In class, we implemented FSA by making state, initial, final, and arc basic facts in the database. Let's do an implementation now where these are structures. We will ultimately write a function go/3 that takes three arguments: a specification of an FSA (as described below), a state, and a string. The function returns true or false depending on whether the string is accepted from that state.

Here's an example:

go( fsa( initial(1), final([3]), arcs([ arc(1,a,2), arc(2,b,3), arc(2,b,2) ]) ), 1, "abbb").

The logic of the approach is that go/3 will look at that first argument, rather than facts in the database.

The first step, however, is to write a function that will extract the initial state from such an FSA representation getinitial/2. The first argument is an FSA representation like above and the second is the output.

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%%CONSULT%Your code here

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getinitial(fsa(initial(33),final([]),arcs([])),33).

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getinitial(fsa(initial(7),final([]),arcs([])),7).