// creates all combinations of symbols up to length given by lookaheadWidth
// example: A, B, C, up to 2
// will give: (empty), A, B, C, AA, AB, AC, BA, BB, BC, CA, CB, CC
public static SymbolChunkSet <SYMBOL_ENUM> MultiplyUpTo <SYMBOL_ENUM>(IEnumerable <SYMBOL_ENUM> symbols,
int lookaheadWidth)
where SYMBOL_ENUM : struct
{
var seed = SymbolChunkSet.Create(symbols.Select(it => SymbolChunk.Create(it)));
var working = new SymbolChunkSet <SYMBOL_ENUM>();
var result = new SymbolChunkSet <SYMBOL_ENUM>();
result.Add(SymbolChunk.Create <SYMBOL_ENUM>()); // empty entry
foreach (var _ in Enumerable.Repeat(0, lookaheadWidth))
{
working = MultiConcat(new[] { working, seed }, lookaheadWidth);
result.Add(working);
}
return(result);
}
public static IEnumerable <SymbolChunk <SYMBOL_ENUM> > MultiConcat <SYMBOL_ENUM>(SymbolChunk <SYMBOL_ENUM> chunk,
SymbolChunkSet <SYMBOL_ENUM> tailSet,
int limitLength)
where SYMBOL_ENUM : struct
{
if (chunk.Count >= limitLength)
{
yield return(chunk.GetFirst(limitLength));
}
else
{
foreach (SymbolChunk <SYMBOL_ENUM> tail_chunk in tailSet.Chunks)
{
yield return(chunk.Concat(tail_chunk, limitLength));
}
}
}