examples: a rule for 5 of 7 tests passing

[Michael Cariaso]

while the pyke documentation is extensive, it seems a bit light on examples. Can anyone show me a PyKE analog for this topic from the CLIPS forum?
http://groups.google.com/group/CLIPSESG/browse_thread/thread/211d246a12fae3cb

Short version: I need a rule that lets me ask if at least X of these Y tests pass. The tests are all simple 'is this fact true'.

[Bruce Frederiksen]

Here's a way to do it with backward chaining:

---------- cut here ----------------
# rules.krb
#
# This creates a rule base called 'rules' (filename, minus the .krb suffix).

have_at_least:
    # This rule just provides a simplier interface to have_at_least_excluding.
    use have_at_least($n)
    when
        have_at_least_excluding($n, ())

have_at_lease_excluding_0:
    # We always have at least 0 students!
    use have_at_least_excluding(0, $_)
    # Without a 'when' clause, this rule succeeds if the 'use' pattern can
    # be matched.

have_at_least_excluding_n:
    # To prove whether we have at least $n students, excluding $exclude_list,
    use have_at_least_excluding($n, $exclude_list)
    when
        # Find a student
        fact.student($name)
        # That is not already in the $exclude_list
        check $name not in $exclude_list
        # And prove that there are $n - 1 students, excluding this one and
        # the ones in $exclude_list.  The pattern "($name, *$exclude_list)"
        # is a tuple whose first element is $name, with the rest of the
        # elements being the $exclude_list tuple.
        $n_1 = $n - 1
        have_at_least_excluding($n_1, ($name, *$exclude_list))

--------- end cut ---------------

You can run this with:

---------- cut here -------------
# run.py

import pyke

# Add our 'student' facts.  We'll put these facts in the 'fact' fact base.
pyke.add_universal_fact('fact', 'student', ('Alice',))
pyke.add_universal_fact('fact', 'student', ('Bob',))
pyke.add_universal_fact('fact', 'student', ('Charles',))
pyke.add_universal_fact('fact', 'student', ('Dave',))

# Load the .krb files.  Defaults to looking recursively in the current
# directory.  Will place the compiled .py files in a (new) ./compiled_krb
# directory.
pyke.load()

# Activate the 'rules' rule base.
pyke.activate('rules')

def have_at_least(n):
    '''
        The python function to call the pyke rule.

        >>> have_at_least(3)
        True
        >>> have_at_least(4)
        True
        >>> have_at_least(5)
        False
    '''
    try:
        pyke.prove_1('rules', 'have_at_least', (n,), 0)
        return True
    except pyke.CanNotProve:
        return False

def test():
    import doctest
    import sys
    sys.exit(doctest.testmod()[0])

if __name__ == "__main__":
    test()

------------ end cut --------------------

Run:

   $ python run.py

to run the doctests.  Note that it creates the ./compiled_krb/rules_bc.py the first time it is run, but not the second (unless you change the rules.krb file).

Hope this helps!

[Bruce Frederiksen]

Oops!  The sourceforge forum destroyed the indenting.  Let's try it again.  You'll have to delete the first character on each line here...

-------------- cut here ----------------
|# rules.krb
|#
|# This creates a rule base called 'rules' (filename, minus the .krb suffix).
|
|have_at_least:
|    # This rule just provides a simplier interface to have_at_least_excluding.
|    use have_at_least($n)
|    when
|        have_at_least_excluding($n, ())
|
|have_at_lease_excluding_0:
|    # We always have at least 0 students!
|    use have_at_least_excluding(0, $_)
|    # Without a 'when' clause, this rule succeeds if the 'use' pattern can
|    # be matched.
|
|have_at_least_excluding_n:
|    # To prove whether we have at least $n students, excluding $exclude_list,
|    use have_at_least_excluding($n, $exclude_list)
|    when
|        # Find a student
|        fact.student($name)
|        # That is not already in the $exclude_list
|        check $name not in $exclude_list
|        # And prove that there are $n - 1 students, excluding this one and
|        # the ones in $exclude_list.  The pattern "($name, *$exclude_list)"
|        # is a tuple whose first element is $name, with the rest of the
|        # elements being the $exclude_list tuple.
|        $n_1 = $n - 1
|        have_at_least_excluding($n_1, ($name, *$exclude_list))

--------------- second cut -------------------
|# run.py
|
|import pyke
|
|# Add our 'student' facts.  We'll put these facts in the 'fact' fact base.
|pyke.add_universal_fact('fact', 'student', ('Alice',))
|pyke.add_universal_fact('fact', 'student', ('Bob',))
|pyke.add_universal_fact('fact', 'student', ('Charles',))
|pyke.add_universal_fact('fact', 'student', ('Dave',))
|
|# Load the .krb files.  Defaults to looking recursively in the current
|# directory.  Will place the compiled .py files in a (new) ./compiled_krb
|# directory.
|pyke.load()
|
|# Activate the 'rules' rule base.
|pyke.activate('rules')
|
|def have_at_least(n):
|    '''
|        The python function to call the pyke rule.
|
|        >>> have_at_least(3)
|        True
|        >>> have_at_least(4)
|        True
|        >>> have_at_least(5)
|        False
|    '''
|    try:
|        pyke.prove_1('rules', 'have_at_least', (n,), 0)
|        return True
|    except pyke.CanNotProve:
|        return False
|
|def test():
|    import doctest
|    import sys
|    sys.exit(doctest.testmod()[0])
|
|if __name__ == "__main__":
|    test()

[Bruce Frederiksen]

Nope that didn't work either...

Third time's a charm (I hope)!  You'll have to pipe this through "sed 's/^/ /g'"...

-------- cut here --------------
# rules.krb
#
# This creates a rule base called 'rules' (filename, minus the .krb suffix).

have_at_least:
^^^^# This rule just provides a simplier interface to have_at_least_excluding.
^^^^use have_at_least($n)
^^^^when
^^^^^^^^have_at_least_excluding($n, ())

have_at_lease_excluding_0:
^^^^# We always have at least 0 students!
^^^^use have_at_least_excluding(0, $_)
^^^^# Without a 'when' clause, this rule succeeds if the 'use' pattern can
^^^^# be matched.

have_at_least_excluding_n:
^^^^# To prove whether we have at least $n students, excluding $exclude_list,
^^^^use have_at_least_excluding($n, $exclude_list)
^^^^when
^^^^^^^^# Find a student
^^^^^^^^fact.student($name)
^^^^^^^^# That is not already in the $exclude_list
^^^^^^^^check $name not in $exclude_list
^^^^^^^^# And prove that there are $n - 1 students, excluding this one and
^^^^^^^^# the ones in $exclude_list.  The pattern "($name, *$exclude_list)"
^^^^^^^^# is a tuple whose first element is $name, with the rest of the
^^^^^^^^# elements being the $exclude_list tuple.
^^^^^^^^$n_1 = $n - 1
^^^^^^^^have_at_least_excluding($n_1, ($name, *$exclude_list))
------------------ second cut ---------------------
# run.py

import pyke

# Add our 'student' facts.  We'll put these facts in the 'fact' fact base.
pyke.add_universal_fact('fact', 'student', ('Alice',))
pyke.add_universal_fact('fact', 'student', ('Bob',))
pyke.add_universal_fact('fact', 'student', ('Charles',))
pyke.add_universal_fact('fact', 'student', ('Dave',))

# Load the .krb files.  Defaults to looking recursively in the current
# directory.  Will place the compiled .py files in a (new) ./compiled_krb
# directory.
pyke.load()

# Activate the 'rules' rule base.
pyke.activate('rules')

def have_at_least(n):
^^^^'''
^^^^^^^^The python function to call the pyke rule.

^^^^^^^^>>> have_at_least(3)
^^^^^^^^True
^^^^^^^^>>> have_at_least(4)
^^^^^^^^True
^^^^^^^^>>> have_at_least(5)
^^^^^^^^False
^^^^'''
^^^^try:
^^^^^^^^pyke.prove_1('rules', 'have_at_least', (n,), 0)
^^^^^^^^return True
^^^^except pyke.CanNotProve:
^^^^^^^^return False

def test():
^^^^import doctest
^^^^import sys
^^^^sys.exit(doctest.testmod()[0])

if __name__ == "__main__":
^^^^test()

[Michael Cariaso]

Thanks Bruce,

The example needed a few tweaks to work for me. I've posted the updated version at
http://www.runblast.com/wiki/index.php?title=Pyke_example

mike

http://www.cariaso.com