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#pragma once
#include <algorithm>
#include <cctype>
#include <mbgl/style/conversion/get_json_type.hpp>
#include <mbgl/style/expression/parse.hpp>
#include <mbgl/style/expression/let.hpp>
#include <mbgl/style/expression/parsing_context.hpp>
#include <mbgl/style/expression/type.hpp>
#include <mbgl/style/conversion.hpp>
namespace mbgl {
namespace style {
namespace expression {
struct ParseLet {
static ParseResult parse(const mbgl::style::conversion::Value& value, ParsingContext ctx) {
using namespace mbgl::style::conversion;
assert(isArray(value));
std::size_t length = arrayLength(value);
if (length < 4) {
ctx.error("Expected at least 3 arguments, but found " + std::to_string(length - 1) + " instead.");
return ParseResult();
}
std::map<std::string, std::shared_ptr<Expression>> bindings;
for(std::size_t i = 1; i < length - 1; i += 2) {
optional<std::string> name = toString(arrayMember(value, i));
if (!name) {
ctx.error("Expected string, but found " + getJSONType(arrayMember(value, i)) + " instead.", i);
return ParseResult();
}
bool isValidName = std::all_of(name->begin(), name->end(), [](unsigned char c) {
return std::isalnum(c) || c == '_';
});
if (!isValidName) {
ctx.error("Variable names must contain only alphanumeric characters or '_'.", 1);
return ParseResult();
}
ParseResult bindingValue = parseExpression(arrayMember(value, i + 1), ParsingContext(ctx, i + 1));
if (!bindingValue) {
return ParseResult();
}
bindings.emplace(*name, std::move(*bindingValue));
}
auto resultContext = ParsingContext(ctx, length - 1, ctx.expected, bindings);
ParseResult result = parseExpression(arrayMember(value, length - 1), resultContext);
if (!result) {
return ParseResult();
}
return ParseResult(std::make_unique<Let>(std::move(bindings), std::move(*result)));
}
};
struct ParseVar {
static ParseResult parse(const mbgl::style::conversion::Value& value, ParsingContext ctx) {
using namespace mbgl::style::conversion;
assert(isArray(value));
if (arrayLength(value) != 2 || !toString(arrayMember(value, 1))) {
ctx.error("'var' expression requires exactly one string literal argument.");
return ParseResult();
}
std::string name = *toString(arrayMember(value, 1));
optional<std::shared_ptr<Expression>> bindingValue = ctx.getBinding(name);
if (!bindingValue) {
ctx.error(R"(Unknown variable ")" + name + R"(". Make sure ")" +
name + R"(" has been bound in an enclosing "let" expression before using it.)", 1);
return ParseResult();
}
return ParseResult(std::make_unique<Var>(name, std::move(*bindingValue)));
}
};
} // namespace expression
} // namespace style
} // namespace mbgl
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