path: root/Master/texmf-dist/doc/texsis/base/TXSruled.doc

%% file: TXSruled.doc - Ruled Tables - TeXsis version 2.18
%% @(#) $Id: TXSruled.doc,v 18.2 2000/05/17 00:19:46 myers Exp $  
%======================================================================*
% (C) copyright 1994, 1999 by Eric Myers and Frank E. Paige.
% This file is a part of TeXsis.  Distribution and/or modifications
% are allowed under the terms of the LaTeX Project Public License (LPPL).
% See the file COPYING or ftp://ftp.texsis.org/texsis/LPPL
%======================================================================*
\ifx\undefined\bs \texsis\input TXSdocM.doc\draft\fi

\noindent
While \cs{halign} in Plain \TeX\ is convenient for making simple
tables, it is still difficult to make tables with horizontal and
vertical rules.  Indeed, typesetting ruled tables in \TeX\ has often
been likened to programming a computer in assembler language.  Even
\TeXbook\ acknowledges that ``people who know how to make ruled tables
are generally known as \TeX\ Masters.''\reference{Masters}\relax
D.E.~Knuth, {\sl The \TeX book} (Addison Wesley, 1986), page 245
\endreference
The macros described below take a great deal of the difficulty out of
making ruled tables, so that anybody can become a
\TeX\ Master, or at least a master of ruled tables.
\index{ruled tables}\index{tables!ruled|see{ruled tables}}

\def\VT{\char'174}      % the vertical var character ``|'' is needed below

        The basic idea behind making a ruled table is similar to
\cs{halign}, and the syntax is the same as the Princeton table macros
known as |TABLES.TEX| by Ray Cowan\reference{Cowan} Ray F.~Cowan, {\sl
Making Tables with Macros} (unpublished)
\endreference\index{Cowan, Ray F.}
(although the \TeXsis\ macros are quite different internally and run
about 5 times faster).  You begin the table material with \cs{ruledtable}
and end it with \cs{endruledtable}.  The table material is a list of items
to appear in the rows and columns of the tables.  Just as with \cs{halign},
you can separate items in different columns with |&|\index{&@{\tt \&}}
and end a row with
\cs{cr}.  The |&| \idx{alignment character}\index{&@{\tt \&}}
separates columns without putting a
vertical rule between the columns, while \cs{cr} ends a line and puts a
thin horizontal rule under it.  To get a vertical rule between columns
replace the |&|\index{&@{\tt \&}}
 with a `{\tt\VT}' (the vertical line), and to end a line
without a horizontal rule under it replace the \cs{cr} with \cs{crnorule}.
One important thing to remember is to end the last line in the table
with \cs{endruledtable} instead of \cs{cr}.

\bigskip
\pagecheck{2cm}

   As a first example, here is a simple ruled table,
{\singlespaced
\bigskip\tenpoint
\ruledtable
Year      |    World Population \cr
8000 B.C. |   ~~~5000000        \crnorule
~~50 B.C. |   ~200000000        \crnorule
1650 A.D. |   ~500000000        \crnorule
1850 A.D. |   1000000000        \crnorule
1945 A.D. |   2300000000        \crnorule
1980 A.D. |   4400000000        
\endruledtable
\smallskip}
\pagecheck{2cm}\noindent 
and here are the instructions that created it,
\TeXexample
|smalltt\ruledtable
Year      |VT    World Population \cr
8000 B.C. |VT   ~~~5000000        \crnorule
~~50 B.C. |VT   ~200000000        \crnorule
1650 A.D. |VT   ~500000000        \crnorule
1850 A.D. |VT   1000000000        \crnorule
1945 A.D. |VT   2300000000        \crnorule
1980 A.D. |VT   4400000000        
\endruledtable
|endTeXexample
This example also appears in \TeXbook, on page~246, where it is typeset using
|\halign|.  Compare how the two are constructed
and see which way you think is easier.

   By default each item in the table is centered in its column.  Inside
a table the tie character ``|~|''\index{~@{\tt\char'176}} takes up the space
of exactly one digit (it is the same as saying
|\phantom{0}|),\index{phantom@{\tt\bs phantom\lb 0\rb}} and this has been
used to line up the digits of the entries in both columns.  It is also
possible to change the definition of the \cs{TableItem} macro so that each
entry in each column is left or right justified.  This is described a
little bit later.

   Something to note about this example table is that the outer
rules are thicker than the others.  You can also get a thick
vertical rule between columns by using ``{\tt\bs\VT}'' in place of
``{\tt\VT}'', and you can get a thick horizontal rule below a row by
replacing the \cs{cr} with \cs{crthick}.  The widths of thick and
thin rules are controlled by the dimensions \cs{thicksize} and
\cs{thinsize}.  If you don't want thick rules at all simply say
|\thicksize=\thinsize|, which makes the thick rules as thin
as the thin rules.

   Some synonyms:  \cs{CR} is the same as \cs{crthick}, \cs{nr} is the
same as \cs{crnorule}, and \cs{crrule} is the same as \cs{cr} (actually
it's the other way around).  \cs{tab} is the same as |&|\index{&@{\tt \&}}
--- it separates columns without a vertical rule.  \cs{vb} is the same as 
{\tt\VT}, it separates columns with a thin vertical bar, while
\cs{Vb} is the same as {\tt\bs\VT} and separates the columns with a
thick vertical bar.  You can also use \cs{dbl} to separate columns
with a double vertical rule.

   As in Plain \TeX\ you can use \cs{span} in place of
|&|\index{&@{\tt \&}} (or the other column separators) to join two
columns together into one, and you can use \cs{omit} as the very first
token in a column to tell it to omit the fancy column layout (the
centering or other spacing).
You can also use \cs{multispan} to \cs{span} and \cs{omit} several
columns, just as in an \cs{halign}.
The only difference is that the number of columns you tell it to
\cs{multispan} is the number of columns of the table it spans --- in a
ruled table constructed with \cs{halign} you would count the columns
{\sl and} any vertical rules (because the rules are also columns of
the \cs{halign}).



\table{example-II}
\caption{Another example of a ruled table.}
\intablelist{Example of a ruled table --- AT\&T Common Stock.}
\singlespaced
\tenpoint
\ruledtable
\multispan3\hfil AT\&T Common Stock \hfil\CR
 Year \dbl Price | Dividend \cr
 1971 \dbl 41-54 | \$2.60   \cr
 ~~~2 \dbl 41-54 | \$2.70   \cr
 ~~~3 \dbl 46-55 | \$2.87   \cr
 ~~~4 \dbl 40-53 | \$3.24   \cr
 ~~~5 \dbl 45-52 | \$3.40   \cr
 ~~~6 \dbl 51-59 |  ~~.95
\endruledtable
\endtable

  \Tbl{example-II} is another sample table, again taken
{from} \TeXbook.  Something important to notice is that the last
ruled table example didn't have a table number or a caption,
while this one does.  That's because the last example was created
using just \cs{ruledtable}, while this example is inside of
\cs{table}.  The point is that \cs{table} and \cs{ruledtable} do
separate things and can be used either separately or together;
\cs{table} creates the space for the table and gives it a caption
and a number, while \cs{ruledtable} actually constructs the body of
the ruled table.  The instructions that created \Tbl{example-II}
are:
\smallskip\goodbreak
\TeXexample
|smalltt\table{example-II}
\caption{Another example of a ruled table.}
\singlespaced
\ruledtable
\multispan3\hfil AT\&T Common Stock \hfil\CR
Year \dbl Price |VT Dividend \cr
1971 \dbl 41-54 |VT \$2.60   \cr
~~~2 \dbl 41-54 |VT \$2.70   \cr
~~~3 \dbl 46-55 |VT \$2.87   \cr
~~~4 \dbl 40-53 |VT \$3.24   \cr
~~~5 \dbl 45-52 |VT \$3.40   \cr
~~~6 \dbl 51-59 |VT  ~~.95
\endruledtable
\endtable
|endTeXexample
\bigskip\goodbreak

\table{SiHCl}
\caption{Parameters used in the MS-X$\alpha$ calculations for 
        the chlorosilane molecules, H$_{\rm x}$SiCl$_{\rm 4-x}$; 
        x=0--4.}
\intablelist{Example of a ruled table --- Parameters used in the
        MS-X$\alpha$ calculations for the chlorosilane molecules, 
        H$_{\rm x}$SiCl$_{\rm 4-x}$; x=0--4.}
\singlespaced
\tenpoint
\ruledtable
\vctr{Molecule} | \vctr{Region} | Radius | 
  \vctr{$\alpha _{\rm HF}$}|\multispan{2} $l_{\rm max}$ \crnorule
\cskip | \cskip | \cskip |\cskip|    \crule     |  \crule \crpart 
       |        | (au)   |      | initial state | final state \CR

SiCl$_4$      | outersphere | 6.21 | 0.7238 | 4 | 7\crnorule
              | Si          | 2.20 | 0.7275 | 2 | 3\crnorule
              | Cl          | 2.40 | 0.7233 | 2 | 3\cr

SiHCl$_3$     | outersphere | 6.21 | 0.7260 | 4 | 7\crnorule
              | Si          | 2.16 | 0.7275 | 2 | 3\crnorule
              | Cl          | 2.40 | 0.7233 | 2 | 3\crnorule
              | H           | 1.20 | 0.7772 | 1 | 2\cr

SiH$_2$Cl$_2$ | outersphere | 6.25 | 0.7295 | 4 | 7\crnorule
              | Si          | 2.20 | 0.7275 | 2 | 3\crnorule
              | Cl          | 2.40 | 0.7233 | 2 | 3\crnorule
              | H           | 1.20 | 0.7772 | 1 | 2\cr

SiH$_3$Cl     | outersphere | 6.30 | 0.7360 | 4 | 7\crnorule
              | Si          | 2.20 | 0.7275 | 2 | 3\crnorule
              | Cl          | 2.40 | 0.7233 | 2 | 3\cr

SiH$_4$       | outersphere | 4.10 | 0.7524 | 4 | 7 \crnorule
              | Si          | 2.04 | 0.7275 | 2 | 3 \crnorule
              | H           | 1.20 | 0.7772 | 1 | 2 
\endruledtable
\bigskip\bigskip
\endtable

Sometimes it is desirable to have rules across only some of the columns
of a table.  In this case put \cs{crule} in the columns that are to have
rules, \cs{cskip} in the columns where no rules are desired, and
end the line with \cs{crpart}, which signals that the line contains a
partial rule.  The column headings in  \Tbl{SiHCl} are an example of
partial rules in a table.
That table was created with the commands,\reference{Bozek, 1991}
J.D.~Bozek, Ph.D. thesis (unpublished), Department of Chemistry,
University of Western Ontario, London, Ontario CANADA
\endreference\relax
\TeXexample
|smalltt\table{SiHCl}
\caption{...}
\singlespaced\tenpoint
\ruledtable
\vctr{Molecule} |VT \vctr{Region} |VT Radius |VT 
  \vctr{$\alpha _{\rm HF}$}|VT\multispan{2} $l_{\rm max}$ 
\crnorule
\cskip |VT \cskip |VT \cskip |VT\cskip|VT    \crule     |VT  \crule \crpart 
       |VT        |VT (au)   |VT      |VT initial state |VT final state \CR
SiCl$_4$      |VT outersphere |VT 6.21 |VT 0.7238 |VT 4 |VT 7 \crnorule
              |VT Si          |VT 2.20 |VT 0.7275 |VT 2 |VT 3 \crnorule
              |VT Cl          |VT 2.40 |VT 0.7233 |VT 2 |VT 3 ...
...
\endruledtable
\endtable
|endTeXexample
\bigskip\goodbreak


   Ruled tables are normally centered on the page, but you can turn
off the centering with \cs{noncenteredtables}.
Then the table becomes just another piece to add to a horizontal list.
One thing this lets you do is have two tables side by side on the
page, like so:
\nobreak
\noncenteredtables\index{ruled tables!centered}
\bigskip
\line{\tenpoint\ruledtable
Item ABC | Item DEF \cr
Item GHI | Item JKL \endruledtable
\hfil
\ruledtable
Data 111 | Data 222 \cr
Data 333 | Data 444 \cr
Data 555 | Data 666 \endruledtable}
\bigskip
\pagecheck{5\baselineskip}
\noindent 
This pair of tables was produced by saying:
\TeXexample
|smalltt\noncenteredtables
\medskip
\line{\ruledtable
Item ABC |VT Item DEF \cr
Item GHI |VT Item JKL \endruledtable
\hfil
\ruledtable
Data 111 |VT Data 222 \cr
Data 333 |VT Data 444 \cr
Data 555 |VT Data 666 \endruledtable}
\smallskip
|endTeXexample
\noindent Saying \cs{centeredtables} turns table centering back on.
Tables are then centered across the page, and a table is then 
added to a {\sl vertical\/} list.
\bigskip\goodbreak

        Usually \cs{ruledtable} makes tables as wide as their natural
width, but it is possible to make them wider by setting the dimension
\cs{tablewidth} to the width desired before saying \cs{ruledtable}.  We can
make the same table in \Tbl{example-II} but with the width set to
10cm: \index{ruled tables!size}
\bigskip
\noncenteredtables
\tablewidth=10cm
\line{\tenpoint\hfil\vbox{\singlespaced
  \ruledtable
  \multispan3\hfill AT\&T Common Stock \hfill\CR
  Year \dbl Price | Dividend \cr
  1971 \dbl 41-54 | \$2.60   \cr
  ~~~2 \dbl 41-54 | \$2.70   \cr
  ~~~3 \dbl 46-55 | \$2.87   \cr
  ~~~4 \dbl 40-53 | \$3.24   \cr
  ~~~5 \dbl 45-52 | \$3.40   \cr
  ~~~6 \dbl 51-59 |  ~~.95\rlap* 
  \endruledtable
  \hbox{* (first quarter only)}
\vss}\hfil}
\smallskip
\noindent  
The careful reader will notice that the version of
\Tbl{example-II} in \TeXbook\ had a footnote to the last entry,
and we have added that here.  To do so we had to put the footnote in an
\cs{hbox} and stack it under the table, so we had to turn off table
centering.  The table is therefore a bit more complicated to make, but
not much: \index{ruled tables!footnotes}
\TeXexample
|smalltt\noncenteredtables
\tablewidth=10cm
\line{\tenpoint\hfil\vbox{\singlespaced
  \ruledtable
  \multispan3\hfill AT\&T Common Stock \hfill\CR
  Year \dbl Price |VT Dividend \cr
  1971 \dbl 41-54 |VT \$2.60   \cr
  ~~~2 \dbl 41-54 |VT \$2.70   \cr
  ~~~3 \dbl 46-55 |VT \$2.87   \cr
  ~~~4 \dbl 40-53 |VT \$3.24   \cr
  ~~~5 \dbl 45-52 |VT \$3.40   \cr
  ~~~6 \dbl 51-59 |VT  ~~.95\rlap* 
  \endruledtable
  \hbox{* (first quarter only)}
\vss}\hfil}
|endTeXexample
\centeredtables         % turn back on!
\noindent
If we had not wanted to add the footnote, then the table would have
been typed the same way as \Tbl{example-II} except for setting
the \cs{tablewidth}.

        Important note:  \cs{tablewidth} is turned ``off'' after the
table is made, so  the next table will have its natural width unless
you explicitly set \cs{tablewidth} again! \index{ruled tables!size}
\bigskip\goodbreak

        \cs{ruledtable} normally inserts a \cs{quad} of space around each
item. If you have a very wide table, especially one with many columns,
you may wish to reduce this.  \cs{TightTables} make this spacing a single
space, the minimum acceptable.  \cs{LooseTables} restores the default
spacing.  You can define this space to be something else by
re-defining \cs{tablespace}, for example as \index{ruled tables!spacing}
\TeXexample
\def\tablespace{\ \ }
|endTeXexample
\noindent 
If the table is still too wide with \cs{TightTables}, you will probably
have to reformat it or print it in landscape mode (tilted 90\degrees on
the page).
\bigskip\goodbreak


        The careful reader may also have noticed that in the
examples in \Tbl{example-II} and \Tbl{SiHCl}  we said
\cs{singlespaced}.  That's
because the spacing of the rows of a table can be controlled just like
the spacing of the text with \cs{singlespaced}, \cs{doublespaced},
etc. \index{ruled tables!spacing}
The space between the rows of a table is set by a strut called
\cs{tstrut}, which holds the rows apart.  Its default definition is
\TeXexample
\def\tstrut{\vrule height 3.1ex depth 1.2ex width 0pt}
|endTeXexample
\noindent
You can change the spacing between rows by changing the definition of
this strut.  One of the things \cs{singlespaced}  does is define the
\cs{tstrut} to be 0.5ex higher and deeper than a parenthesis.
\cs{doublespaced}, \cs{triplespaced}, and \cs{widenspacing} all increase the
height and depth of the strut in proportion to the increase in the
baseline spacing.

        If you put something in a table which is larger than the strut,
then it will touch the rules above or below.  You can fix this by
inserting your own strut into that row.  More simply, you can say
\cs{bigitem}\arg{stuff}, and the ``stuff'' will be positioned correctly
with a nice amount of space above and below. \index{ruled tables!spacing}
\medskip

        You can also decide whether or not you want diagnostic messages
printed when a table is created.  Saying \cs{tableinfotrue} causes a
message to be printed on your terminal every time a ruled table is
created.  The message tells you how many rows and columns were in the
table.  This is useful information, because it can tell you immediately
if you made a mistake in the table or left out a row or column.
\cs{tableinfotrue} is the default, but you can turn off these messages
by saying
\cs{tableinfofalse}. In any case, you will be warned if a row has a
different number of columns from the previous one.
\medskip

        The tables we have demonstrated so far all contain numbers, but
sometimes it is desirable to have an entry in a table which is a
paragraph of text.  \index{ruled tables!text} For that purpose, you can
use \cs{para}\arg{text}.  The width of the paragraph is determined by
the dimension \cs{parasize}, which defaults to 4 inches.
\medskip

Tables \use{Tb.tablemac;a} and \use{Tb.tablemac;b} summarize the most
important commands for making ruled tables.

  Finally, we can discuss how you can change how each column of
a table is constructed.  The macros which build the table take
each entry and pass it to a macro called \cs{TableItem}.  The
default definition of \cs{TableItem} is:
\vskip 0pt\goodbreak
\TeXexample
|smalltt\def\TableItem#1{%              % centers item in ruled table
   \hfil\tablespace             % left glue
   #1\killspace                 % item, no space after
   \tablespace\hfil             % right glue
    }%
|endTeXexample


%% TABLE A

\bottomtable{tablemac;a}
\caption{Basic table macros for use with {\tt\bs ruledtable}.}%
\intablelist{Basic macros for {\tt\bs ruledtable}}%
\tablewidth=\hsize
\LeftJustifyTables
\ruledtable
\sl Macro name\relax         
        | \sl Description \relax \crthick
\tt\bs ruledtable\relax      
        | \para{Starts a ruled table.}\cr
\vtop{\noindent\hsize=1.6in\normalbaselines
  \tt\char124\quad \rm (vertical bar)\hfil\break
  or \tt\bs vb\hfil}\relax
        | \para{Separates one column from the next, with a
        a thin vertical rule between them.}\cr
\tt\&\ \rm or\tt\ \bs tab \relax
        | \para{Separates one column from the next, but with
        no rule between them.}\cr
\tt\bs cr\relax              
        | \para{Ends the current row, and starts the next
        one.  The completed row will be separated from
        the next with a thin horizontal rule.}\cr
\vtop{\noindent\hsize=1.6in\normalbaselines
\tt\bs crthick \hfil\break \rm or \tt\bs CR\hfil }\relax         
        | \para{Similar to {\tt\bs cr}, but the rows will
        be separated with a thick horizontal rule.}\cr
\vtop{\noindent\hsize=1.6in\normalbaselines
\tt\bs crnorule \hfil\break \rm or \tt\bs nr\hfil }\relax         
        | \para{Similar to {\tt\bs cr}, but the rows will
        not be separated by a rule.}\cr
\tt\bs\char124 \relax        
        | \para{Same as {\tt\char124}, but with a thick vertical rule.}\cr
\tt\bs dbl
        | \para{Same as {\tt\char124}, but with two thin vertical rules.}\cr
\tt\bs endruledtable\relax        
        | \para{Ends the ruled table.}%
\endruledtable
\line{\hfil {\sl Continued...}}%
\endtable

%% TABLE B (FULL PAGE)

\fulltable{tablemac;b}
\caption{Additional macros for use with {\tt\bs ruledtable}.}
\intablelist{Additional macros for {\tt\bs ruledtable}}
\tablewidth=\hsize
\LeftJustifyTables
\line{{\sl Continued...}\hfil}
\smallskip
\ruledtable
\sl Macro name\relax         
        | \sl Description \relax \crthick
\tt\bs multispan\lb{\it n}\rb\relax 
        | \para{Makes the next entry span the next $n$
        columns, where $n$ is an integer, $n>0$.
        See {\tt\bs omit} below.} \cr
\tt\bs omit \relax           
        | \para{This \TeX\ primitive causes the normal
        template for its entry to be omitted, allowing
        the user to do something else with this entry.} \cr
\tt\bs para\arg{text}\relax
        | \para{Formats {\sl text\/} into a neat little
        paragraph like this one.  The width of the
        paragraph produced is determined by the dimension 
        {\tt\bs parasize}.  The default is 4 inches.  } \cr
\tt\bs parasize=\meta{dimen} \relax
        | \para{Sets the width of paragraphs for the {\tt\bs para} 
        macro.} \cr
\tt\bs TableItem\arg{stuff}\relax     
        | \para{Used in the standard template, this
        macro centers its argument in the column.  The
        user can redefine it for special effects.} \cr
\tt\bs tablespace
        | \para{The spacing around each item for {\tt\bs TableItem}.}\cr
\vtop{\noindent\hsize=1.4in\normalbaselines
\tt\bs LooseTables \hfil\break
\tt\bs TightTables\hfil}\relax
        | \para{Set {\tt\bs tablespace} to {\tt\bs quad} and {\tt\bs\ } 
        respectively.\hfill\break\ }\cr
\vtop{\noindent\hsize=1.6in\normalbaselines
\tt\bs TrailingSpaces \hfil\break
\tt\bs NoTrailingSpaces \hfil}\relax
        | \para{Use trailing spaces and glue items in table entries
        (default) or ignore them. See text.}\cr
\tt\bs bigitem\arg{stuff}\relax     
        | \para{Use this for something that would normally
        not fit in one line of a table to make the spacing
        between rows large enough for this item.} \cr
\tt\bs vctr\arg{stuff}\relax     
        | \para{Centers the item {\sl vertically\/} so that
        it can appear between two rows.}\cr
\tt\bs centeredtables\relax  
        | \para{Turns table centering on.  Each table
        will be centered left-to-right on the page.
        This is the default.} \cr
\tt\bs noncenteredtables\relax
        | \para{Turns table centering off.  Each table
        is returned as an {\tt\bs hbox}, and it is up
        to the user to place it as desired.} \cr
\vtop{\noindent\hsize=1.6in\normalbaselines
\tt\bs tableinfotrue \hfil\break
\tt\bs tableinfofalse\hfil}\relax
        | \para{Turns on or off the diagnostic message telling
        you how many rows and columns were found in the
        table. }\cr
\tt\bs thicksize=\meta{dimen} \relax
        | \para{This dimension specifies the thickness
        of the thick rules in the table.  The default
        size is 1.5 points.} \cr
\tt\bs thinsize=\meta{dimen} \relax
        | \para{This dimension specifies the thickness
        of thin rules in the table.  The default
        size is 0.8 points.} \cr
\tt\bs tablewidth=\meta{dimen} \relax
        | \para{Specifies how wide to make the next
        table.  If not specified, the table is made to
        its natural width.  This value is reset
        following the construction of each table.} 
\endruledtable
\vfill
\endtable


The \cs{hfil} glue on both sides of the argument causes the item to be
centered in the column, while \cs{tablespace} (which defaults to \cs{quad})
insures that there will be at least some amount of space between the
item and the vertical rules on each side. Because of the way that
\TeX\ handles macro arguments, if you type a table with spaces between
the text and the next column separator, an extra \cs{space} will be
inserted into the table. If you first say \cs{NoTrailingSpaces}, then
\cs{killspace} in the above macro is defined to remove any trailing glue
items. \cs{hfill} is redefined by the table macros so that if it is the
last token in an entry, then that entry is properly left justified,
but to insert any other trailing glue, you must say
\example
\meta{text}\meta{glue}|\null|
\endexample
\noindent
The default is \cs{TrailingSpaces}, which does incorporate any trailing
spaces into the table but which also treats any trailing glue items
normally. 


        You can change the definition of \cs{TableItem} to suit your own
purpose.  The simplest modification is to omit the \cs{hfil} on the left
or right so that each entry is right or left justified.  This is so
commonly used that saying \cs{RightJustifyTables} or
\cs{LeftJustifyTables} makes the appropriate change for you.  Saying
\cs{NoJustifyTables} restores \cs{TableItem} to its original centering
function. \index{ruled tables!customization}

  Since \cs{TableItem} is used to create every column of the table, you
cannot use it to modify a single column.  To justify just one column
you can simply put \cs{hfill} to the left or right of each item in the
column, since \cs{hfill} is infinitely more stretchy than \cs{hfil}. (The
behavior of glue items other than \cs{hfill} depends on whether
\cs{NoTrailingSpaces} has been set.)  With a little more work it is
possible to design special or unusual tables by redefining the
``preamble'' of the table.  This is possible because \cs{ruledtable}
uses \cs{halign} with a preamble called \cs{TablePreamble}.  The default
definition of \cs{TablePreamble} is:
\TeXexample
\def\TablePreamble{%                    % \ruledtable preamble
   \TableItem{####}%                    % the first item
   \plaintab\plaintab                   % && means repeat this
   \TableItem{####}%                    % the subsequent items
   \plaincr}%                           % end of preamble
|endTeXexample
\noindent
The syntax for \cs{TablePreamble} is like an \cs{halign} preamble in Plain
\TeX\, but with |&| replaced by \cs{plaintab}, \cs{cr} replaced by
\cs{plaincr}, and |#| replaced by |####|.  If you have read this far and
want to try changing \cs{TablePreable} then you should read the source
code and the comments that go with it in the file |TXSruled.tex.|

As a final note we point out that it is also possible for you to create
your own column separators with the macro \cs{nextcolumn}.  This macro
takes a single argument which is used to separate one column of the
table from another. Thus for example, the \cs{dbl} macro for creating a
double vertical rule between columns is defined as:
\TeXexample
\def\dbl{%                               
   \nextcolumn{\vrule width\thinsize     
   \hskip\thinsize\vrule width\thinsize}}
|endTeXexample
\relax
\index{ruled tables!customization}

%>>> EOF TXSruled.doc <<<