C++ Mapping for Constants
Slice constant definitions map to corresponding C++ constant definitions. For example:
const bool AppendByDefault = true;
const byte LowerNibble = 0x0f;
const string Advice = "Don't Panic!";
const short TheAnswer = 42;
const double PI = 3.1416;
enum Fruit { Apple, Pear, Orange };
const Fruit FavoriteFruit = Pear;
Here are the generated definitions for these constants:
const bool AppendByDefault = true;
const Ice::Byte LowerNibble = 15;
const std::string Advice = "Don't Panic!";
const Ice::Short TheAnswer = 42;
const Ice::Double PI = 3.1416;
enum Fruit { Apple, Pear, Orange };
const Fruit FavoriteFruit = Pear;
All constants are initialized directly in the header file, so they are compile-time constants and can be used in contexts where a compile-time constant expression is required, such as to dimension an array or as the case label of a switch statement.
A Slice string literal that contains non-ASCII characters is mapped by default to a narrow C++ string literal with the non-ASCII characters replaced by their UTF-8 encoding in octal escapes. For example:
const string Egg = "œuf";
is mapped to:
const std::string Egg = "\305\223uf";
If you map a string constant to a std::wstring, the non-ASCII characters in the string literal are replaced by universal character names, except for non-ASCII characters in the range \u0000 to \u009f that are replaced by octal escapes with the same value. For example:
const ["cpp:type:wstring"] string LargeEgg = "gros œuf";
is mapped to:
const std::wstring LargeEgg = L"gros \u0153uf";
Likewise, a Slice string literal that contains universal character names is mapped to a narrow C++ string with the universal character names replaced by their UTF-8 encoding in octal escapes, or to a wide C++ string with the universal character names preserved (except for characters in the range \u0000 to \u009f that are replaced by octal escapes with the same value). For example:
const string Heart = "c\u0153ur"; const ["cpp:type:wstring"] string BigHeart = "grand c\u0153ur"; const ["cpp:type:wstring"] string Banana = "\U0001F34C"; const string DoubleTilde = "~\u007e"; const ["cpp:type:wstring"] string WDoubleTilde = "~\u007e";
is mapped to:
const std::string Heart = "c\305\223ur"; const std::wstring BigHeart = L"grand c\u0153ur"; const std::wstring Banana = L"\U0001F34C"; const std::string DoubleTilde = "~\176"; const std::string WDoubleTilde = L"~\176";