CODEWITHSUNDEEP
xmlgrammarcontext-free-grammarw3c
David542
David542

Reputation: 110382

Examples of various XML definitions

In reading the XML spec, it mentions the following definitions:

Names and Tokens
[4]     NameStartChar      ::=      ":" | [A-Z] | "_" | [a-z] | [#xC0-#xD6] | [#xD8-#xF6] | [#xF8-#x2FF] | [#x370-#x37D] | [#x37F-#x1FFF] | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]
[4a]    NameChar           ::=      NameStartChar | "-" | "." | [0-9] | #xB7 | [#x0300-#x036F] | [#x203F-#x2040]
[5]     Name               ::=      NameStartChar (NameChar)*

Literals
[9]     EntityValue        ::=      '"' ([^%&"] | PEReference | Reference)* '"' |  "'" ([^%&'] | PEReference | Reference)* "'"
[10]    AttValue           ::=      '"' ([^<&"] | Reference)* '"'|  "'" ([^<&'] | Reference)* "'"
[11]    SystemLiteral      ::=      ('"' [^"]* '"') | ("'" [^']* "'")
[12]    PubidLiteral       ::=      '"' PubidChar* '"' | "'" (PubidChar - "'")* "'"
[13]    PubidChar          ::=      #x20 | #xD | #xA | [a-zA-Z0-9] | [-'()+,./:=?;!*#@$_%]

What would be an example of a Name vs. an Entity vs an Attribute vs a SystemLiteral vs a Pubid (?)

For example in the below:

<Item id="123">Hello<Item/>

Is Item the Name or the EntityValue? And I would assume that 123 or "123" would be the Att(ribute)Value. Are those both correct? What would be examples of the others?

From the spec it says:

Literal data is any quoted string not containing the quotation mark used as a delimiter for that string. Literals are used for specifying the content of internal entities (EntityValue), the values of attributes (AttValue), and external identifiers (SystemLiteral).

So from that I would think Item would be the EntityValue, 123 would be the AttrValue: what would be examples of a PubID and SystemLiteral then? Finally, why doesn't the EntityValue exclude the < and > chars?

Upvotes: 1

Views: 99

Answers (1)

kjhughes
kjhughes

Reputation: 111696

Your XML example is parsed as follows:

<Item id="123">Hello<Item/> is an element:

There are none of the following constructs in your example:

  • EntityValue
    Example: "2020" in <!ENTITY year "2020">
  • PubidLiteral
    Example: "-//W3C//DTD HTML 4.01//EN" in <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> )
  • SystemLiteral
    Example: "../img/logo.gif" in <!ENTITY logo SYSTEM "../img/logo.gif" NDATA gif >

See section 4.2 Entity Declarations for more context on how EntityValue, PubidLiteral, and SystemLiteral are used.

Upvotes: 3

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