Init an article about wrapping glue #338
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vignettes/wrappers.Rmd
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| Spoiler alert: here's the correct way to write such a wrapper: | ||
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| ```{r} | ||
| myglue <- function(..., .envir = parent.frame()) { |
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Can we find a more compelling example based on one of our glue wrapper? I think it's pretty unusual to want to change the delimiters.
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Based on my own experience and, now, from GitHub searches, I don't have any better ideas. People really do write wrappers to fiddle with the delimiters and I think other examples are probably too exotic.
But if there's a concrete alternative, I'm happy to have a go.
vignettes/wrappers.Rmd
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| Let's make new artificial versions of our functions that make it easy to tell where the inner `glue()` call is getting its values. | ||
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| ```{r} | ||
| myglue1 <- function(...) { |
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I think this would be easier to explain first, before you introduce all the complexities of a real example. Maybe something like this:
x <- 0
myglue1 <- function(...) {
x <- 1
myglue2(...)
}
myglue2 <- function(...) {
x <- 2
glue::glue(...)
}
myglue2("{x}")There was a problem hiding this comment.
Or maybe:
x <- 0
y <- 0
z <- 0
myglue1 <- function(...) {
x <- 1
y <- 1
myglue2(...)
}
myglue2 <- function(...) {
x <- 2
glue::glue(...)
}
myglue2("{x} {y} {z}")
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OK I tried to respond to the feedback. I'm afraid it might now be in some weird intermediate state between how I would approach writing this and how you would. But see what you think. |
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| myglue0(fn_def, NAME = "one_plus_one", BODY = "1 + 1") | ||
| named_list_to_items <- function(x) { | ||
| my_glue("\\item{<@names(x)@>}{<@x@>}") |
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Now that I think of it, is there a reason to not do just < and >?
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That would work in this exact example, but I don't want to model that in a vignette. I know some folks will copy exactly what they see here and I think < and > are too likely to collide with text in the template that should not get evaluated. Generally speaking.
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What about (( or [[? I'm just thinking that <@ looks hard to type.
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Well all of those come up a lot in real R code (like, the code you might want to evaluate) so again I shied away from them. It really sucks that you can't use <<. You can't even triple them <<< because that also matches knitr's regex (unintentionally, I think).
| Here's an abbreviated excerpt of the roxygen comment that generates the documentation for the starwars dataset in dplyr: | ||
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| ```r | ||
| #' \describe{ |
| @@ -25,7 +25,7 @@ Therefore, you'd prefer to use `<<` and `>>` as the opening and closing delimite | |||
| Spoiler alert: here's the correct way to write such a wrapper: | |||
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| ```{r} | |||
| myglue <- function(..., .envir = parent.frame()) { | |||
| my_glue <- function(..., .envir = parent.frame()) { | |||
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Might be worth a footnote pointing out that this is the same pattern you use in abort()/cli_abort() wrappers? And in defer()?
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I was thinking the same! I added a sentence in the intro. I think it's worthy to point this out.
Closes #281