iso - 什么是扩展 7 位(或 8 位)代码？

Question

我刚开始阅读 ECMA-48 standard (ISO/IEC 6429)，并提出问题。

它说:

This Ecma Standard defines control functions and their coded representations for use in a 7-bit code, an extended 7-bit code, an 8-bit code or an extended 8-bit code.

这里的“扩展”7/8 位代码是什么意思？

Answer 1

ECMA-35 讨论了这些。这些术语是关键:

code extension: The techniques for the encoding of characters that are not included in the character set of a given code.

escape sequence: A string of bit combinations that is used for control purposes in code extension procedures. The first of these bit combinations represents the control function ESCAPE.

Character ESCAPE: ESCAPE is a control character used for code extension purposes. It causes the meaning of a limited number of the bit combinations following it in a CC-data-element to be changed. These bit combinations, together with the preceding bit combination that represents the ESC character, constitute an escape sequence.

因此，我们这里有一个系统，您可以在文本中间切换编码系统:您可以使用 Latin-1 编码开始文本，提供一个切换到 Latin-2 的转义序列，然后继续您的文本。 ECMA-35 在附录 A 中对此进行了讨论。第 13 章提供了有关转义序列结构的更多信息。