# version = 1.02 of atchange-computer 2001 Oct 29
# this is an atchange script, see:
# http://www.lecb.ncifcrf.gov/~toms/atchange.html

# Dr. Thomas D. Schneider
# National Cancer Institute
# Laboratory of Experimental and Computational Biology
# Frederick, Maryland  21702-1201
# toms@ncifcrf.gov
# permanent email: toms@alum.mit.edu
# http://www.lecb.ncifcrf.gov/~toms/

# purpose:  Demonstrate that atchange, with shell script if
# can simulate boolean logic circuits.

# There are 5 boolean variables, a, b, c, d and e.
# There are three nodes, node1, node2 and node 3
# node1 is programed as c = a+b (OR function)
# node2 is programed as d = a*b (AND function)
# node3 is programed as e = ~d (NAND function)

# touch reset to set up the booleans and nodes

reset
 echo 0 > a
 echo 0 > b
 echo 0 > c
 echo 0 > d
 echo 0 > e
 echo 0 > node1
 echo 0 > node2
 echo 0 > node3
 echo 'result node' > result
 echo 'listing node' > listing

a
 if (`cat a` == 1) then
   echo a is 1
 else
   echo a is 0
 endif
 touch node1
 touch node2

b
 if (`cat b` == 1) then
   echo b is 1
 else
   echo b is 0
 endif
 touch node1
 touch node2

c
 if (`cat c` == 1) then
   echo c is 1
 else
   echo c is 0
 endif
 touch result

d
 if (`cat d` == 1) then
   echo d is 1
 else
   echo d is 0
 endif
 touch node3
 touch result

e
 if (`cat e` == 1) then
   echo e is 1
 else
   echo e is 0
 endif
 touch result

node1
 if ((`cat a` == 1)||((`cat b`) == 1)) then
    echo '1' > c
 else
    echo '0' > c
 endif

node2
 if ((`cat a` == 1)&&((`cat b`) == 1)) then
    echo '1' > d
 else
    echo '0' > d
 endif

node3
 if (`cat d` == 0) then
    # pause to allow settling
    sleep 2
    echo '1' > e
 else
    # pause to allow settling
    sleep 2
    echo '0' > e
 endif

result
 printf "|---------|\n"           > listing
 printf "| a = %s --|\n" `cat a` >> listing
 printf "| b = %s --|\n" `cat b` >> listing
 printf "| c = %s --| a+b \n" `cat c` >> listing
 printf "| d = %s --| a*b \n" `cat d` >> listing
 printf "| e = %s --| ~d  \n" `cat e` >> listing
 printf "|---------|\n"          >> listing
 cat listing