From 72454c395c991fdbbeb00c2beb40a0486ccf9e92 Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Mon, 3 Apr 2023 16:00:37 +0200
Subject: [PATCH] Add lists+vars->tbfs/state.

---
 scribblings/tbn.scrbl | 16 ++++++++++++++++
 tbn.rkt               | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/scribblings/tbn.scrbl b/scribblings/tbn.scrbl
index 80a3fa1..feb6e4a 100644
--- a/scribblings/tbn.scrbl
+++ b/scribblings/tbn.scrbl
@@ -114,3 +114,19 @@ input values.
 (apply-tbf/state (tbf/state (hash 'a 2 'b -2) 1)
                  (hash 'a 1 'b 0 'c 1))
 ]}
+
+@section{Reading TBFs and SBFs}
+
+@defproc[(lists+vars->tbfs/state [vars (Listof Variable)]
+				 [lsts (Listof (Listof Real))])
+				 (Listof TBF/State)]{
+
+Reads a list of @racket[TBF/State] from a list of list of
+@racket[Real]s.
+
+The last element of each list is taken to be the threshold of the
+TBFs, and the rest of the elements are taken to be the weights.
+
+@ex[
+(lists+vars->tbfs/state '(x y) '((1 2 3) (1 1 2)))
+]}
diff --git a/tbn.rkt b/tbn.rkt
index e3ac60d..8602c73 100644
--- a/tbn.rkt
+++ b/tbn.rkt
@@ -24,6 +24,8 @@
 
    (struct-out tbf/state) TBF/State tbf/state-w tbf/state-θ make-tbf/state
    sbf/state? apply-tbf/state
+
+   lists+vars->tbfs/state
    )
 
   (: apply-tbf-to-state (-> TBF (State (U Zero One)) (U Zero One)))
@@ -75,6 +77,22 @@
       (define tbf (make-tbf/state '((a . 2) (b . -2)) 1))
       (check-equal? (apply-tbf/state tbf st1) 1)
       (check-equal? (apply-tbf/state tbf st2) 0)))
+
+  (: lists+vars->tbfs/state (-> (Listof Variable) (Listof (Listof Real))
+                                (Listof TBF/State)))
+  (define (lists+vars->tbfs/state vars lsts)
+    (for/list ([lst (in-list lsts)])
+      (define-values (ws θ) (split-at-right lst 1))
+      (make-tbf/state (for/list ([x (in-list vars)]
+                                 [w (in-list ws)])
+                        (cons x w))
+                      (car θ))))
+
+  (module+ test
+    (test-case "lists+vars->tbfs/state"
+      (check-equal? (lists+vars->tbfs/state '(x y) '((1 2 3) (1 1 2)))
+                    (list (tbf/state '#hash((x . 1) (y . 2)) 3)
+                          (tbf/state '#hash((x . 1) (y . 1)) 2)))))
   )
 
 (module+ test