complex language object about constructive HOT 4 CLOSED

Would be miraculously a 3 lines fix with rlang::is_expression() if it returned FALSE when the call hides attributes. See r-lib/rlang#1475

We might have to reprogram is_expression(), the logic doesn't seem extractable easily.
Or we implement another recursive logic but it won't be half as pretty.

from constructive.

There seems to be a logic in rlang to avoid recursion, probably for some stack issues since they stop at 100 anyway. But for our use case this should do it:

is_expression2 <- function(x) {
  if(!is.null(attributes(x))) return(FALSE)
  if (rlang::is_syntactic_literal(x) || rlang::is_symbol(x)) return(TRUE)
  if(!rlang::is_call(x)) return(FALSE)
  all(vapply(x, is_expression2, logical(1)))
}

And we tweak it slightly because we're fine with the top level having attributes :

is_expression2 <- function(x) {
  if (rlang::is_syntactic_literal(x) || rlang::is_symbol(x)) return(TRUE)
  if(!rlang::is_call(x)) return(FALSE)
  all(vapply(x, function(x) is.null(attributes(x)) && is_expression2(x), logical(1)))
}

It works :) :

library(constructive)
x <- quote(a(1)(2))
attr(x[[1]], "foo") <- "bar"
construct(x)
#> as.call(list(
#>   quote(a(1)) |>
#>     structure(foo = "bar"),
#>   2
#> ))

y <- quote(a(1))
y[[1]] <- mean
construct(y)
#> as.call(list(
#>   as.function(alist(x = , ... = , UseMethod("mean")), envir = .BaseNamespaceEnv),
#>   1
#> ))

construct(y, data = list(mean = mean))
#> as.call(list(mean, 1))

from constructive.

Solved in 3b675b9 and improved secret and attribute handling with 593558b

from constructive.

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from constructive.