// If nfa1 has form s1s ----> s1e
// and nfa2 has form s2s ----> s2e
// then nfa0 has form s0s -eps-> s1s ----> s1e -eps-> s0e
// s0s -eps-> s2s ----> s2e -eps-> s0e
public override Nfa MkNfa(Nfa.NameSource names)
{
var nfa1 = _r1.MkNfa(names);
var nfa2 = _r2.MkNfa(names);
var s0s = names.Next();
var s0e = names.Next();
var nfa0 = new Nfa(s0s, s0e);
foreach (var entry in nfa1.Trans)
{
nfa0.AddTrans(entry);
}
foreach (var entry in nfa2.Trans)
{
nfa0.AddTrans(entry);
}
nfa0.AddTrans(s0s, null, nfa1.Start);
nfa0.AddTrans(s0s, null, nfa2.Start);
nfa0.AddTrans(nfa1.Exit, null, s0e);
nfa0.AddTrans(nfa2.Exit, null, s0e);
return(nfa0);
}
// The resulting nfa0 has form s0s -sym-> s0e
public override Nfa MkNfa(Nfa.NameSource names)
{
var s0s = names.Next();
var s0e = names.Next();
var nfa0 = new Nfa(s0s, s0e);
nfa0.AddTrans(s0s, _sym, s0e);
return(nfa0);
}