internal sealed override InternalResult <TToken> Parse(ref ParseState <TToken> state)
{
if (!state.HasCurrent)
{
state.Error = new InternalError <TToken>(
Maybe.Nothing <TToken>(),
true,
state.SourcePos,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <TToken>(false));
}
var token = state.Current;
if (!EqualityComparer <TToken> .Default.Equals(token, _token))
{
state.Error = new InternalError <TToken>(
Maybe.Just(token),
false,
state.SourcePos,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <TToken>(false));
}
state.Advance();
return(InternalResult.Success <TToken>(token, true));
}
internal sealed override InternalResult <T> Parse(ref ParseState <TToken> state)
{
state.BeginExpectedTran();
var result = _parser.Parse(ref state);
state.EndExpectedTran(!result.Success);
if (!result.Success)
{
return(result);
}
var val = result.Value;
if (!_predicate(val))
{
state.Error = new InternalError <TToken>(
Maybe.Nothing <TToken>(),
false,
state.Location,
_message(val)
);
state.AddExpected(_expected);
return(InternalResult.Failure <T>(result.ConsumedInput));
}
return(result);
}
internal sealed override InternalResult <string> Parse(ref ParseState <char> state)
{
var span = state.LookAhead(_value.Length); // span.Length <= _valueTokens.Length
var errorPos = -1;
for (var i = 0; i < span.Length; i++)
{
if (!char.ToLowerInvariant(span[i]).Equals(char.ToLowerInvariant(_value[i])))
{
errorPos = i;
break;
}
}
if (errorPos != -1)
{
// strings didn't match
state.Advance(errorPos);
state.Error = new InternalError <char>(
Maybe.Just(span[errorPos]),
false,
state.Location,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <string>(errorPos > 0));
}
if (span.Length < _value.Length)
{
// strings matched but reached EOF
state.Advance(span.Length);
state.Error = new InternalError <char>(
Maybe.Nothing <char>(),
true,
state.Location,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <string>(span.Length > 0));
}
// OK
state.Advance(_value.Length);
return(InternalResult.Success <string>(span.ToString(), _value.Length > 0));
}
internal sealed override InternalResult <TEnumerable> Parse(ref ParseState <TToken> state)
{
var span = state.LookAhead(_valueTokens.Length); // span.Length <= _valueTokens.Length
var errorPos = -1;
for (var i = 0; i < span.Length; i++)
{
if (!EqualityComparer <TToken> .Default.Equals(span[i], _valueTokens[i]))
{
errorPos = i;
break;
}
}
if (errorPos != -1)
{
// strings didn't match
state.Advance(errorPos);
state.Error = new InternalError <TToken>(
Maybe.Just(span[errorPos]),
false,
state.Location,
null
);
state.AddExpected(new Expected <TToken>(_valueTokens));
return(InternalResult.Failure <TEnumerable>(errorPos > 0));
}
if (span.Length < _valueTokens.Length)
{
// strings matched but reached EOF
state.Advance(span.Length);
state.Error = new InternalError <TToken>(
Maybe.Nothing <TToken>(),
true,
state.Location,
null
);
state.AddExpected(new Expected <TToken>(_valueTokens));
return(InternalResult.Failure <TEnumerable>(span.Length > 0));
}
// OK
state.Advance(_valueTokens.Length);
return(InternalResult.Success <TEnumerable>(_value, _valueTokens.Length > 0));
}
internal sealed override InternalResult <T> Parse(ref ParseState <TToken> state)
{
state.Error = new InternalError <TToken>(
Maybe.Nothing <TToken>(),
false,
state.SourcePos,
_message
);
state.AddExpected(_expected);
return(InternalResult.Failure <T>(false));
}
internal override InternalResult <T> Parse(ref ParseState <TToken> state)
{
state.BeginExpectedTran();
var result = _parser.Parse(ref state);
state.EndExpectedTran(false);
if (!result.Success)
{
state.AddExpected(_expected);
}
return(result);
}
internal sealed override InternalResult <string> Parse(ref ParseState <char> state)
{
var consumedInput = false;
var builder = new InplaceStringBuilder(_value.Length);
foreach (var c in _value)
{
if (!state.HasCurrent)
{
state.Error = new InternalError <char>(
Maybe.Nothing <char>(),
true,
state.SourcePos,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <string>(consumedInput));
}
var token = state.Current;
if (char.ToLowerInvariant(token) != char.ToLowerInvariant(c))
{
state.Error = new InternalError <char>(
Maybe.Just(token),
false,
state.SourcePos,
null
);
state.AddExpected(Expected);
return(InternalResult.Failure <string>(consumedInput));
}
consumedInput = true;
builder.Append(token);
state.Advance();
}
return(InternalResult.Success <string>(builder.ToString(), consumedInput));
}
// see comment about expecteds in ParseState.Error.cs
internal sealed override InternalResult <T> Parse(ref ParseState <TToken> state)
{
var firstTime = true;
var err = new InternalError <TToken>(
Maybe.Nothing <TToken>(),
false,
state.Location,
"OneOf had no arguments"
);
state.BeginExpectedTran();
foreach (var p in _parsers)
{
state.BeginExpectedTran();
var thisResult = p.Parse(ref state);
if (thisResult.Success)
{
// throw out all expecteds
state.EndExpectedTran(false);
state.EndExpectedTran(false);
return(thisResult);
}
// we'll usually return the error from the first parser that didn't backtrack,
// even if other parsers had a longer match.
// There is some room for improvement here.
if (thisResult.ConsumedInput)
{
// throw out all expecteds except this one
var expected = state.ExpectedTranState();
state.EndExpectedTran(false);
state.EndExpectedTran(false);
state.AddExpected(expected.AsSpan());
expected.Dispose(clearArray: true);
return(thisResult);
}
state.EndExpectedTran(true);
// choose the longest match, preferring the left-most error in a tie,
// except the first time (avoid returning "OneOf had no arguments").
if (firstTime || state.Error.ErrorLocation > err.ErrorLocation)
{
err = state.Error;
}
firstTime = false;
}
state.Error = err;
state.EndExpectedTran(true);
return(InternalResult.Failure <T>(false));
}
internal sealed override InternalResult <Unit> Parse(ref ParseState <TToken> state)
{
if (state.HasCurrent)
{
state.Error = new InternalError <TToken>(
Maybe.Just(state.Current),
false,
state.SourcePos,
null
);
state.AddExpected(new Expected <TToken>());
return(InternalResult.Failure <Unit>(false));
}
return(InternalResult.Success(Unit.Value, false));
}
// see comment about expecteds in ParseState.Error.cs
internal override InternalResult <IEnumerable <T> > Parse(ref ParseState <TToken> state)
{
var ts = _keepResults ? new List <T>() : null;
var firstItemResult = _parser.Parse(ref state);
if (!firstItemResult.Success)
{
// state.Error set by _parser
return(InternalResult.Failure <IEnumerable <T> >(firstItemResult.ConsumedInput));
}
if (!firstItemResult.ConsumedInput)
{
throw new InvalidOperationException("Until() used with a parser which consumed no input");
}
ts?.Add(firstItemResult.Value);
while (true)
{
state.BeginExpectedTran();
var terminatorResult = _terminator.Parse(ref state);
if (terminatorResult.Success)
{
state.EndExpectedTran(false);
return(InternalResult.Success <IEnumerable <T> >(ts, true));
}
if (terminatorResult.ConsumedInput)
{
// state.Error set by _terminator
state.EndExpectedTran(true);
return(InternalResult.Failure <IEnumerable <T> >(true));
}
state.BeginExpectedTran();
var itemResult = _parser.Parse(ref state);
if (!itemResult.Success)
{
if (!itemResult.ConsumedInput)
{
// get the expected from both _terminator and _parser
state.EndExpectedTran(true);
state.EndExpectedTran(true);
}
else
{
// throw out the _terminator expecteds and keep only _parser
var itemExpected = state.ExpectedTranState();
state.EndExpectedTran(false);
state.EndExpectedTran(false);
state.AddExpected(itemExpected.AsSpan());
itemExpected.Dispose();
}
return(InternalResult.Failure <IEnumerable <T> >(true));
}
// throw out both sets of expecteds
state.EndExpectedTran(false);
state.EndExpectedTran(false);
if (!itemResult.ConsumedInput)
{
throw new InvalidOperationException("Until() used with a parser which consumed no input");
}
ts?.Add(itemResult.Value);
}
}
