From bb247d9eb88b3e167a7ca63ba80609d5dda9af10 Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Sun, 1 Mar 2020 19:05:28 +0100
Subject: [PATCH] rs: Start.

---
 rs-tests.rkt | 12 ++++++++++++
 rs.rkt       | 31 +++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 rs-tests.rkt
 create mode 100644 rs.rkt

diff --git a/rs-tests.rkt b/rs-tests.rkt
new file mode 100644
index 0000000..9601a08
--- /dev/null
+++ b/rs-tests.rkt
@@ -0,0 +1,12 @@
+#lang typed/racket
+
+;;; Tests for dds/rs.
+
+(require typed/rackunit "rs.rkt")
+
+(test-case "Basic definitions"
+  (let ([r (reaction (set 'a) (set 'b) (set 'c))]
+        [s1 (set 'a 'c)]
+        [s2 (set 'a 'b)])
+    (check-true (enabled? r s1))
+    (check-false (enabled? r s2))))
diff --git a/rs.rkt b/rs.rkt
new file mode 100644
index 0000000..69e3dc7
--- /dev/null
+++ b/rs.rkt
@@ -0,0 +1,31 @@
+#lang typed/racket
+
+;;; dds/rs
+
+;;; Definitions for working with reaction systems.
+
+(provide
+ ;; Structures
+ reaction
+ ;; Functions
+ enabled?)
+
+;;; =================
+;;; Basic definitions
+;;; =================
+
+;;; A species is a symbol.
+(define-type Species Symbol)
+
+;;; A reaction is a triple of sets, giving the reactants, the
+;;; inhibitors, and the products, respectively.
+(struct reaction ([reactants : (Setof Symbol)]
+                  [inhibitors : (Setof Symbol)]
+                  [products : (Setof Symbol)]))
+
+;;; A reaction is enabled on a set if all of its reactants are in the
+;;; set and none of its inhibitors are.
+(: enabled? (-> reaction (Setof Symbol) Boolean))
+(define/match (enabled? r s)
+  [((reaction r i p) s)
+   (and (subset? r s) (set-empty? (set-intersect i s)))])