gargoyle::on("ggl_test", {
	print("ok1") # this runs only when calling mod_1_server (expected behavior)
})
shiny::observeEvent(gargoyle::watch("ggl_test"), {
	print("ok2") # this runs when calling mod_1_server but also when the app starts (before calling mod_1_server) - not supposed to happen 
})

When working with the tests/testthat/test-funs.R file I realized that the following code part does not work:

library(shiny)
library(gargoyle)

shiny::reactiveConsole(TRUE)
s <- shiny::MockShinySession$new()

init("pif", session = s)
#> [[1]]
#> reactiveVal: [1] "0"
test_for_on_function <- on(
  "pif",
  {
    cat("TEST fails")
  },
  session = s
)
test_for_on_function$.func()
#> Error in session$userData[[name]](): attempt to apply non-function
shiny::reactiveConsole(FALSE)

A more specific error message is goes on:

This is probably because inside the on() function:

on <- function(
  name,
  expr,
  session = getDefaultReactiveDomain()
  ){
  ...
  observeEvent(
      substitute(gargoyle::watch(name)),
  ...
}

the gargoyle::watch(name) does not update the session i.e. it should probably be gargoyle::watch(name, session = session).

May be fixed by #18

Hey Colin,

Thanks for this package which is really cool to deal with reactivity in shiny apps, in particular when we use module like with the golem framework.

I am developping a golem app and I started by using your function that I borrowed from your hexmake app and it works well. Now that gargoyle is on CRAN I am changing the code by importing the needed functions. I never use watch() but only trigger() and on() (and obviously init()). After removing the internal function and switch to @importFrom gargoyle trigger on init it didn't work anymore. I figured the problem out by adding watch() in the @importFrom gargoyle section even if I never use directly the watch() function

I am under the impression that I shouldn't have to add watch() because it is included in on() function, but maybe I am wrong. What do you think?

Thanks

Hi @ColinFay

please consider an update of gargoyle with the current PR's or at least merging #18 if otherwise it takes too much time.

I need this #18 fix in an app I am working now, otherwise I'd have to use gargoyle with the app on my fix branch or consider some esoteric workarounds for the control flow (it uses a different session in the whole shiny::module(), it's complicated and it would cost quite some time to unwrap the trigger/watch mechanisms already implemented).

Also, the current PR's are rather small and straightforward, let me know if I can help ... the update would be very much welcome and I'd be super happy if you could find the time.

library(shiny)
library(gargoyle)
options("gargoyle.talkative" = TRUE)
ui <- function(request){
  tagList(
    h4('Go'),
    actionButton("y", "y"),
    actionButton("z", "z"),
    h4('Output of z$v'),
    tableOutput("evt")
  )
}

server <- function(input, output, session){
  
  # Initiating the flags
  init( "airquality", "iris", "renderiris", "a2")
  
  # Creating a new env to store values, instead of
  # a reactive structure
  z <- new.env()
  
  observeEvent( input$y , {
    z$v <- mtcars
    # Triggering the flag
    trigger("airquality")
  })
  
  observeEvent( input$y , {
    #z$v <- mtcars
    # Triggering the flag
    trigger("a2")
  })
  
  on("airquality", {
    # Triggering the flag
    z$v <- airquality
    trigger("iris")
  })
  
  on("iris", {
    # Triggering the flag
    z$v <- iris
    trigger("renderiris")
  })
  
  ## need to use both 'iris' & 'a2'
  on({"iris", "a2"},{
    print("observed!")
  })
  
  output$evt <- renderTable({
    # This part will only render when the renderiris
    # flag is triggered
    watch("renderiris")
    head(z$v) 
  })
  
}

shinyApp(ui, server)

Note: It doesn't work!

Let's port of https://github.com/ColinFay/odds here.

With memory storage (cachem), disk storage (qs), and remote (memoise + bank)

Which is a good thing! :)