Welcome to SWI-Prolog (Multi-threaded, Version 5.6.20)
Copyright (c) 1990-2006 University of 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).


Yes

Yes

Command? Echo turned on; prompt turned off

Command: info
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) -- shorten P by Length
echo -- toggle command echo
info -- print this message
done -- exit

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: done

Yes

% halt