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What is the "meaning" of an XML entity? of a character entity?

• From: Roger L Costello <costello@mitre.org>
• To: "xml-dev@lists.xml.org" <xml-dev@lists.xml.org>
• Date: Thu, 19 May 2022 10:25:38 +0000

Hi Folks,

Consider this XML entity:

	&

What is its meaning?

Answer: its meaning is & and & is literal syntax.

The meaning of this character entity:

	A

is A and A is literal syntax.

Recall that in a parser there are two stages to processing an input string:

input string --> lexical analysis (lexer) --> syntax analysis (parser)

The lexer groups the characters in the input string into tokens and sends the tokens to the parser.

Flex is a lexer-generator, i.e., the output of Flex is a lexer.

In the Flex manual [1] it recommends on page 76 that a lexer be designed to send the meaning of an entity to the parser, not the literal syntax, i.e.,

& --> lexer --> & --> parser

Pretty interesting, I think.

/Roger

[1] Flex manual is here: https://epaperpress.com/lexandyacc/download/flex.pdf

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  • Re: What is the "meaning" of an XML entity? of a character entity?
    • From: David Carlisle <d.p.carlisle@gmail.com>