From Newsgroup: comp.lang.prolog

http://miniprolog.com/INVOICE-DEMO.png



invit ID TOTAL
invitem ID N D P
print N
print D
print P
plus TOTAL TOTAL P
br
false

inv ID
printheader
br
do
invit ID 0
br
tally

printheader ID
invoice ID CLIENT DES TOT
print invoice
print ID
br
client CLIENT NAME ADD
print NAME
print ADD
br

button inv INV
inv INV

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