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<TD>

<P>Puts a double box&#151;a box drawn with two lines&#151;around the table.</P>

<TR>

<TD>

<P>allbox</P>

<TD>

<P>Puts each item in the table in a box.</P>

<TR>

<TD>

<P>tab(<I>x</I>)</P>

<TD>

<P>Changes the column separation character to x.</P>

<TR>

<TD>

<P>linesize(<I>n</I>)</P>

<TD>

<P>Sets the point size of lines under column heads or of lines that make up boxes to n points.</P>

<TR>

<TD>

<P>delim(<I>xy</I>)</P>

<TD>

<P>Uses x and y as eqn delimiters. (eqn is discussed in Chapter 24, &quot;Formatting Equations with eqn.&quot;)</P></TABLE>

<P>The center and expand options are straightforward and do exactly what you would expect.

<BR></P>

<P>By default, tables are left-justified. The center option centers your table with respect to the defined line length. The table might not always look centered. It depends on what indents are used before the table and after it. You can use .in with a 
positive or negative value to adjust the horizontal placement of the table. Remember, though, to reset the indent that comes after the table.

<BR></P>

<P>The reasons for using expand are less obvious. expand makes the width of your table equal to the defined line length. You might want to do this for a special effect. It also comes in handy if you're working with a custom macro package that has outdented 

headings with text indented an inch or more. expand enables you to take advantage of the unused left margin.

<BR></P>

<HR ALIGN=CENTER>

<NOTE>

<IMG SRC="note.gif" WIDTH = 35 HEIGHT = 35><B>NOTE:</B> Occasionally, you get an error message from tbl that reads table too wide. Processing doesn't stop, though. The table is printed. Chances are, though, that it will be too wide. tbl does not respect 
margins. You can often use this feature to your advantage, however.

<BR></NOTE>

<HR ALIGN=CENTER>

<P>tbl provides three global options that you you can use to draw boxes around tables. Figure 23.1 shows an example of each option.

<BR></P>

<P>

<BR><B><A HREF="23unx01.gif">Figure 23.1.  The </B><B><I>box</I></B><B> options.</A></B>

<BR></P>

<P>allbox is useful when you have many narrow columns (perhaps with numeric data). The lines make the table easier to read. In most other situations, the lines are distracting and unattractive.

<BR></P>

<P>The tab option enables you to specify a different character as the column separator. Many people do this routinely. Just be careful to choose a character that doesn't appear in your table.

<BR></P>

<P>There is a benefit to changing the tab character to a single character such as # or !. If your input line is long, you might exceed the wrap margin, and your input line will become two lines. If you then join the two lines, your tab turns into a space. 

If you change the space to a tab, the line might split again. This is annoying. It is also less likely to happen if you are using # or !. # and ! are single characters, not 4 to 8 characters like the tab.

<BR></P>

<P>The linesize option affects all the lines in your table. If you use it to draw a heavy box around the whole table, you must adjust the point size for internal lines.

<BR></P>

<P>If your table contains equations, you can set the eqn delimiters in a tbl global option. These delimiters must not appear elsewhere in the table, except as eqn delimiters. They also can't be the same as the tab character. (Refer to Chapter 24, 
&quot;Formatting Equations with eqn,&quot; for more information.) 

<BR></P>

<H3 ALIGN="CENTER">

<CENTER><A ID="I11" NAME="I11">

<FONT SIZE=4><B>Advanced </B><B><I>tbl</I></B><B> Formatting</B>

<BR></FONT></A></CENTER></H3>

<P>tbl gives you control over almost every aspect of table formatting, including column headings, horizontal and vertical spanning, text blocks, spacing options and lines, and changing format options.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I12" NAME="I12">

<FONT SIZE=3><B>Column Headings</B>

<BR></FONT></A></CENTER></H4>

<P>To make column headings stand out, underline them. tbl provides several styles to choose from.

<BR></P>

<TABLE BORDER>

<TR>

<TD>

<P>_</P>

<TD>

<P>Draws a continuous single underscore the width of the table. When it used with allbox, it draws a double underscore under the column headings. The code line containing _ must have no other entries.</P>

<TR>

<TD>

<P>=</P>

<TD>

<P>Draws a continuous double underscore the width of the table. The code line containing = must have no other entries.</P>

<TR>

<TD>

<P>_[TAB]_</P>

<TD>

<P>Two or more underscores separated by tabs. _[TAB]_ draws a single underscore the width of the contents of each column.</P>

<TR>

<TD>

<P>=[TAB]=</P>

<TD>

<P>Two or more equals signs separated by tabs. =[TAB]= draws a double underscore the width of the contents of each column.</P>

<TR>

<TD>

<P>\_[TAB]\_</P>

<TD>

<P>Backslash underscores separated by tabs. \_ draws a single underscore the width of each column. (Does not work with newer versions of tbl.)</P>

<TR>

<TD>

<P>\=[TAB]\=</P>

<TD>

<P>Backslash equals signs separated by tabs. \= draws a double underscore the width of each column. (Does not work with newer versions of tbl.)</P></TABLE>

<P>To specify column headings that will appear on every page of a multipage table, use the .TS H and .TH macros.

<BR></P>

<P>Use .TS H to start your table if you are going to specify a column heading. Then use .TH after the lines that constitute the heading. Be sure to include underscores and spaces if they are part of the heading.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I13" NAME="I13">

<FONT SIZE=3><B>Horizontal and Vertical Spanning</B>

<BR></FONT></A></CENTER></H4>

<P>tbl accommodates both horizontal and vertical spanning. Use horizontal spanning to center a column heading over more than one column, as in

<BR></P>

<PRE>c s s</PRE>

<P>Figure 23.2 illustrates horizontal spanning.

<BR></P>

<P>

<BR><B><A HREF="23unx02.gif">Figure 23.2.  A table with horizontal </B><B>spanning.</A></B>

<BR></P>

<P>You can code vertical spanning in the tbl format options or in the table data. Vertical spanning in the column headings is produced by using ^ in the format specifications. Vertical spanning in the table data is produced by using \^.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I14" NAME="I14">

<FONT SIZE=3><B>Text Blocks</B>

<BR></FONT></A></CENTER></H4>

<P>A text block is a block of text&#151;a paragraph&#151;used as a table entry. Figure 23.3 shows a table with text blocks.

<BR></P>

<P>

<BR><B><A HREF="23unx03.gif">Figure 23.3. A table with text blocks.</A></B>

<BR></P>

<P>The text block is coded as part of the table entry:

<BR></P>

<PRE>1990-1991[TAB]T{

.na

Writer. \f2Jurassic Park II\fP, \f2Daughter of the Firm\fP, \f2The

Cat in the Hat Spends a Year in Provence\fP. Took best-selling ideas

and capitalized on them. Raised my income 576% in just one year.

T}

.sp .5

1991-date[TAB]T{

.na

Law Student. Attending Harvard Law School; expect to receive degree

this year.

T}</PRE>

<P>Because tbl right-justifies text blocks, you might want to turn off adjustment inside the text blocks, as in the previous example. Use .na to do this.

<BR></P>

<P>The number of text blocks that can be used within a single table varies, depending on the tbl version. If you're using a recent version, don't worry about this. Even if you're using an old version, don't worry. tbl will complain loudly if you use too 
many text blocks. Your only remedy is to break the table into smaller tables.

<BR></P>

<HR ALIGN=CENTER>

<NOTE>

<IMG SRC="note.gif" WIDTH = 35 HEIGHT = 35><B>NOTE:</B> Text blocks affect vertical spacing. There's a little more space between text block rows than there is between ordinary rows. If you notice this in a table, you might have to make even your short 
columns into text blocks.

<BR></NOTE>

<HR ALIGN=CENTER>

<P>Text blocks complicate a table. The first time you use them, you're almost certain to leave out the beginning or ending T-brace or to use an opening brace instead of a closing one. If you do this, tbl assumes your unmatched T-brace is data and prints 
it, so the error is easy to find.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I15" NAME="I15">

<FONT SIZE=3><B>Spacing and Lines</B>

<BR></FONT></A></CENTER></H4>

<P>The default gap between columns is 3 ens. You can adjust this gap by putting a number between your format options, as in

<BR></P>

<PRE>cB 2 lB 2 lB 1 cB</PRE>

<P>You can even set the gap to 0.

<BR></P>

<P>You can use .sp to put more space between table rows. (Don't use macros; use the troff primitive.) Using .sp .25 before and after an underscore and with column headings usually improves the appearance of the table.

<BR></P>

<P>If you have some two-line column heads and some one-line column heads, the allbox global option looks really awful. Similarly, if you've spanned any column, allbox doesn't work correctly. You can insert vertical lines between columns by using the pipe 
character (|). You can even combine vertical lines with changes in the column gap.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I16" NAME="I16">

<FONT SIZE=3><B>Changing Format Options</B>

<BR></FONT></A></CENTER></H4>

<P>You can change format options in the middle of a table. You can't change the number of columns, but you can change anything else. Use spanning to change the apparent number of columns.

<BR></P>

<P>To change tbl format options, use the .T&amp; macro and insert a line (or several lines) of format options.

<BR></P>

<H4 ALIGN="CENTER">

<CENTER><A ID="I17" NAME="I17">

<FONT SIZE=3><B>A Fancy Table</B>

<BR></FONT></A></CENTER></H4>

<P>The following code illustrates the advanced formatting techniques described in the previous sections. It produces the table shown in Figure 23.4.

<BR></P>

<P>

<BR><B><A HREF="23unx04.gif">Figure 23.4. A fancy table.</A></B>

<BR></P>

<PRE>.TS

center;

c s s s

lB cB cB cB

l l l l.

\fb\s14Old Garden Roses\s0\fP

.sp .25

Type[TAB]Examples[TAB]Color[TAB]Date

.sp .25

\_[TAB]\_[TAB]\_[TAB]\_

.sp .25

Alba[TAB]Celestial[TAB]milky peach[TAB]before1848

\^[TAB]Felicite Parmentier[TAB]pale pink[TAB]before 1834

.sp .5

Bourbon[TAB]La Reine Victoria[TAB]rich pink[TAB]1872

\^[TAB]Louise Odier[TAB]deep pink[TAB]1851

\^[TAB]Souvenir de la Malmaison[TAB]soft pink[TAB]1843

.sp .5

.Centifolia[TAB]Fantin-Latour[TAB]rich pink[TAB]unknown

.sp .5

China[TAB]Mutabilis[TAB]warm pink[TAB]unknown

.sp .5

Damask[TAB]Celsiana[TAB]soft pink[TAB]before 1750

\^[TAB]Mme. Hardy[TAB]white[TAB]1832

.sp .5

Gallica[TAB]Cardinal de Richelieu[TAB]rosy violet[TAB]1840

\^[TAB]Rosa Mundi[TAB]striped crimson[TAB]before 1581

[TAB][TAB][TAB]\0\0and pale pink

.TE</PRE>

<H3 ALIGN="CENTER">

<CENTER><A ID="I18" NAME="I18">

<FONT SIZE=4><B>Troubleshooting</B>

<BR></FONT></A></CENTER></H3>

<P>When you use tbl, keep the following points in mind:

<BR></P>

<UL>

<LI>Don't use macros in tables. They don't get digested properly. It's tempting to put in a .P. You do it without thinking, but often a single .P can wreck your table. Don't try to embed lists in tables. At the very least, don't try it when you're on a 
tight deadline. Macros and tables don't mix.

<BR>

<BR></LI>

<LI>Don't mix your font changes. If you use B in a format option line to get bold text, don't use f2 for italics. However, escape sequences in your table data are fine. Likewise, don't use macros.

<BR>

<BR></LI>

<LI>If you can't get the a format option to work, indent with \0. \0 inserts a space the width of a numeral.

<BR>

<BR></LI>

<LI>A common source of error in tables is a space after a T-brace. For some reason, it really makes tables crazy. The space is invisible, too, so you don't see it.

<BR>

<BR></LI></UL>

<HR ALIGN=CENTER>

<NOTE>

<IMG SRC="imp.gif" WIDTH = 68 HEIGHT = 35><B>TIP: </B>Use the ex command :se list (from vi). list turns each tab into a Ctrl-I, which shows up as ^I in your file but is actually a single character. You can count them to see whether you've put in too many. 

list also puts the line end symbol ($) at the end of each line in the file. A space between T{ and $ is easy to see. To turn list off, use :se nolist.

<BR></NOTE>

<HR ALIGN=CENTER>

<UL>

<LI>If you specify a column width and the contents of that column are longer than the specified width, your width setting is ignored. Think of it as a minimum width, not a maximum.

<BR>

<BR></LI>

<LI>If you omit a T-brace, tbl gets confused about your columns and might, for example, put column 2 in column 1. This plays havoc with your column width. You might not even see column 2 if this happens. Don't worry; column 2 isn't lost. It simply printed 

somewhere out in the middle of the Atlantic Ocean. When you fix your table, it will come back and behave.

<BR>

<BR></LI></UL>

<H3 ALIGN="CENTER">

<CENTER><A ID="I19" NAME="I19">

<FONT SIZE=4><B>Summary</B>

<BR></FONT></A></CENTER></H3>

<P>tbl is one of the most used, yet least liked programs, offered by the UNIX system. It is well worth the effort to learn at least the rudiments of tbl, because you can use tables to your advantage in unexpected situations. You can also make friends and 
influence supervisors if you take the time to learn tbl thoroughly. A good tbl debugger is hard to find.

<BR></P>

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