The VisualDFA constructor checks the dfa parameter using

This checks if dfa is truthy. Since the DFA class defines a __len__ method (and no __bool__), is is truthy iff len(dfa) != 0. Unfortunately, the length checks the dfa's cardinality, i.e., the size if the input language. For infinite-language DFAs, an exception is then raised. As a result, infinite DFAs cannot be visualized.

This could be fixed by testing if dfa is None. VisualNFA is not affected since NFA does not define a __len__ method at the moment, but would fail if a similar method would be added to NFA.

MRE

Using most recent versions:

• automata-lib 7.0.1
• visual_automata 1.1.1

from automata.fa.dfa import DFA
from visual_automata.fa.dfa import VisualDFA

dfa = DFA(states={"q0"}, input_symbols={"i0"}, transitions={"q0": {"i0": "q0"}}, initial_state="q0",
          final_states={"q0"})
VisualDFA(dfa).show_diagram(view=True)

Expected Behavior

The automaton is shown.

Actual Behavior

Traceback (most recent call last):
  File "/path/to/scratch_1.py", line 6, in <module>
    VisualDFA(dfa).show_diagram(view=True)
  File "/path/to/site-packages/visual_automata/fa/dfa.py", line 34, in __init__
    if dfa:
  File "/path/to/site-packages/automata/fa/dfa.py", line 160, in __len__
    return self.cardinality()
  File "/path/to/site-packages/automata/fa/dfa.py", line 792, in cardinality
    raise exceptions.InfiniteLanguageException("The language represented by the DFA is infinite.")
automata.base.exceptions.InfiniteLanguageException: The language represented by the DFA is infinite.

Workaround

Manually copying the automaton works:

VisualDFA(states=dfa.states, input_symbols=dfa.input_symbols, transitions=dfa.transitions,
          initial_state=dfa.initial_state, final_states=dfa.final_states).show_diagram(view=True)

The VisualNFA constructor attempts to create a deep copy of the passed nfa, especially the transitions dictionary:

The deepcopy method is monkeypatched onto dict via curse:

However, automata-lib 7.0.1 returns a frozendict from the frozendict package instead, so the method call fails. It is not clear if copying the frozendict is at all necessary; deepcopy returns the object as-is.

MRE

Using most recent versions:

• automata-lib 7.0.1
• visual_automata 1.1.1

from automata.fa.nfa import NFA
from visual_automata.fa.nfa import VisualNFA

nfa = NFA(states={"q0"}, input_symbols={"i0"}, transitions={"q0": {"i0": {"q0"}}}, initial_state="q0",
          final_states={"q0"})
VisualNFA(nfa).show_diagram(view=True)

Expected Behavior

The automaton is shown.

Actual Behavior

Traceback (most recent call last):
  File "/path/to/scratch_1.py", line 6, in <module>
    VisualNFA(nfa).show_diagram(view=True)
  File "/path/to/site-packages/visual_automata/fa/nfa.py", line 619, in show_diagram
    all_transitions_pairs = self._transitions_pairs(self.nfa.transitions)
  File "/path/to/site-packages/visual_automata/fa/nfa.py", line 469, in _transitions_pairs
    all_transitions = all_transitions.deepcopy()
AttributeError: 'frozendict.frozendict' object has no attribute 'deepcopy'

Hey,

I cannot reproduce the example given from https://pypi.org/project/visual-automata/#visualdfa
Upon the call of VisualDFA(dfa) on the dfa

dfa = DFA(
states={"q0", "q1", "q2", "q3", "q4"},
input_symbols={"0", "1"},
transitions={
"q0": {"0": "q3", "1": "q1"},
"q1": {"0": "q3", "1": "q2"},
"q2": {"0": "q3", "1": "q2"},
"q3": {"0": "q4", "1": "q1"},
"q4": {"0": "q4", "1": "q1"},
},
initial_state="q0",
final_states={"q2", "q4"},
)

I get the following error:

InfiniteLanguageException: The language represented by the DFA is infinite.

I use the following versions:

automata-lib 8.0.0
visual-automata 1.1.1

Thanks for taking care already