From: Clinton Ebadi <clinton@unknownlamer.org>
Date: Mon, 24 Nov 2014 02:53:05 +0000 (-0500)
Subject: Painfully trivial automata
X-Git-Url: http://git.hcoop.net/clinton/scratch.git/commitdiff_plain/0bbcd8e73c8a9844644f0c7bb4906104883a38ae?hp=ae6cd47aa12063bed94fe165fe6fedaa92ff69fd

Painfully trivial automata
---

diff --git a/automata.scm b/automata.scm
new file mode 100644
index 0000000..ba77998
--- /dev/null
+++ b/automata.scm
@@ -0,0 +1,27 @@
+(use-modules (srfi srfi-9)
+	     (srfi srfi-1))
+
+(define (next-token stream)
+  (if (pair? stream)
+      (car stream)))
+
+(define (transition machine state)
+  ((cdr (assoc state (cdr machine)))
+   (cons (if (pair? (car machine)) (cdr (car machine)))
+	 (cdr machine))
+   (next-token (car machine))))
+
+(define (run-machine machine initial-state stream)
+  (transition (cons stream machine) initial-state))
+
+(define cadr-machine
+  `((init . ,(lambda (m v) (case v
+		       ((#\c) (transition m 'more))
+		       (else #f))))
+    (more . ,(lambda (m v) (case v
+		       ((#\a #\d) (transition m 'more))
+		       ((#\r) (transition m 'end))
+		       (else #f))))
+    (end . ,(lambda (m v) #t))))
+
+