diff options
Diffstat (limited to 'src/mbgl/style/expression/case.cpp')
-rw-r--r-- | src/mbgl/style/expression/case.cpp | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/mbgl/style/expression/case.cpp b/src/mbgl/style/expression/case.cpp new file mode 100644 index 0000000000..049f258606 --- /dev/null +++ b/src/mbgl/style/expression/case.cpp @@ -0,0 +1,91 @@ +#include <mbgl/style/expression/case.hpp> +#include <mbgl/util/string.hpp> + +namespace mbgl { +namespace style { +namespace expression { + +EvaluationResult Case::evaluate(const EvaluationContext& params) const { + for (const auto& branch : branches) { + const EvaluationResult evaluatedTest = branch.first->evaluate(params); + if (!evaluatedTest) { + return evaluatedTest.error(); + } + if (evaluatedTest->get<bool>()) { + return branch.second->evaluate(params); + } + } + + return otherwise->evaluate(params); +} + +void Case::eachChild(const std::function<void(const Expression&)>& visit) const { + for (const Branch& branch : branches) { + visit(*branch.first); + visit(*branch.second); + } + visit(*otherwise); +} + +bool Case::operator==(const Expression& e) const { + if (auto rhs = dynamic_cast<const Case*>(&e)) { + return *otherwise == *(rhs->otherwise) && Expression::childrenEqual(branches, rhs->branches); + } + return false; +} + +using namespace mbgl::style::conversion; +ParseResult Case::parse(const Convertible& value, ParsingContext& ctx) { + assert(isArray(value)); + auto length = arrayLength(value); + if (length < 4) { + ctx.error("Expected at least 3 arguments, but found only " + util::toString(length - 1) + "."); + return ParseResult(); + } + + // Expect even-length array: ["case", 2 * (n pairs)..., otherwise] + if (length % 2 != 0) { + ctx.error("Expected an odd number of arguments"); + return ParseResult(); + } + + optional<type::Type> outputType; + if (ctx.getExpected() && *ctx.getExpected() != type::Value) { + outputType = ctx.getExpected(); + } + + std::vector<Case::Branch> branches; + branches.reserve((length - 2) / 2); + for (size_t i = 1; i + 1 < length; i += 2) { + auto test = ctx.parse(arrayMember(value, i), i, {type::Boolean}); + if (!test) { + return test; + } + + auto output = ctx.parse(arrayMember(value, i + 1), i + 1, outputType); + if (!output) { + return output; + } + + if (!outputType) { + outputType = (*output)->getType(); + } + + branches.push_back(std::make_pair(std::move(*test), std::move(*output))); + } + + assert(outputType); + + auto otherwise = ctx.parse(arrayMember(value, length - 1), length - 1, outputType); + if (!otherwise) { + return otherwise; + } + + return ParseResult(std::make_unique<Case>(*outputType, + std::move(branches), + std::move(*otherwise))); +} + +} // namespace expression +} // namespace style +} // namespace mbgl |