Dialogs Program documentation     Error messages Formatting for numbers, currency, and dates     HeIp text and other on-line references Collation of string and numeric values

There are many varied character sets supported by computer technology in the world today. Applications that must run in different language environments or on different systems may have to deal with several character sets, some of which may not be known until runtime. To alleviate this problem, Galaxy defines three abstract character sets:

the vchar character set   the literal character set   the system character set

 

 

The vchar character set is used for all text processing in a Galaxy application. This is a fixed-width character set defined by the libraries. All Galaxy entry points that take a string as a parameter (other than string conversion entry points) expect a string in vchar character set. The vchar character set is bound to a real character set when Galaxy is built for a particular platform. The literal character set is the one in which the compiler generates string and character constants. It is determined based on the compiler and is also bound at build time. The system character set is the one understood by the operating system on which the Galaxy application is running. The system character set is used to pass strings directly to and from the operating system. It is also used internally by Galaxy in its interface to the system. The system character set is not known until runtime and may be a multibyte set.

To simplify the task of translating strings between different character sets, Galaxy provides conversion scribes. A scribe is a temporary object that contains the information necessary to write out a string in any desired format. It can serve as a translator between the available and the required representation of a string. If the two representations are identical, the conversion can be done with no work at all. If some conversion is required, it is done directly to the required representation: Scribes are very efficient because they encapsulate strings and minimize data copying and temporary dynamic storage.
Galaxy supports many character sets by name. Currently, Latin- 1, Macintosh Roman, and Unicode are supported as vchar character sets, while conversion scribes to and from the vchar character set are provided for strings encoded in other well known standards including:

Applications can take full advantage of the supported standards when the vchar character set is Unicode; graceful degradation occurs if they are compiled with a different vchar character set. For example, when the Drawing Manager draws strings, it uses the current font, and in the case of the Unicode vchar character set, it automatically converts from the vchar character set to the font’s encoding. If the current font does not contain a glyph for a particular character in the string, the Drawing Manager selects a related or otherwise suitable font for that particular character.

Galaxy provides predefined localized formats for textual representation of numbers, using the appropriate digit set, decimal point character, digit grouping, currency symbol, and other characteristics. Galaxy supports localized collation of strings using multi-level ordering, which is common in European languages. Galaxy follows standards wherever possible and will also support native string collation methods.

The Galaxy Text Manager uses the underlying window system’s input methods to allow input of various kinds of characters, such as the accented letters used in Europe and the ideographic characters of East-Asian languages.