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// © 2024 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
#include "unicode/utypes.h"
#ifndef U_HIDE_DEPRECATED_API
#ifndef MESSAGEFORMAT2_EVALUATION_H
#define MESSAGEFORMAT2_EVALUATION_H
#if U_SHOW_CPLUSPLUS_API
/**
* \file
* \brief C++ API: Formats messages using the draft MessageFormat 2.0.
*/
#if !UCONFIG_NO_FORMATTING
#if !UCONFIG_NO_MF2
#include "unicode/messageformat2_arguments.h"
#include "unicode/messageformat2_data_model.h"
#include "unicode/messageformat2_function_registry.h"
#include "messageformat2_errors.h"
// Auxiliary data structures used during formatting a message
U_NAMESPACE_BEGIN
namespace message2 {
using namespace data_model;
// PrioritizedVariant
// For how this class is used, see the references to (integer, variant) tuples
// in https://github.com/unicode-org/message-format-wg/blob/main/spec/formatting.md#pattern-selection
class PrioritizedVariant : public UObject {
public:
PrioritizedVariant() = default;
PrioritizedVariant(PrioritizedVariant&&) = default;
PrioritizedVariant& operator=(PrioritizedVariant&&) noexcept = default;
UBool operator<(const PrioritizedVariant&) const;
int32_t priority;
/* const */ SelectorKeys keys;
/* const */ Pattern pat;
PrioritizedVariant(uint32_t p,
const SelectorKeys& k,
const Pattern& pattern) noexcept : priority(p), keys(k), pat(pattern) {}
virtual ~PrioritizedVariant();
}; // class PrioritizedVariant
static inline int32_t comparePrioritizedVariants(UElement left, UElement right) {
const PrioritizedVariant& tuple1 = *(static_cast<const PrioritizedVariant*>(left.pointer));
const PrioritizedVariant& tuple2 = *(static_cast<const PrioritizedVariant*>(right.pointer));
if (tuple1 < tuple2) {
return -1;
}
if (tuple1.priority == tuple2.priority) {
return 0;
}
return 1;
}
// Encapsulates a value to be scrutinized by a `match` with its resolved
// options and the name of the selector
class ResolvedSelector : public UObject {
public:
ResolvedSelector() {}
ResolvedSelector(const FunctionName& fn,
Selector* selector,
FunctionOptions&& options,
FormattedPlaceholder&& value);
// Used either for errors, or when selector isn't yet known
explicit ResolvedSelector(FormattedPlaceholder&& value);
bool hasSelector() const { return selector.isValid(); }
const FormattedPlaceholder& argument() const { return value; }
FormattedPlaceholder&& takeArgument() { return std::move(value); }
const Selector* getSelector() {
U_ASSERT(selector.isValid());
return selector.getAlias();
}
FunctionOptions&& takeOptions() {
return std::move(options);
}
const FunctionName& getSelectorName() const { return selectorName; }
virtual ~ResolvedSelector();
ResolvedSelector& operator=(ResolvedSelector&&) noexcept;
ResolvedSelector(ResolvedSelector&&);
private:
FunctionName selectorName; // For error reporting
LocalPointer<Selector> selector;
FunctionOptions options;
FormattedPlaceholder value;
}; // class ResolvedSelector
// Closures and environments
// -------------------------
class Environment;
// A closure represents the right-hand side of a variable
// declaration, along with an environment giving values
// to its free variables
class Closure : public UMemory {
public:
const Expression& getExpr() const {
return expr;
}
const Environment& getEnv() const {
return env;
}
Closure(const Expression& expression, const Environment& environment) : expr(expression), env(environment) {}
Closure(Closure&&) = default;
virtual ~Closure();
private:
// An unevaluated expression
const Expression& expr;
// The environment mapping names used in this
// expression to other expressions
const Environment& env;
};
// An environment is represented as a linked chain of
// non-empty environments, terminating at an empty environment.
// It's searched using linear search.
class Environment : public UMemory {
public:
virtual bool has(const VariableName&) const = 0;
virtual const Closure& lookup(const VariableName&) const = 0;
static Environment* create(UErrorCode&);
static Environment* create(const VariableName&, Closure&&, Environment*, UErrorCode&);
virtual ~Environment();
};
class NonEmptyEnvironment;
class EmptyEnvironment : public Environment {
public:
EmptyEnvironment() = default;
virtual ~EmptyEnvironment();
private:
friend class Environment;
bool has(const VariableName&) const override;
const Closure& lookup(const VariableName&) const override;
static EmptyEnvironment* create(UErrorCode&);
static NonEmptyEnvironment* create(const VariableName&, Closure&&, Environment*, UErrorCode&);
};
class NonEmptyEnvironment : public Environment {
private:
friend class Environment;
bool has(const VariableName&) const override;
const Closure& lookup(const VariableName&) const override;
static NonEmptyEnvironment* create(const VariableName&, Closure&&, const Environment*, UErrorCode&);
virtual ~NonEmptyEnvironment();
private:
friend class Environment;
NonEmptyEnvironment(const VariableName& v, Closure&& c, Environment* e) : var(v), rhs(std::move(c)), parent(e) {}
// Maps VariableName onto Closure*
// Chain of linked environments
VariableName var;
Closure rhs;
const LocalPointer<Environment> parent;
};
// The context contains all the information needed to process
// an entire message: arguments, formatter cache, and error list
class MessageContext : public UMemory {
public:
MessageContext(const MessageArguments&, const StaticErrors&, UErrorCode&);
const Formattable* getGlobal(const VariableName&, UErrorCode&) const;
// If any errors were set, update `status` accordingly
void checkErrors(UErrorCode& status) const;
DynamicErrors& getErrors() { return errors; }
virtual ~MessageContext();
private:
const MessageArguments& arguments; // External message arguments
// Errors accumulated during parsing/formatting
DynamicErrors errors;
}; // class MessageContext
} // namespace message2
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_MF2 */
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif /* U_SHOW_CPLUSPLUS_API */
#endif // MESSAGEFORMAT2_EVALUATION_H
#endif // U_HIDE_DEPRECATED_API
// eof
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