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<title>12.1.4 Writer Implementations
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12.1.4 Writer Implementations
Three implementations of the writer object interface are provided as
examples by this module. Most applications will need to derive new
writer classes from the
<tt class=
"class">NullWriter
</tt> class.
<dl><dt><table cellpadding=
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"0"><tr valign=
"baseline">
<td><nobr><b><span class=
"typelabel">class
</span> <tt id='l2h-
3824' xml:id='l2h-
3824'
class=
"class">NullWriter
</tt></b>(
</nobr></td>
<td><var></var>)
</td></tr></table></dt>
A writer which only provides the interface definition; no actions are
taken on any methods. This should be the base class for all writers
which do not need to inherit any implementation methods.
<dl><dt><table cellpadding=
"0" cellspacing=
"0"><tr valign=
"baseline">
<td><nobr><b><span class=
"typelabel">class
</span> <tt id='l2h-
3825' xml:id='l2h-
3825'
class=
"class">AbstractWriter
</tt></b>(
</nobr></td>
<td><var></var>)
</td></tr></table></dt>
A writer which can be used in debugging formatters, but not much
else. Each method simply announces itself by printing its name and
arguments on standard output.
<dl><dt><table cellpadding=
"0" cellspacing=
"0"><tr valign=
"baseline">
<td><nobr><b><span class=
"typelabel">class
</span> <tt id='l2h-
3826' xml:id='l2h-
3826'
class=
"class">DumbWriter
</tt></b>(
</nobr></td>
<td><var></var><big>[
</big><var>file
</var><big>[
</big><var>, maxcol
<code> =
72</code></var><big>]
</big><var></var><big>]
</big><var></var>)
</td></tr></table></dt>
Simple writer class which writes output on the file object passed in
as
<var>file
</var> or, if
<var>file
</var> is omitted, on standard output. The
output is simply word-wrapped to the number of columns specified by
<var>maxcol
</var>. This class is suitable for reflowing a sequence of
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<span class=
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