ClickHouse/dbms/src/Parsers/ASTFunction.cpp

#include <DB/Parsers/ASTLiteral.h>
#include <DB/Parsers/ASTFunction.h>


namespace DB
{

void ASTFunction::formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
	/// Если есть алиас, то требуются скобки вокруг всего выражения, включая алиас. Потому что запись вида 0 AS x + 0 синтаксически некорректна.
	if (frame.need_parens && !alias.empty())
		settings.ostr << '(';

	FormatStateStacked nested_need_parens = frame;
	FormatStateStacked nested_dont_need_parens = frame;
	nested_need_parens.need_parens = true;
	nested_dont_need_parens.need_parens = false;

	/// Стоит ли записать эту функцию в виде оператора?
	bool written = false;
	if (arguments && !parameters)
	{
		if (arguments->children.size() == 1)
		{
			const char * operators[] =
			{
				"negate", "-",
				"not", "NOT ",
				nullptr
			};

			for (const char ** func = operators; *func; func += 2)
			{
				if (0 == strcmp(name.c_str(), func[0]))
				{
					settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");

					/** Особо дурацкий случай. Если у нас унарный минус перед литералом, являющимся отрицательным числом:
						* "-(-1)" или "- -1", то это нельзя форматировать как --1, так как это будет воспринято как комментарий.
						* Вместо этого, добавим пробел.
						* PS. Нельзя просто попросить добавить скобки - см. formatImpl для ASTLiteral.
						*/
					if (name == "negate" && typeid_cast<const ASTLiteral *>(&*arguments->children[0]))
						settings.ostr << ' ';

					FormatStateStacked nested_frame;
					nested_frame.need_parens = true;
					arguments->formatImpl(settings, state, nested_need_parens);
					written = true;
				}
			}
		}

		/** need_parens - нужны ли скобки вокруг выражения с оператором.
			* Они нужны, только если это выражение входит в другое выражение с оператором.
			*/

		if (!written && arguments->children.size() == 2)
		{
			const char * operators[] =
			{
				"multiply",			" * ",
				"divide",			" / ",
				"modulo",			" % ",
				"plus", 			" + ",
				"minus", 			" - ",
				"notEquals",		" != ",
				"lessOrEquals",		" <= ",
				"greaterOrEquals",	" >= ",
				"less",				" < ",
				"greater",			" > ",
				"equals",			" = ",
				"like",				" LIKE ",
				"notLike",			" NOT LIKE ",
				"in",				" IN ",
				"notIn",			" NOT IN ",
				"globalIn",			" GLOBAL IN ",
				"globalNotIn",		" GLOBAL NOT IN ",
				nullptr
			};

			for (const char ** func = operators; *func; func += 2)
			{
				if (0 == strcmp(name.c_str(), func[0]))
				{
					if (frame.need_parens)
						settings.ostr << '(';
					arguments->children[0]->formatImpl(settings, state, nested_need_parens);
					settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
					arguments->children[1]->formatImpl(settings, state, nested_need_parens);
					if (frame.need_parens)
						settings.ostr << ')';
					written = true;
				}
			}

			if (!written && 0 == strcmp(name.c_str(), "arrayElement"))
			{
				arguments->children[0]->formatImpl(settings, state, nested_need_parens);
				settings.ostr << (settings.hilite ? hilite_operator : "") << '[' << (settings.hilite ? hilite_none : "");
				arguments->children[1]->formatImpl(settings, state, nested_need_parens);
				settings.ostr << (settings.hilite ? hilite_operator : "") << ']' << (settings.hilite ? hilite_none : "");
				written = true;
			}

			if (!written && 0 == strcmp(name.c_str(), "tupleElement"))
			{
				arguments->children[0]->formatImpl(settings, state, nested_need_parens);
				settings.ostr << (settings.hilite ? hilite_operator : "") << "." << (settings.hilite ? hilite_none : "");
				arguments->children[1]->formatImpl(settings, state, nested_need_parens);
				written = true;
			}
		}

		if (!written && arguments->children.size() >= 2)
		{
			const char * operators[] =
			{
				"and",				" AND ",
				"or",				" OR ",
				nullptr
			};

			for (const char ** func = operators; *func; func += 2)
			{
				if (0 == strcmp(name.c_str(), func[0]))
				{
					if (frame.need_parens)
						settings.ostr << '(';
					for (size_t i = 0; i < arguments->children.size(); ++i)
					{
						if (i != 0)
							settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
						arguments->children[i]->formatImpl(settings, state, nested_need_parens);
					}
					if (frame.need_parens)
						settings.ostr << ')';
					written = true;
				}
			}
		}

		if (!written && arguments->children.size() >= 1 && 0 == strcmp(name.c_str(), "array"))
		{
			settings.ostr << (settings.hilite ? hilite_operator : "") << '[' << (settings.hilite ? hilite_none : "");
			for (size_t i = 0; i < arguments->children.size(); ++i)
			{
				if (i != 0)
					settings.ostr << ", ";
				arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
			}
			settings.ostr << (settings.hilite ? hilite_operator : "") << ']' << (settings.hilite ? hilite_none : "");
			written = true;
		}

		if (!written && arguments->children.size() >= 2 && 0 == strcmp(name.c_str(), "tuple"))
		{
			settings.ostr << (settings.hilite ? hilite_operator : "") << '(' << (settings.hilite ? hilite_none : "");
			for (size_t i = 0; i < arguments->children.size(); ++i)
			{
				if (i != 0)
					settings.ostr << ", ";
				arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
			}
			settings.ostr << (settings.hilite ? hilite_operator : "") << ')' << (settings.hilite ? hilite_none : "");
			written = true;
		}
	}

	if (!written)
	{
		settings.ostr << (settings.hilite ? hilite_function : "") << name;

		if (parameters)
		{
			settings.ostr << '(' << (settings.hilite ? hilite_none : "");
			parameters->formatImpl(settings, state, nested_dont_need_parens);
			settings.ostr << (settings.hilite ? hilite_function : "") << ')';
		}

		if (arguments)
		{
			settings.ostr << '(' << (settings.hilite ? hilite_none : "");
			arguments->formatImpl(settings, state, nested_dont_need_parens);
			settings.ostr << (settings.hilite ? hilite_function : "") << ')';
		}

		settings.ostr << (settings.hilite ? hilite_none : "");
	}

	if (!alias.empty())
	{
		writeAlias(alias, settings.ostr, settings.hilite);
		if (frame.need_parens)
			settings.ostr << ')';
	}
}

}