1 files changed, 26 insertions, 0 deletions
diff --git a/subsystem/karuta/rnt.lfe b/subsystem/karuta/rnt.lfe
new file mode 100644
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+++ b/subsystem/karuta/rnt.lfe
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+;; Tuples of an RNT relation, as Translator.ml writes and reads them: a
+;; tuple is #(Type #m(Name Value ...)), its type, names and strings
+;; binaries, and its integers no wider than an OCaml int.
+(defmodule rnt
+  (export (recv 1) (send 1)))
+
+;; A tuple from the bytes RNT sent.
+(defun recv (bytes) (holdable (binary_to_term bytes '(safe))))
+
+;; The bytes RNT reads a tuple from.
+(defun send (tuple) (term_to_binary (holdable tuple)))
+
+;; The tuple, if RNT can hold it.
+(defun holdable
+  (((= (tuple type attributes) tuple)) (when (is_binary type) (is_map attributes))
+   (if (lists:all (fun attribute? 1) (maps:to_list attributes))
+     tuple
+     (error 'badarg (list tuple))))
+  ((tuple) (error 'badarg (list tuple))))
+
+(defun attribute?
+  (((tuple name value)) (when (is_binary name) (is_binary value)) 'true)
+  (((tuple name value))
+   (when (is_binary name) (is_integer value) (>= value (- (bsl 1 62))) (< value (bsl 1 62)))
+   'true)
+  ((_) 'false))