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     SECTION 3.2                                                                Objects



3.1.2 Comments

     Any occurrence of the percent sign character (%) outside a string or stream
     introduces a comment. The comment consists of all characters between the
     percent sign and the end of the line, including regular, delimiter, space, and tab
     characters. PDF ignores comments, treating them as if they were single white-
     space characters. That is, a comment separates the token preceding it from the
     one following it; thus, the PDF fragment

        abc% comment { /% ) blah blah blah
        123

     is syntactically equivalent to just the tokens abc and 123.

     Comments (other than the %PDF−n.m and %%EOF comments described in
     Section 3.4, “File Structure”) have no semantics. They are not necessarily
     preserved by applications that edit PDF files (see implementation note 2 in
     Appendix H). In particular, there is no PDF equivalent of the PostScript
     document structuring conventions (DSC).


 3.2 Objects

     PDF supports eight basic types of objects:

     • Boolean values
     • Integer and real numbers
     • Strings
     • Names
     • Arrays
     • Dictionaries
     • Streams
     • The null object
     Objects may be labeled so that they can be referred to by other objects. A labeled
     object is called an indirect object.

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