Lower array(data=<non-scalar>, dim=...) via reshape()

R/r2f-constructors.R

@@ -86,7 +86,16 @@ r2f_handlers[["array"]] <- function(args, scope = NULL, ...) {
 
   out <- r2f(args$data, scope, ...)
   if (!passes_as_scalar(out@value)) {
-    stop("array(data=) must be a scalar for now")
+    # R semantics: `array()` flattens its input (dropping dim) then reshapes.
+    # We implement this as `reshape()`; recycling is not supported here.
+    dim_vec <- r2f(args$dim, scope, ...)
+    if (is.null(dim_vec@value) || dim_vec@value@mode != "integer") {
+      stop("array(dim=) must be an integer vector", call. = FALSE)
+    }
+    if (dim_vec@value@rank != 1L) {
+      stop("array(dim=) must be a 1-d integer vector", call. = FALSE)
+    }
+    out <- Fortran(glue("reshape({out}, int({dim_vec}))"), out@value)
   }
 
   out@value <- Variable(

tests/testthat/test-array-reshape.R

@@ -0,0 +1,10 @@
+test_that("array() supports reshaping non-scalar data", {
+  fn <- function(x) {
+    declare(type(x = integer(2L, 3L, 4L)))
+    array(as.double(x), dim = c(2L, 3L, 4L))
+  }
+
+  set.seed(1)
+  x <- array(sample(1:10, 24, replace = TRUE), dim = c(2L, 3L, 4L))
+  expect_quick_identical(fn, list(x))
+})

tests/testthat/test-r2f-r-attr.R

@@ -13,4 +13,3 @@ test_that("r2f() attaches `r` metadata for bind(c) logical symbols", {
   expect_true(inherits(a_var, Variable))
   expect_identical(a_var@r, quote(m))
 })
-