public void ProduceElement()
{
StringTransducer produce = StringTransducer.ProduceElement('x');
StringInferenceTestUtilities.TestTransducerValue(produce, string.Empty, "x", 1.0);
StringInferenceTestUtilities.TestTransducerValue(produce, string.Empty, "xx", 0.0);
StringInferenceTestUtilities.TestTransducerValue(produce, string.Empty, string.Empty, 0.0);
StringInferenceTestUtilities.TestTransducerValue(produce, "x", string.Empty, 0.0);
StringInferenceTestUtilities.TestTransducerValue(produce, "xx", string.Empty, 0.0);
}
/// <summary>
/// Creates a transducer that replaces braces surrounding the given argument placeholder
/// with <see cref="LeftBraceReplacer"/> and <see cref="RightBraceReplacer"/>.
/// </summary>
/// <param name="argument">The index of the argument.</param>
/// <param name="argumentCount">The total number of the arguments.</param>
/// <param name="transpose">Specifies whether the created transducer should be transposed (useful for backward message computation).</param>
/// <returns>The created transducer.</returns>
private static StringTransducer GetArgumentEscapingTransducer(int argument, int argumentCount, bool transpose)
{
Debug.Assert(argumentCount >= 1 && argumentCount <= 10, "Up to 10 arguments currently supported.");
Debug.Assert(argument >= 0 && argument < argumentCount, "Argument index must be less than the number of arguments.");
List <Pair <StringTransducer, StringTransducer> > argumentToEscapingTransducers;
if (!ArgumentCountToEscapingTransducers.TryGetValue(argumentCount, out argumentToEscapingTransducers))
{
argumentToEscapingTransducers = new List <Pair <StringTransducer, StringTransducer> >(argumentCount);
ArgumentCountToEscapingTransducers[argumentCount] = argumentToEscapingTransducers;
for (int i = 0; i < argumentCount; ++i)
{
// Escapes braces in {i}
StringTransducer replaceBracesForDigit = StringTransducer.ConsumeElement('{');
replaceBracesForDigit.AppendInPlace(StringTransducer.ProduceElement(LeftBraceReplacer));
replaceBracesForDigit.AppendInPlace(StringTransducer.CopyElement((char)('0' + i)));
replaceBracesForDigit.AppendInPlace(StringTransducer.ConsumeElement('}'));
replaceBracesForDigit.AppendInPlace(StringTransducer.ProduceElement(RightBraceReplacer));
// Skips any number of placeholders which differ from {i}, with arbitrary intermediate text
DiscreteChar noBraces = DiscreteChar.UniformOver('{', '}').Complement();
StringTransducer braceReplacer = StringTransducer.Copy(noBraces);
if (argumentCount > 1)
{
// Skips every placeholder except {i}
StringTransducer skipOtherDigits = StringTransducer.CopyElement('{');
skipOtherDigits.AppendInPlace(StringTransducer.CopyElement(AllDigitsExcept(i, argumentCount - 1)));
skipOtherDigits.AppendInPlace(StringTransducer.CopyElement('}'));
braceReplacer.AppendInPlace(skipOtherDigits);
braceReplacer = StringTransducer.Repeat(braceReplacer, minTimes: 0);
braceReplacer.AppendInPlace(StringTransducer.Copy(noBraces));
}
// Skips placeholders, then escapes {i} and skips placeholders
StringTransducer escapeAndSkip = replaceBracesForDigit.Clone();
escapeAndSkip.AppendInPlace(braceReplacer);
StringTransducer transducer = braceReplacer.Clone();
transducer.AppendInPlace(escapeAndSkip); // TODO: use Optional() here if {i} can be omitted
StringTransducer transducerTranspose = StringTransducer.Transpose(transducer);
argumentToEscapingTransducers.Add(Pair.Create(transducer, transducerTranspose));
}
}
return(transpose ? argumentToEscapingTransducers[argument].Second : argumentToEscapingTransducers[argument].First);
}
