added example 2.9.1_21

% nacteni:

/* ['2.9.1_21.pl']. */

path(A,Z,Graph,Cesta) :- path1(A,[Z],Graph,Cesta).

path1(A,[A|Cesta1],_,[A|Cesta1]).

path1(A,[Y|Cesta1],Graph,Cesta) :- adjacent(X,Y,Graph),

    \+ member(X,Cesta1),path1(A,[X,Y|Cesta1],Graph,Cesta).

adjacent(X,Y,graph(_,Edges)) :- member(e(X,Y),Edges)

                                    ;member(e(Y,X),Edges).

graph([a,b,c,d],[e(a,b),e(b,d),e(b,c),e(c,d)]).

% demonstracni vypis

start:- 

    write('Cesta v grafu'),nl, nl,

    write('path(a, c, graph, Cesta) : '),

    graph(Nodes,Edges),

    path(a, c, graph(Nodes,Edges), Cesta),

    write(Cesta), nl, nl.

?-start.

#!/usr/bin/env python

# encoding=utf-8 (pep 0263)

from linked_lists import LinkedList, Cons, Nil

def path(a, z, graph):

    for cesta in path1(a, LinkedList(z), graph, 1):

        yield cesta

def path1(a, akumulator_cesty, graph, depth):

    if akumulator_cesty.head == a:

        yield akumulator_cesty

    else:

        y = akumulator_cesty.head

        for x in adjacent_anyX(y, graph):

            if not member(x, akumulator_cesty):

                for cesta in path1(a, Cons(x, akumulator_cesty), graph, depth+1):

                    yield cesta

def adjacent_anyX(y, graph):

    _, edges = graph

    for a, b in member_anyX(edges):

        if y == a:

            yield b

        if y == b:

            yield a

def member(x, xs):

    if xs == Nil:

        return False

    if x == xs.head:

        return True

    return member(x, xs.tail)

def member_anyX(xs):

    if xs == Nil:

        return

    yield xs.head

    for x in member_anyX(xs.tail):

        yield x

_graph = (LinkedList("a", "b", "c", "d"),

          LinkedList(("a", "b"), ("b", "d"), ("b", "c"), ("c", "d")))

# demonstracni vypis

if __name__ == "__main__":

    print('Cesta v grafu\n')

    print('next(path("a", "c", _graph)) : %s' % next(path("a", "c", _graph)))

Cesta v grafu

next(path("a", "c", _graph)) : [a, b, c]

.PHONY: tests output pylint2 pylint3

.PHONY: tests output pylint2 pylint3

IGNORED_PYLINT_TESTS=invalid-name missing-docstring \

IGNORED_PYLINT_TESTS=invalid-name missing-docstring \

	redefined-variable-type too-few-public-methods

	redefined-variable-type too-few-public-methods duplicate-code

IGNORED_PYLINT2_TESTS=superfluous-parens duplicate-code

IGNORED_PYLINT2_TESTS=superfluous-parens

IGNORED_PYLINT3_TESTS=duplicate-code

IGNORED_PYLINT3_TESTS=

tests:

tests:

	# all tests

	# all tests