Plain Text - Plain Text, The Unicode Definition

Plain Text, The Unicode Definition

• «Plain text represents the basic, interchangeable content of text.»
• «Plain text represents character content only, not its appearance. »
• «It can be displayed in a variety of ways and requires a rendering process to make it visible with a particular appearance.»
• «If the same plain text sequence is given to disparate rendering processes, there is no expectation that rendered text in each instance should have the same appearance. »
• «Instead, the disparate rendering processes are simply required to make the text legible according to the intended reading. »
• «This legibility criterion constrains the range of possible appearances. »
• «The relationship between appearance and content of plain text may be summarized as follows: Plain text must contain enough information to permit the text to be rendered legibly, and nothing more.»
• «The Unicode Standard encodes plain text.»
• «The distinction between plain text and other forms of data in the same data stream is the function of a higher-level protocol and is not specified by the Unicode Standard itself.».

More formally, the fundamental distinction of "plain text" is that no information would be lost if you went through and translated the file to a completely different character encoding, or translated it to no encoding by just printing it out generically (provided the printer has a good enough font that you can correctly distinguish all the characters!). No information is conveyed by the fact that an "A" in the printout was originally stored as a byte with value 65 (as it would be in ASCII), or with value 193 (as in EBCDIC); and it certainly wasn't meant to express half of the bits of an integer.