第047回_intSubset

2.8 Prolog and Document Type Declaration
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[28b] intSubset ::= ( markupdecl | DeclSep )*
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Parameter entity references are recognized anywhere in the DTD (internal and external subsets and external parameter entities), except in literals, processing instructions, comments, and the contents of ignored conditional sections (see 3.4 Conditional Sections). They are also recognized in entity value literals. The use of parameter entities in the internal subset is restricted as described below.
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Well-formedness constraint: PEs in Internal Subset
In the internal DTD subset, parameter-entity references must not occur within markup declarations; they may occur where markup declarations can occur. (This does not apply to references that occur in external parameter entities or to the external subset.)

2.8 プロローグと文書型宣言