public INfaVM Visit(RepeatNode node, INfaVM code)
{
for (int i = node.MinCount; i != 0; --i)
{
node.Inner.Accept(this, code);
}
if (node.MaxCount == int.MaxValue)
{
var start = code.Labels.Generate();
var end = code.Labels.Generate();
code.Label(start);
code.Fork(end.GetRef());
node.Inner.Accept(this, code);
code.Jmp(start.GetRef());
code.Label(end);
}
else
{
int optionalCount = node.MaxCount - node.MinCount;
while (optionalCount-- != 0)
{
var end = code.Labels.Generate();
code.Fork(end.GetRef());
node.Inner.Accept(this, code);
code.Label(end);
}
}
return(code);
}
public TextWriter Visit(RepeatNode node)
{
NewLine();
writer.Write("repeat from={0} to={1}:", node.MinCount, node.MaxCount);
IncreaseIndent();
try
{
node.Inner.Accept(this);
}
finally
{
DecreaseIndent();
}
return(writer);
}
public NfaFragment Visit(RepeatNode node)
{
// TODO: Replace Range with repeat
IEnumerable <NfaFragment> required
= Enumerable
.Range(0, node.MinCount)
.Select(_ => Build(node.Inner));
IEnumerable <NfaFragment> optional;
if (node.MaxCount != int.MaxValue)
{
optional = Enumerable
.Range(0, node.MaxCount - node.MinCount)
.Select(_ => NfaFragment.ZeroOrOne(Build(node.Inner)));
}
else
{
optional = new [] { NfaFragment.ZeroOrMore(Build(node.Inner)) };
}
return(NfaFragment.Cat(required.Concat(optional)));
}