remark first normal operation kramer
2
3 add show
remark 5 kramer

macro avg4
  add add
  add add
  4 exch
  div show
orcam

macro welcome
 quote wow_you_got_it
 show
 pop
orcam

pop
remark wow_you_got_it  kramer
welcome

2 2 3 4 5 
avg4
remark 4 kramer
clear

remark variable testing kramer

remark x-4 =1 kramer
5 quote x store
4
x
sub show

remark 3+1 =4 kramer
3 quote y store
y x add show 

remark more complex operation, kramer

0 quote sum store
macro body1
  sum			remark specify the other operand of add kramer

  add 
 quote sum store 

  dup 0 lessthan	remark the top of the stack is T/F kramer
orcam

macro allsum
  remark while we get positive numbers add kramer
  dup			remark dup. the 7 kramer
  0 lessthan 
  quote body1 while
sum show
orcam

clear
-1 1 2 3 4 5 6 7
allsum

remark sum is 28 kramer

clear
remark throw exception with store kramer
4 var store

remark
 output should be 

 5
 wow_you_got_it
 4
 1
 8
 28
kramer