do.call tinyplot_add

[FlorianSchwendinger]

Hey tinyplot maintainers, first, thank you for this excellent package, which makes plotting a delight.

I recognized since version 0.5.0 do.call does not work any more in combination with tinyplot_add (in version tinyplot_0.4.2 it did work as expected).

Below is a minimal example to reproduce the error. Note you have to start a fresh R session where tinyplot was not used jet.

library("tinyplot")

df <- data.frame(x = 1:10, y = (1:10)^2)

# Raises no previous tinyplot call found error.
do.call(tinyplot, list(y ~ x, data = df, type = "p"))
tinyplot_add(type = "l", data = df)
#R> Error in tinyplot_add(type = "l", data = df) :
#R>   No previous tinyplot call found.

# Workes fine.
tinyplot(y ~ x, data = df, type = "p")
tinyplot_add(type = "l", data = df)

The issue seams to be that the following regex does not match when using do.call

    calls = sys.calls()
    tinyplot_calls = "(^tinyplot$)|(^tinyplot::tinyplot$)|(^plt$)|(^tinyplot::plt)|(^tinyplot:::)"
    idx = grep(tinyplot_calls, sapply(calls, function(k) k[[1]]))

since sys.calls() gives in this case

[[1]]
do.call(tinyplot, list(y ~ x, data = df, type = "p"))

[[2]]
(function (x, ...) 
{
    UseMethod("tinyplot")
})(y ~ x, data = list(x = 1:10, y = c(1, 4, 9, 16, 25, 36, 49, 
64, 81, 100)), type = "p")

[[3]]
tinyplot.formula(y ~ x, data = list(x = 1:10, y = c(1, 4, 9, 
16, 25, 36, 49, 64, 81, 100)), type = "p")

[[4]]
tinyplot.default(x = x, y = y, by = by, facet = facet, facet.args = facet.args, 
    data = data, type = type, xmin = mf[["(xmin)"]], xmax = mf[["(xmax)"]], 
    ymin = mf[["(ymin)"]], ymax = mf[["(ymax)"]], xlim = xlim, 
    ylim = ylim, main = main, sub = sub, xlab = xlab, ylab = ylab, 
    ann = ann, axes = axes, frame.plot = frame.plot, asp = asp, 
    grid = grid, legend_args = legend_args, pch = pch, col = col, 
    lty = lty, lwd = lwd, restore.par = restore.par, ...)

You might could use something like that instead of the grep, since comparing objects should
be more reliable.

is_tinyplot_method <- function(x) {
  fun <- try(eval(x[[1]]), silent = TRUE)
  identical(tinyplot::tinyplot, fun)
}
idx <- which(as.logical(lapply(calls, is_tinyplot_method)))

Hope this helps.

[grantmcdermott]

Thanks very much for the detailed report @FlorianSchwendinger.

@zeileis would you be able to look into this when you get a sec?

[zeileis]

Florian, sorry for the inconvenience and thanks for digging into this. I didn't think about do.call(), good catch. I'll try to look at this later today.

[zeileis]

Thanks again for the report @FlorianSchwendinger, very much appreciated. Apologies for the delay...I was hit by the new semester (with 850 instead of the expected 700 first-year students in my course).

Finally, I had a closer look, slightly tweaked your suggested code, added a NEWS item and test case, and opened a PR.

Grant @grantmcdermott does this look ok to you?