Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 6.6.5)
Copyright (c) 1990-2013 University of Amsterdam, VU Amsterdam
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

true.

true.

Echo turned on; prompt turned off

Command: help
pipes -- show the current set of pipes
weld(P1,P2) -- weld P2 onto P1
cut(P1,P2Len,P2) -- cut P2Len off P1, forming P2
trim(P,Length) -- trim Length off of P
echo -- toggle command echo
help -- print this message
q -- quit

Command: pipes
a, length: 10, diameter: 1
b, length: 5, diameter: 1
c, length: 20, diameter: 2

Command: weld(a,b)
b welded onto a

Command: pipes
a, length: 15, diameter: 1
c, length: 20, diameter: 2

Command: trim(a,12)
12 trimmed from a

Command: pipes
a, length: 3, diameter: 1
c, length: 20, diameter: 2

Command: cut(c,10,d)
10 cut from c to form d

Command: pipes
a, length: 3, diameter: 1
c, length: 10, diameter: 2
d, length: 10, diameter: 2

Command: cut(c,6,c1)
6 cut from c to form c1

Command: weld(d,c1)
c1 welded onto d

Command: pipes
a, length: 3, diameter: 1
c, length: 4, diameter: 2
d, length: 16, diameter: 2

Command: q
true.


% halt