From c6aab50304f501b407beeecc765138a7b0998222 Mon Sep 17 00:00:00 2001
From: grammarware <spider.vz@gmail.com>
Date: Wed, 20 Jun 2012 14:39:19 +0200
Subject: [PATCH] duplicate

---
 examples/dup/README.txt | 13 ++++++++++++
 examples/dup/copy2.ctur | 36 ++++++++++++++++++++++++++++++++
 examples/dup/copy2.t_l2 | 46 +++++++++++++++++++++++++++++++++++++++++
 examples/dup/dup.ctur   | 20 ++++++++++++++++++
 examples/dup/dup.t_l2   | 25 ++++++++++++++++++++++
 5 files changed, 140 insertions(+)
 create mode 100644 examples/dup/README.txt
 create mode 100644 examples/dup/copy2.ctur
 create mode 100644 examples/dup/copy2.t_l2
 create mode 100644 examples/dup/dup.ctur
 create mode 100644 examples/dup/dup.t_l2

diff --git a/examples/dup/README.txt b/examples/dup/README.txt
new file mode 100644
index 0000000..cd58df5
--- /dev/null
+++ b/examples/dup/README.txt
@@ -0,0 +1,13 @@
+There are two simple Turing Machine programs that duplicate a unary number.
+
+copy2 is the naïve implementation of concatenating two copy (cf.) programs.
+It requires the first bit set to 0 in order to find it back.
+(In the Rascal emulator you cannot move backwards farther than your starting position)
+
+e.g.: 0110… ⇒ 011011110…
+
+dup is a slightly less naïve but stupid implementation, which does what copy (cf.) does,
+but adds two bits on each iteration.
+It shows how Turing Machine programming does not have to be rocket science.
+
+-- Vadim Zaytsev, http://grammarware.net
diff --git a/examples/dup/copy2.ctur b/examples/dup/copy2.ctur
new file mode 100644
index 0000000..f4eaa0b
--- /dev/null
+++ b/examples/dup/copy2.ctur
@@ -0,0 +1,36 @@
+MF
+J036
+J034
+W0
+MF
+J15
+MF
+J17
+W1
+MB
+J110
+MB
+J112
+W1
+MF
+J13
+MB
+J117
+MF
+J034
+W0
+MF
+J122
+MF
+J124
+W1
+MB
+J127
+MB
+J129
+W1
+MF
+J120
+MF
+J134
+
diff --git a/examples/dup/copy2.t_l2 b/examples/dup/copy2.t_l2
new file mode 100644
index 0000000..3d9deb3
--- /dev/null
+++ b/examples/dup/copy2.t_l2
@@ -0,0 +1,46 @@
+MF
+J0 stop
+L loop
+  J0 exit
+  W0
+  REP 2 {
+    L skip
+      MF
+      J1 skip
+  }
+  W1
+  REP 2 {
+    L back
+      MB
+      J1 back
+  }
+  W1
+  MF
+  J1 loop
+L back2
+  MB
+  J1 back2
+  MF
+L loop2
+  J0 exit
+  W0
+  REP 2 {
+    L skip2
+      MF
+      J1 skip2
+  }
+  W1
+  REP 2 {
+    L back3
+      MB
+      J1 back3
+  }
+  W1
+  MF
+  J1 loop2
+L exit
+L end
+  MF
+  J1 end
+L stop
+
diff --git a/examples/dup/dup.ctur b/examples/dup/dup.ctur
new file mode 100644
index 0000000..85556ff
--- /dev/null
+++ b/examples/dup/dup.ctur
@@ -0,0 +1,20 @@
+J020
+J018
+W0
+MF
+J14
+MF
+J16
+W1
+MF
+W1
+MB
+J111
+MB
+J113
+W1
+MF
+J12
+MF
+J118
+
diff --git a/examples/dup/dup.t_l2 b/examples/dup/dup.t_l2
new file mode 100644
index 0000000..0f1f532
--- /dev/null
+++ b/examples/dup/dup.t_l2
@@ -0,0 +1,25 @@
+J0 stop
+L loop
+  J0 end
+  W0
+  REP 2 {
+    L skip
+      MF
+      J1 skip
+  }
+  W1
+  MF
+  W1
+  REP 2 {
+    L back
+      MB
+      J1 back
+  }
+  W1
+  MF
+  J1 loop
+L end
+  MF
+  J1 end
+L stop
+