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#pragma once
#include <mbgl/style/conversion.hpp>
#include <mbgl/style/expression/case.hpp>
#include <mbgl/style/expression/parsing_context.hpp>
#include <mbgl/style/expression/type.hpp>
namespace mbgl {
namespace style {
namespace expression {
struct ParseCase {
static ParseResult parse(const mbgl::style::conversion::Value& value, ParsingContext ctx) {
using namespace mbgl::style::conversion;
assert(isArray(value));
auto length = arrayLength(value);
if (length < 4) {
ctx.error("Expected at least 3 arguments, but found only " + std::to_string(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.expected && *ctx.expected != type::Value) {
outputType = ctx.expected;
}
std::vector<Case::Branch> branches;
for (size_t i = 1; i + 1 < length; i += 2) {
auto test = parseExpression(arrayMember(value, i), ParsingContext(ctx, i, {type::Boolean}));
if (!test) {
return test;
}
auto output = parseExpression(arrayMember(value, i + 1), ParsingContext(ctx, 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 = parseExpression(arrayMember(value, length - 1), ParsingContext(ctx, 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
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