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#include <mbgl/style/expression/collator.hpp>
#include <mbgl/style/expression/comparison.hpp>
#include <mbgl/style/expression/dsl.hpp>
namespace mbgl {
namespace style {
namespace expression {
static bool isComparableType(const std::string& op, const type::Type& type) {
if (op == "==" || op == "!=") {
return type == type::String ||
type == type::Number ||
type == type::Boolean ||
type == type::Null ||
type == type::Value;
} else {
return type == type::String ||
type == type::Number ||
type == type::Value;
}
}
bool eq(Value a, Value b) { return a == b; }
bool neq(Value a, Value b) { return a != b; }
bool lt(Value lhs, Value rhs) {
return lhs.match(
[&](const std::string& a) { return a < rhs.get<std::string>(); },
[&](double a) { return a < rhs.get<double>(); },
[&](const auto&) { assert(false); return false; }
);
}
bool gt(Value lhs, Value rhs) {
return lhs.match(
[&](const std::string& a) { return a > rhs.get<std::string>(); },
[&](double a) { return a > rhs.get<double>(); },
[&](const auto&) { assert(false); return false; }
);
}
bool lteq(Value lhs, Value rhs) {
return lhs.match(
[&](const std::string& a) { return a <= rhs.get<std::string>(); },
[&](double a) { return a <= rhs.get<double>(); },
[&](const auto&) { assert(false); return false; }
);
}
bool gteq(Value lhs, Value rhs) {
return lhs.match(
[&](const std::string& a) { return a >= rhs.get<std::string>(); },
[&](double a) { return a >= rhs.get<double>(); },
[&](const auto&) { assert(false); return false; }
);
}
bool eqCollate(std::string a, std::string b, Collator c) { return c.compare(a, b) == 0; }
bool neqCollate(std::string a, std::string b, Collator c) { return !eqCollate(a, b, c); }
bool ltCollate(std::string a, std::string b, Collator c) { return c.compare(a, b) < 0; }
bool gtCollate(std::string a, std::string b, Collator c) { return c.compare(a, b) > 0; }
bool lteqCollate(std::string a, std::string b, Collator c) { return c.compare(a, b) <= 0; }
bool gteqCollate(std::string a, std::string b, Collator c) { return c.compare(a, b) >= 0; }
static BasicComparison::CompareFunctionType getBasicCompareFunction(const std::string& op) {
if (op == "==") return eq;
else if (op == "!=") return neq;
else if (op == ">") return gt;
else if (op == "<") return lt;
else if (op == ">=") return gteq;
else if (op == "<=") return lteq;
assert(false);
return nullptr;
}
static CollatorComparison::CompareFunctionType getCollatorComparisonFunction(const std::string& op) {
if (op == "==") return eqCollate;
else if (op == "!=") return neqCollate;
else if (op == ">") return gtCollate;
else if (op == "<") return ltCollate;
else if (op == ">=") return gteqCollate;
else if (op == "<=") return lteqCollate;
assert(false);
return nullptr;
}
BasicComparison::BasicComparison(
std::string op_,
std::unique_ptr<Expression> lhs_,
std::unique_ptr<Expression> rhs_)
: Expression(Kind::Comparison, type::Boolean),
op(std::move(op_)),
compare(getBasicCompareFunction(op)),
lhs(std::move(lhs_)),
rhs(std::move(rhs_)) {
assert(isComparableType(op, lhs->getType()) && isComparableType(op, rhs->getType()));
assert(lhs->getType() == rhs->getType() || lhs->getType() == type::Value || rhs->getType() == type::Value);
needsRuntimeTypeCheck = (op != "==" && op != "!=") &&
(lhs->getType() == type::Value || rhs->getType() == type::Value);
}
EvaluationResult BasicComparison::evaluate(const EvaluationContext& params) const {
EvaluationResult lhsResult = lhs->evaluate(params);
if (!lhsResult) return lhsResult;
EvaluationResult rhsResult = rhs->evaluate(params);
if (!rhsResult) return rhsResult;
if (needsRuntimeTypeCheck) {
type::Type lhsType = typeOf(*lhsResult);
type::Type rhsType = typeOf(*rhsResult);
// check that type is string or number, and equal
if (lhsType != rhsType || !(lhsType == type::String || lhsType == type::Number)) {
return EvaluationError {
R"(Expected arguments for ")" + op + R"(")" +
" to be (string, string) or (number, number), but found (" + toString(lhsType) + ", " +
toString(rhsType) + ") instead."
};
}
}
return compare(*lhsResult, *rhsResult);
}
void BasicComparison::eachChild(const std::function<void(const Expression&)>& visit) const {
visit(*lhs);
visit(*rhs);
}
std::string BasicComparison::getOperator() const { return op; }
bool BasicComparison::operator==(const Expression& e) const {
if (e.getKind() == Kind::Comparison) {
auto comp = static_cast<const BasicComparison*>(&e);
return comp->op == op &&
*comp->lhs == *lhs &&
*comp->rhs == *rhs;
}
return false;
}
std::vector<optional<Value>> BasicComparison::possibleOutputs() const {
return {{ true }, { false }};
}
CollatorComparison::CollatorComparison(
std::string op_,
std::unique_ptr<Expression> lhs_,
std::unique_ptr<Expression> rhs_,
std::unique_ptr<Expression> collator_)
: Expression(Kind::Comparison, type::Boolean),
op(op_),
compare(getCollatorComparisonFunction(op)),
lhs(std::move(lhs_)),
rhs(std::move(rhs_)),
collator(std::move(collator_)) {
assert(isComparableType(op, lhs->getType()) && isComparableType(op, rhs->getType()));
assert(lhs->getType() == rhs->getType() || lhs->getType() == type::Value || rhs->getType() == type::Value);
needsRuntimeTypeCheck = (op == "==" || op == "!=") &&
(lhs->getType() == type::Value || rhs->getType() == type::Value);
}
EvaluationResult CollatorComparison::evaluate(const EvaluationContext& params) const {
EvaluationResult lhsResult = lhs->evaluate(params);
if (!lhsResult) return lhsResult;
EvaluationResult rhsResult = rhs->evaluate(params);
if (!rhsResult) return lhsResult;
if (needsRuntimeTypeCheck) {
if (typeOf(*lhsResult) != type::String || typeOf(*rhsResult) != type::String) {
return getBasicCompareFunction(op)(*lhsResult, *rhsResult);
}
}
auto collatorResult = collator->evaluate(params);
if (!collatorResult) return collatorResult;
const Collator& c = collatorResult->get<Collator>();
return compare(lhsResult->get<std::string>(), rhsResult->get<std::string>(), c);
}
void CollatorComparison::eachChild(const std::function<void(const Expression&)>& visit) const {
visit(*lhs);
visit(*rhs);
visit(*collator);
}
std::string CollatorComparison::getOperator() const { return op; }
bool CollatorComparison::operator==(const Expression& e) const {
if (e.getKind() == Kind::Comparison) {
auto comp = static_cast<const CollatorComparison*>(&e);
return comp->op == op &&
*comp->collator == *collator &&
*comp->lhs == *lhs &&
*comp->rhs == *rhs;
}
return false;
}
std::vector<optional<Value>> CollatorComparison::possibleOutputs() const {
return {{ true }, { false }};
}
using namespace mbgl::style::conversion;
ParseResult parseComparison(const Convertible& value, ParsingContext& ctx) {
std::size_t length = arrayLength(value);
if (length != 3 && length != 4) {
ctx.error("Expected two or three arguments.");
return ParseResult();
}
std::string op = *toString(arrayMember(value, 0));
assert(getBasicCompareFunction(op));
ParseResult lhs = ctx.parse(arrayMember(value, 1), 1, {type::Value});
if (!lhs) return ParseResult();
type::Type lhsType = (*lhs)->getType();
if (!isComparableType(op, lhsType)) {
ctx.error(R"(")" + op + R"(" comparisons are not supported for type ')" + toString(lhsType) + "'.", 1);
return ParseResult();
}
ParseResult rhs = ctx.parse(arrayMember(value, 2), 2, {type::Value});
if (!rhs) return ParseResult();
type::Type rhsType = (*rhs)->getType();
if (!isComparableType(op, rhsType)) {
ctx.error(R"(")" + op + R"(" comparisons are not supported for type ')" + toString(rhsType) + "'.", 2);
return ParseResult();
}
if (
lhsType != rhsType &&
lhsType != type::Value &&
rhsType != type::Value
) {
ctx.error("Cannot compare types '" + toString(lhsType) + "' and '" + toString(rhsType) + "'.");
return ParseResult();
}
if (op != "==" && op != "!=") {
// typing rules specific to less/greater than operators
if (lhsType == type::Value && rhsType != type::Value) {
// (value, T)
lhs = dsl::assertion(rhsType, std::move(*lhs));
} else if (lhsType != type::Value && rhsType == type::Value) {
// (T, value)
rhs = dsl::assertion(lhsType, std::move(*rhs));
}
}
if (length == 4) {
if (
lhsType != type::String &&
rhsType != type::String &&
lhsType != type::Value &&
rhsType != type::Value
) {
ctx.error("Cannot use collator to compare non-string types.");
return ParseResult();
}
ParseResult collatorParseResult = ctx.parse(arrayMember(value, 3), 3, {type::Collator});
if (!collatorParseResult) return ParseResult();
return ParseResult(std::make_unique<CollatorComparison>(op, std::move(*lhs), std::move(*rhs), std::move(*collatorParseResult)));
}
return ParseResult(std::make_unique<BasicComparison>(op, std::move(*lhs), std::move(*rhs)));
}
} // namespace expression
} // namespace style
} // namespace mbgl
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