arrayUtilities: init

Signed-off-by: Connor Baker <ConnorBaker01@gmail.com>

pkgs/build-support/setup-hooks/arrayUtilities/isDeclaredArray/isDeclaredArray.bash

@@ -0,0 +1,14 @@
+# shellcheck shell=bash
+
+# isDeclaredArray
+# Tests if inputArrayRef refers to a declared, indexed array.
+#
+# Arguments:
+# - inputArrayRef: a reference to an indexed array (not mutated)
+#
+# Returns 0 if the indexed array is declared, 1 otherwise.
+isDeclaredArray() {
+  # NOTE: We must dereference the name ref to get the type of the underlying variable.
+  # shellcheck disable=SC2034
+  local -nr inputArrayRef="$1" && [[ ${!inputArrayRef@a} =~ a ]]
+}