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<p>

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<a name="TYPESETTING">
	<h1 align="center"><u>USING TYPESETTING MACROS DURING DOCUMENT PROCESSING</u></h1>
</a>

During document processing, most of the
<a href="typesetting.html#MACROS_TYPESETTING">typesetting macros</a>
affect type in the document globally.  For example, if you turn kerning
off, pairwise kerning is disabled not only in paragraphs, but
also in headers, footers, quotes, and so on.
<p>
Typesetting macros that alter margins and line lengths affect
<a href="definitions.html#TERMS_RUNNING">running text</a>
globally (or at least try to), but leave headers/footers and footnotes
alone.  (To indent footnotes, see the full explanation of the
<a href="docelement.html#FOOTNOTE">FOOTNOTE</a>
macro.)
<p>
<strong>Mom</strong>'s tabs
(both
<a href="typesetting.html#TYPESETTING_TABS">typesetting tabs</a>
and
<a href="typesetting.html#STRING_TABS">string tabs</a>)
behave as expected in running text during document processing.  Tab
structures that do not exceed the line length of running text are
preserved sensibly from page to page, and, if
<a href="docprocessing.html#COLUMNS">COLUMNS</a>
are enabled, from column to column.
<p>
Some typesetting macros, however, when used during document
processing, behave in special ways.  These are the macros that deal
with the basic parameters of type style: horizontal and vertical
margins, line length,
<a href="definitions.html#TERMS_FAMILY">family</a>,
<a href="definitions.html#TERMS_FONT">font</a>,
<a href="definitions.html#TERMS_PS">point size</a>,
<a href="definitions.html#TERMS_LEADING">leading</a>,
and
<a href="definitions.html#TERMS_QUAD">quad</a>.

<p>
<strong>Mom</strong> assumes that any changes to these parameters
stem from a temporary need to set type in a style different from that
provided by <strong>mom</strong>'s
<a href="docelement.html#INDEX_DOCELEMENT">document element tags</a>.
In other words, you need to do a bit of creative typesetting in the
middle of a document.
<p>
The following lists those typesetting macros whose behaviour during
document processing requires some explanation.
(Please refer to
<a href="#TB_MARGINS">Top and bottom margins in document processing</a>
for information on how <strong>mom</strong> interprets
<a href="typesetting.html#T_MARGIN">T_MARGIN</a>
and
<a href="typesetting.html#B_MARGIN">B_MARGIN</a>
in document processing.  Additionally, see
<a href="#ADD_SPACE">ADD_SPACE</a>
if you encounter the problem of trying to get <strong>mom</strong>
to put space at the tops of pages after the first.)

<pre>
MACRO           EFFECT DURING DOCUMENT PROCESSING
-----           ---------------------------------

L_MARGIN        *The left margin of all running text
                 assumes the new value.

                *The line length remains unaltered.

                *The header and footer left margin
                 remain at the current document default.

                (You won't use this often by itself.  Most
                 likely, you'll use it in combination with
                 R_MARGIN or LL.)

R_MARGIN        *The right margin of all running text
                 assumes the new value.  In other words,
                 the line length is altered.

                *The header and footer right margin
                 remain at the current document default.

LL              *The line length of all running text
                 is set to the new value.

                *The header and footer line length remain
                 at the current document default.

FAMILY          *Changes family for the duration of the
                 current tag only.  As soon as another document
                 element tag is invoked, the family reverts to
                 the current default for the new tag.

FT              *Changes font for the duration of the
                 current tag only.  As soon as another document
                 element tag is entered, the font reverts
                 to the current default for the new tag.

                 N.B. -- \*[SLANT] and \*[BOLDER] affect
                 paragraph text, and remain in effect for all
                 paragraphs until turned off.  If you want to
                 use them in a macro that takes a string
                 argument, include the escape in the string.
                 \*[COND] and \*[EXT] behave similarly.

PT_SIZE         *Changes point size for the duration of the
                 current tag only.  As soon as another document
                 element tag is entered, the point size reverts
                 to the current document default for the new
                 tag.

LS              *Changes line space for the duration of the
                 current tag only.  As soon as another document
                 element tag is entered, the line space reverts to
                 the current document default for the new
                 tag.

                 Using LS to temporarily change leading within a
                 document will almost certainly result in a bottom
                 margin that doesn't align with the bottom margin
                 of subsequent pages.  You'll need to use the SHIM
                 macro to get mom back on track when you're ready
                 to return to the document's default leading.

QUAD            *Changes quad for the duration of the
                 current tag only.  As soon as another document
                 element tag is entered, the quad reverts to
                 the current document default for the new
                 tag.

                 N.B. -- Line-for-line quadding macros
                 (LEFT, CENTER, RIGHT) are also temporary,
                 overridden by the QUAD value of any subsequent
                 document element tag.
</pre>
<hr>

<!=====================================================================>

<a name="TB_MARGINS">
	<h2><u>Top and bottom margins in document processing</u></h2>
</a>

Normally, <strong>mom</strong> establishes the top and bottom margins
of
<a href="definitions.html#TERMS_RUNNING">running text</a>
in documents from the values of <strong>HEADER_MARGIN +
HEADER_GAP</strong> and <strong>FOOTER_MARGIN + FOOTER_GAP</strong>
respectively.  However, if you invoke
<a href="typesetting.html#T_MARGIN">T_MARGIN</a>
or
<a href="typesetting.html#B_MARGIN">B_MARGIN</a>
either before or after
<a href="docelement.html#START">START</a>,
they set the top and bottom margins of running text irrespective
of <strong>HEADER_GAP</strong> and <strong>FOOTER_GAP</strong>.
<p>
Put another way, in document processing, <strong>T_MARGIN</strong>
and <strong>B_MARGIN</strong> set the top and bottom margins of
running text, but have no effect on the placement of
<a href="definitions.html#TERMS_HEADER">headers</a>,
<a href="definitions.html#TERMS_FOOTER">footers</a>,
or page numbers.

<a name="ADD_SPACE">
	<h2><u>ADD_SPACE</u></h2>
</a>

<p>
Occasionally, you may want to insert space before the start of
<a href="definitions.html#TERMS_RUNNING">running text</a>
on pages after the first.
<p>
You might have tried using
<a href="typesetting.html#ALD">ALD</a>
or
<a href="typesetting.html#SPACE">SPACE</a>
and found it did nothing.  This is because <strong>mom</strong>
normally inhibits any extra space before the start of running text
on pages after the first.
<p>
If you need the space, you must use the macro,
<strong>ADD_SPACE</strong>, in conjuction with
<a href="typesetting.html#NEWPAGE">NEWPAGE</a>.
<strong>ADD_SPACE</strong> takes as its single argument the
distance you want <strong>mom</strong> to advance from the normal
baseline position at the top of the page.  A
<a href="definitions.html#TERMS_UNITOFMEASURE">unit of measure</a>
is required.

<p>
For example, say you wanted to insert 2 inches of space before the
start of running text on a page other than the first.  You'd
accomplish it with

<p>
<pre>
	.NEWPAGE
	.ADD_SPACE 2i
</pre>

which would terminate your current page, break to a new page,
print the header (assuming headers are on) and insert 2 inches of
space before the start of running text.
<p>
Since adding space in this way is almost sure to disrupt
<strong>mom</strong>'s ability to guarantee perfectly flush bottom
margins, I highly recommend using the
<a href="docprocessing.html#SHIM">SHIM</a>
macro immediately after <strong>ADD_SPACE</strong>.
<p>
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