From 9ce3040240a2acf2c9e5b8b135117eddcea59ccf Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Tue, 3 Mar 2020 00:51:53 +0100
Subject: [PATCH] rs: Add build-interactive-process.

---
 rs-tests.rkt | 10 +++++++++-
 rs.rkt       | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/rs-tests.rkt b/rs-tests.rkt
index b64560b..d25b355 100644
--- a/rs-tests.rkt
+++ b/rs-tests.rkt
@@ -73,4 +73,12 @@
                                (state (set 'y 'z) (list (set 'y) (set 'z) (set) (set 'z))))
                   (set (set 'a 'b)))
 
-    (check-equal? sgr ip)))
+    (check-equal? sgr ip)
+
+    (check-equal? (build-interactive-process rs (list (set 'x) (set 'y) (set 'z) (set) (set 'z)))
+                  (list
+                   (list (set 'x) (set))
+                   (list (set 'y) (set 'y 'z))
+                   (list (set 'z) (set))
+                   (list (set) (set))
+                   (list (set 'z) (set))))))
diff --git a/rs.rkt b/rs.rkt
index 142fe60..7b6a855 100644
--- a/rs.rkt
+++ b/rs.rkt
@@ -27,6 +27,7 @@
                [dds-build-state-graph-annotated (-> dynamics? (set/c state? #:kind 'dont-care) graph?)]
                [dds-build-n-step-state-graph-annotated (-> dynamics? (set/c state? #:kind 'dont-care) number? graph?)]
                [build-interactive-process-graph (-> reaction-system/c (listof (set/c species?)) graph?)]
+               [build-interactive-process (-> reaction-system/c (listof (set/c species?)) (listof (list/c (set/c species?) (set/c species?))))]
                [pretty-print-state-graph (-> graph? graph?)])
  ;; Predicates
  (contract-out [species? (-> any/c boolean?)])
@@ -173,6 +174,24 @@
   (dds-build-state-graph-annotated (dynamics rs)
                                    (set (state (set) contexts))))
 
+;;; Builds the interactive process driven by the given context
+;;; sequence.  The output is a list of pairs of lists in which the
+;;; first element is the current context and the second element is the
+;;; result of the application of reactions to the previous state.  The
+;;; interactive process stops when there are no more contexts left.
+(define (build-interactive-process rs contexts)
+  (let ([dyn (dynamics rs)])
+    (for/fold ([proc '()]
+               [st (state (set) contexts)]
+               #:result (reverse proc))
+              ([c contexts])
+      (values
+       (cons (match st
+               [(state res ctx)
+                (list (if (empty? ctx) (set) (car ctx)) res)])
+             proc)
+       (set-first (dds-step-one dyn st))))))
+
 ;;; Pretty-prints the context sequence and the current result of a
 ;;; state of the reaction system.  Note that we need to keep the full
 ;;; context sequence in the name of each state to avoid confusion