// General convention in parsing methods: All whitespaces are consumed immediately after advancing the position.
// Methods can assume they do not need to advance past whitespace when they are called.
#region Parsing methods
private RootFilter ParseRootFilter()
{
bool includeDependents = false;
// Parse dependency selection. This may only be specified at the beginning of the root filter, outside any grouping
if (MatchesNext(LegacyDependentsFlag))
{
includeDependents = true;
m_position++;
}
SkipWhitespace();
PipFilter filter = ParseExpression();
if (includeDependents)
{
filter = new DependentsFilter(filter);
}
return(new RootFilter(filter, m_expression));
}
private PipFilter ParseFilterGroup()
{
string matched;
if (TryMatch(DependentsFunction, out matched) ||
TryMatch(DependenciesFunction, out matched) ||
TryMatch(RequiredInputsFunction, out matched) ||
TryMatch(CopyDependentsFunction, out matched))
{
AdvancePast(matched);
SkipWhitespace();
// Filter functions (i.e. dpt) is only allowed outside of group operators (). Check that the next character is the start
// of a group but don't consume is since that is handled by the recursive call
if (!MatchesNext(StartGroup))
{
throw CreateException(ErrorMessages.FilterFunctionMustBeOustideOfGroupDelimiters, StartGroup, EndGroup, DependentsFunction);
}
PipFilter result = ParseFilterGroup();
switch (matched)
{
case DependentsFunction:
result = new DependentsFilter(result);
break;
case DependenciesFunction:
result = new DependenciesFilter(result);
break;
case RequiredInputsFunction:
result = new DependenciesFilter(result, ClosureMode.DirectExcludingSelf);
break;
case CopyDependentsFunction:
default:
Contract.Assert(matched == CopyDependentsFunction, "Unexpected match");
result = new CopyDependentsFilter(result);
break;
}
return(result);
}
else if (MatchesNext(Negation))
{
ExpectAndAdvancePast(Negation);
SkipWhitespace();
// Negation is only allowed outside of group operators (). Check that the next character is the start
// of a group but don't consume is since that is handled by the recursive call
if (!MatchesNext(StartGroup))
{
throw CreateException(ErrorMessages.NetagionMustBeOustideOfGroupDelimiters, StartGroup, EndGroup);
}
PipFilter result = ParseFilterGroup();
result = result.Negate();
return(result);
}
else if (MatchesNext(StartGroup))
{
ExpectAndAdvancePast(StartGroup);
SkipWhitespace();
PipFilter result = ParseExpression();
ExpectAndAdvancePast(EndGroup);
SkipWhitespace();
return(result);
}
else
{
return(ParseFilterTuple());
}
}