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% MISCELLANEOUS RULES
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:- add_rule(
drop_node_into_empty_buffer
if
stack([[SomeHead|RestOfHead]|RestStack])
and buffer([])
and check(not_equal(SomeHead, s))
then
remove(stack(_)) and add(stack(RestStack))
and remove(buffer(_)) and add(buffer([[SomeHead|RestOfHead]]))).

:- add_rule(
successful_parse
if
stack([[s|Contents]])
and buffer([])
then
print('Success! The parse tree is: ')
and print([s|Contents]) and print('\n')
and remove(stack(_)) and add(stack([]))
and remove(buffer(_)) and add(buffer([]))
and end and reset).

:- add_rule(
ask_for_input
if
stack([])
and buffer([])
then
print('What is the next sentence?\n') and read(List)
and remove(stack(_))  and add(stack([[s]]))
and remove(buffer(_)) and add(buffer(List))).

:- add_rule(
failed_parse
if
stack(Contents)
and check(not_equal(Contents, []))
then
print('Parse failed: Current stack: ')
and print(Contents) and print('\n')
and remove(stack(_))  and add(stack([]))
and remove(buffer(_)) and add(buffer([]))
and end and reset).