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#pragma once
#include <mbgl/util/optional.hpp>
#include <mbgl/style/expression/type.hpp>
#include <mbgl/style/conversion.hpp>
#include <map>
#include <string>
#include <vector>
#include <memory>
namespace mbgl {
namespace style {
namespace expression {
class Expression;
struct ParsingError {
std::string message;
std::string key;
bool operator==(const ParsingError& rhs) const { return message == rhs.message && key == rhs.key; }
};
using ParseResult = optional<std::unique_ptr<Expression>>;
namespace detail {
class Scope {
public:
Scope(const std::map<std::string, std::shared_ptr<Expression>>& bindings_, std::shared_ptr<Scope> parent_ = nullptr) :
bindings(bindings_),
parent(std::move(parent_))
{}
const std::map<std::string, std::shared_ptr<Expression>>& bindings;
std::shared_ptr<Scope> parent;
optional<std::shared_ptr<Expression>> get(const std::string& name) {
auto it = bindings.find(name);
if (it != bindings.end()) {
return {it->second};
} else if (parent) {
return parent->get(name);
} else {
return optional<std::shared_ptr<Expression>>();
}
}
};
} // namespace detail
class ParsingContext {
public:
ParsingContext() : errors(std::make_shared<std::vector<ParsingError>>()) {}
ParsingContext(std::string key_) : key(std::move(key_)), errors(std::make_shared<std::vector<ParsingError>>()) {}
explicit ParsingContext(optional<type::Type> expected_)
: expected(std::move(expected_)),
errors(std::make_shared<std::vector<ParsingError>>())
{}
ParsingContext(ParsingContext&&) = default;
ParsingContext(const ParsingContext&) = delete;
ParsingContext& operator=(const ParsingContext&) = delete;
std::string getKey() const { return key; }
optional<type::Type> getExpected() const { return expected; }
const std::vector<ParsingError>& getErrors() const { return *errors; }
/*
Parse the given style-spec JSON value into an Expression object.
Specifically, this function is responsible for determining the expression
type (either Literal, or the one named in value[0]) and dispatching to the
appropriate ParseXxxx::parse(const V&, ParsingContext) method.
*/
ParseResult parse(const mbgl::style::conversion::Convertible& value);
/*
Parse a child expression.
*/
ParseResult parse(const mbgl::style::conversion::Convertible&,
std::size_t,
optional<type::Type> = {});
/*
Parse a child expression.
*/
ParseResult parse(const mbgl::style::conversion::Convertible&,
std::size_t index,
optional<type::Type>,
const std::map<std::string, std::shared_ptr<Expression>>&);
/*
Check whether `t` is a subtype of `expected`, collecting an error if not.
*/
optional<std::string> checkType(const type::Type& t);
optional<std::shared_ptr<Expression>> getBinding(const std::string name) {
if (!scope) return optional<std::shared_ptr<Expression>>();
return scope->get(name);
}
void error(std::string message) {
errors->push_back({message, key});
}
void error(std::string message, std::size_t child) {
errors->push_back({message, key + "[" + std::to_string(child) + "]"});
}
void error(std::string message, std::size_t child, std::size_t grandchild) {
errors->push_back({message, key + "[" + std::to_string(child) + "][" + std::to_string(grandchild) + "]"});
}
void appendErrors(ParsingContext&& ctx) {
errors->reserve(errors->size() + ctx.errors->size());
std::move(ctx.errors->begin(), ctx.errors->end(), std::inserter(*errors, errors->end()));
ctx.errors->clear();
}
void clearErrors() {
errors->clear();
}
private:
ParsingContext(std::string key_,
std::shared_ptr<std::vector<ParsingError>> errors_,
optional<type::Type> expected_,
std::shared_ptr<detail::Scope> scope_)
: key(std::move(key_)),
expected(std::move(expected_)),
scope(std::move(scope_)),
errors(std::move(errors_))
{}
std::string key;
optional<type::Type> expected;
std::shared_ptr<detail::Scope> scope;
std::shared_ptr<std::vector<ParsingError>> errors;
};
using ParseFunction = ParseResult (*)(const conversion::Convertible&, ParsingContext&);
using ExpressionRegistry = std::unordered_map<std::string, ParseFunction>;
const ExpressionRegistry& getExpressionRegistry();
} // namespace expression
} // namespace style
} // namespace mbgl
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