Here the abstract inlines are broken down until only true and usable tags will remain. Let's recall:
<!entity % inline " (#pcdata | f| x| %emph; |sq| %xref | %index | file )* " >
<!entity % emph " em|it|bf|sf|sl|tt|cparam " >
The emphasizes are gathering the tags for emphasizing inline text.
The different types of emphasizes are:
em-> The Emphasize Tag
I hate to be redundant but I have to say:
The emphasize tag you place for emphasized text.
Normally it's mapped to italic letters.
So if you write
<em/a emphasized text/ it will be mapped to
a emphasized text.
it-> The Italic Tag
The italic tag you place for a cursive mapping. If you write
<it/a italic text/ it will be mapped to a italic text.
bf-> The Boldface Tag
The boldface tag you place for a bold mapping. If you write
<bf/a bold text/ it will be mapped to a bold text.
sf-> The Swissfont Tag
I know that Tom Gordon from GMD is telling that this is the
sans serif tag.
My interpretation of the sf is swissfont wich for me is more easy
This is mapping the inlined text to a font wich is out of the helvetica family.
<sf/a swissfont text/ will be mapped to
sl-> The Slanted Tag
I think I skip the explanation.
<sl/a slanted text/ will be
mapped to a slanted text.
tt-> The Terminaltype Tag
Text tagged with terminaltype will be placed inline, just like all the
other text within a paragraph. It will not be included into source
output if you are workink as described in section
Literate Programming, even if it's
looking like typed code.
<tt/a terminal typed text/ will be
a terminal typed text.
Normally this one could be viewed the same level like one of the emphasize tags, but the definition of the linuxdoc dtd is placing it same level like the emphasizes, and so I do.
shortquote tag is a inline quotation, not forming an own paragraph.
<sq/a short quote/ is mapped to "a short quote".
The formula tag allows us to note down a mathematical formula within the
normal text, not appearing in an own line. So the text
<f>x=y<sup>2</sup></f> will be displayed as
Mathematical Fomulas for
the tags valid within the formula.
The external tag is passing the tagged data directly through the parser, without modifying it. E.g. to LaTeX.