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'.

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!

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()

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()

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