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ShowTable(3)





NAME

       ShowTable - routines to display tabular data in several formats.


USAGE

       "use Data::ShowTable;"

       ShowTable { parameter => value, ... };

       ShowTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub ];

       ShowDatabases \@dbnames;

       ShowDatabases { parameter => value, ... };

       ShowTables \@tblnames;

       ShowTables { parameter => value, ... };

       ShowColumns \@columns, \@col_types, \@col_lengths, \@col_attrs;

       ShowColumns { parameter => value, ... };

       ShowBoxTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub ];

       ShowBoxTable { parameter => value, ... };

       ShowSimpleTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub];

       ShowSimpleTable { parameter => value, ... };

       ShowHTMLTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub];

       ShowHTMLTable { parameter => value, ... };

       ShowListTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub];

       ShowListTable { parameter => value, ... };

       "package Data::ShowTable";

       $Show_Mode = 'mode';

       $Max_Table_Width = number;

       $Max_List_Width = number;

       $No_Escape = flag;

       %URL_Keys = { "$colname" => "$col_URL", ... };

       @Title_Formats = ( fmt1_html, <fmt2_html>, ... );

       @Data_Formats = ( fmt1_html, <fmt2_html>, ... );

       ShowRow $rewindflag, \$index, $col_array_1 [, $col_array_2, ...;]

       $fmt = ShowTableValue $value, $type, $max_width, $width, $precision,
       $showmode;

       [$plaintext = ] PlainText [$htmltext];


DESCRIPTION

       The ShowTable module provides subroutines to display tabular data, typ-
       ially from a database, in nicely formatted columns, in several formats.
       Its arguments can either be given in a fixed order, or, as a single,
       anonymous hash-array.

       The output format for any one invocation can be one of four possible
       styles:

       Box       A tabular format, with the column titles and the entire table
                 surrounded by a "box" of ""+"", ""-"", and ""|"" characters.
                 See "ShowBoxTable" for details.

       Table     A simple tabular format, with columns automatically aligned,
                 with column titles.  See "ShowSimpleTable".

       List      A list style, where columns of data are listed as a
                 name:value pair, one pair per line, with rows being one or
                 more column values, separated by an empty line.  See
                 "ShowListTable".

       HTML      The data is output as an HTML TABLE, suitable for display
                 through a Web-client.  See "ShowHTMLTable".  Input can either
                 be plain ASCII text, or text with embedded HTML elements,
                 depending upon an argument or global parameter.

       The subroutines which perform these displays are listed below.


EXPORTED NAMES

       This module exports the following subroutines:

        ShowDatabases    - show list of databases
        ShowTables       - show list of tables
        ShowColumns      - show table of column info
        ShowTable        - show a table of data
        ShowRow          - show a row from one or more columns
        ShowTableValue   - show a single column's value
        ShowBoxTable     - show a table of data in a box
        ShowListTable    - show a table of data in a list
        ShowSimpleTable  - show a table of data in a simple table
        ShowHTMLTable    - show a table of data using HTML
        PlainText        - convert HTML text into plain text

       All of these subroutines, and others, are described in detail in the
       following sections.


MODULES


ShowTable

       Format and display the contents of one or more rows of data.

        ShowTable { parameter => value, ... };

        ShowTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub [,
       $max_width ] [, $show_mode ] ];

       The ShowTable subroutine displays tabular data aligned in columns, with
       headers.  ShowTable supports four modes of display: Box, Table, List,
       and HTML.  Each mode is described separately below.

       The arguments to ShowTable may be given in one of two ways: as a
       hashed-array, or by a combination of fixed order arguments, and some
       package-global variable settings.  The hash-array parameters correspond
       to the fixed arguments and the global-parameter settings.

       In the list below, both the hash-array parameter name and the fixed-
       order argument name is given as the value.  In the case where there is
       no fixed-order argument for a given parameter-value pair, then the cor-
       responding global variable name is given.

       "titles" => \@titles
                 A reference to an array of column names, or titles.  If a
                 particular column name is null, then the string "Field_num"
                 is used by default.  To have a column have no title, use the
                 empty string.

       "types" => \@types
                 A reference to an array of types, one for each column.  These
                 types are passed to the fmt_sub for appropriate formatting.
                 Also, if a column type matches the regexp
                 ""/text|char|string/i"", then the column alignment will be
                 left-justified, otherwise it will be right-justified.

       "widths" => \@widths
                 A reference to an array of column widths, which may be given
                 as an integer, or as a string of the form: "width.precision".

       "row_sub" => \&row_sub
                 A reference to a subroutine which successively returns rows
                 of values in an array.  It is called for two purposes, each
                 described separately:

                 * To fetch successive rows of data:

                     @row = &$row_sub(0);

                 When given a null, zero, or empty argument, the next row is
                 returned.

                 * To initialize or rewind the data traversal.

                     $rewindable = &$row_sub(1);

                 When invoked with a non-null argument, the subroutine should
                 rewind its row pointer to start at the first row of data.  If
                 the data which row_sub is traversing is not rewindable, it
                 must return zero or null.  If the data is rewindable, a
                 non-null, non-zero value should be returned.

                 The row_sub must expect to be invoked once with a non-null
                 argument, in order to discover whether or not the data is
                 rewindable.  If the data cannot be rewound, row_sub will
                 thereafter only be called with a zero argument.

                 Specifically, row_sub subroutine is used in this manner:

                     $rewindable = &$row_sub(1);
                     if ($rewindable) {
                         while ((@row = &$row_sub(0)), $#row >= 0) {
                             # examine lengths for optimal formatting
                         }
                         &$row_sub(1);   # rewind
                     }
                     while ((@row = &$row_sub(0)), $#row >= 0) {
                         # format the data
                     }

                 The consequence of data that is not rewindable, a reasonably
                 nice table will still be formatted, but it may contain fairly
                 large amounts of whitespace for wide columns.

       "fmtsub" => \&fmt_sub
                 A reference to a subroutine which formats a value, according
                 to its type, width, precision, and the current column width.
                 It is invoked either with a fixed list of arguments, or with
                 a hash-array of parameter and value pairs.

                   $string = &fmt_sub { I<parameter> => I<value>, ... };

                   $string = &fmt_sub($value, $type, $max_width, $width, $precision)

                 If \&fmt_sub is omitted, then a default subroutine, ShowTabl-
                 eValue, will be used, which will use Perl's standard string
                 formatting rules.

                 The arguments to \&fmt_sub, either as values passed in a
                 fixed order, or as part of the parameter value pair, are
                 described in the section on "ShowTableValue below.

       "max_width" => number,
                 The maximum table width, including the table formatting char-
                 acters.  If not given, defaults to the global variable
                 $Max_Table_Width;

       "show_mode" => 'mode',
                 The display mode of the output.  One of five strings: 'Box',
                 'Table', 'Simple', 'List', and 'HTML'.


ShowDatabases

       Show a list of database names.

        ShowDatabases \@dbnames;

        ShowDatabases { 'data' => \@dbnames, parameter => value, ...};

       ShowDatabases is intended to be used to display a list of database
       names, under the column heading of "Databases".  It is a special case
       usage of ShowTable (and can thus be passed any parameter suitable for
       ShowTable.

       The argument, \@dbnames, is a reference to an array of strings, used as
       the values of the single column display.


ShowTables

       Show an array of table names.

        ShowTables \@tblnames;

        ShowTables { 'data' => \@tblnames, parameter => value, ...};

       ShowTables is used to display a list of table names, under the column
       heading of "Tables".  It is a special case usage of ShowTable, and can
       be passed any "ShowTable" argument parameter.


ShowColumns

       Display a table of column names, types, and attributes.

        ShowColumns { parameter => values, ... };

        ShowColumns \@columns, \@col_types, \@col_lengths, \@col_attrs;

       The ShowColumns subroutine displays a table of column names, types,
       lengths, and other attributes in a nicely formatted table.  It is a
       special case usage of ShowTable, and can be passed any argument suit-
       able for "ShowTable";

       The arguments are:

       "columns" = \@columns
                 An array of column names.  This provides the value for the
                 first column of the output.

       "col_types" = \@col_types
                 An array of column types names.  This provides the value for
                 the second column.

       "col_lengths" = \@col_lengths
                 An array of maximum lengths for corresponding columns.  This
                 provides the value for the third column of the output.

       "col_attrs" = \@col_attrs
                 An array of column attributes array references (ie: an array
                 of arrays).  The attributes array for the first column are at
                 "$col_attrs-\>[0]".  The first attribute of the second column
                 is "$col_attrs-\>[1][0]".

       The columns, types, lengths, and attributes are displayed in a table
       with the column headings: "Column", "Type", "Length", and "Attributes".
       This is a special case usage of ShowTable, and can be passed additional
       arguments suitable for "ShowTable".


ShowBoxTable

       Show tabular data in a box.

        ShowBoxTable { parameter = value, ... };

        ShowBoxTable \@titles, \@types, \@widths, \&row_sub  [, [ \&fmt_sub ]
       [, $max_width ] ];

       The ShowBoxTable displays tabular data in titled columns using a "box"
       of ASCII graphics, looking something like this:

               +------------+----------+-----+----------+
               | Column1    | Column2  | ... | ColumnN  |
               +------------+----------+-----+----------+
               | Value11    | Value12  | ... | Value 1M |
               | Value21    | Value22  | ... | Value 2M |
               | Value31    | Value32  | ... | Value 3M |
               |  ...       |  ...     | ... |  ...     |
               | ValueN1    | ValueN2  | ... | Value NM |
               +------------+----------+-----+----------+

       The arguments are the same as with "ShowTable".  If the @titles array
       is empty, the header row is omitted.


ShowSimpleTable

       Display a table of data using a simple table format.

        ShowSimpleTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub];

        ShowSimpleTable { parameter => values, ... };

       The ShowSimpleTable subroutine formats data into a simple table of
       aligned columns, in the following example:

          Column1  Column2  Column3
          -------  -------  -------
          Value1   Value2   Value3
          Value12  Value22  Value32

       Columns are auto-sized by the data's widths, plus two spaces between
       columns.  Values which are too long for the maximum colulmn width are
       wrapped within the column.


ShowHTMLTable

       Display a table of data nicely using HTML tables.

        ShowHTMLTable { parameter => value, ... };

        ShowHTMLTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub [,
       $max_width [, \%URL_Keys [, $no_escape [, \@title_formats [,
       \@data_formats [, $table_attrs ] ] ] ] ] ] ];

       .PP The ShowHTMLTable displays one or more rows of columns of data
       using the HTML "\<TABLE\"> feature.  In addition to the usual parameter
       arguments of "ShowTable", the following parameter arguments are
       defined:

       "url_keys" => \%URL_Keys,
                 This is a hash array of column names (titles) and correspond-
                 ing base URLs.  The values of any column names or indexes
                 occuring as keys in the hash array will be generated as
                 hypertext anchors using the associated printf-like string as
                 the base URL. Either the column name or the column index
                 (beginning with 1) may be used as the hash key.

                 In the string value, these macros can be substituted:

                 "%K" is replaced with the column name.

                 "%V" is replaced with the column value;

                 "%I" is replaced with the column index.

                 For example, if we define the array:

                     $base_url = "http://www.$domain/cgi/lookup?col=%K?val=%V";
                     %url_cols = ('Author' => $base_url,
                                  'Name'   => $base_url);

                 Then, the values in the "Author" column will be generated
                 with the following HTML text:

                     <A HREF="http://www.$domain/cgi/lookup?col=Author?val=somevalue>somevalue</A>

                 and the values in the "Name" column will be generated with
                 the URL:

                     <A HREF="http://www.$domain/cgi/lookup?col=Name?val=othervalue>othervalue</A>

                 If this variable is not given, it will default to the global
                 variable "\%URL_Keys".

       "no_escape" => boolean,
                 Unless $no_escape is set, HTML-escaping is performed on the
                 data values in order to properly display the special HTML
                 formatting characters : '\<', '\>', and '&'.  If you wish to
                 display data with embedded HTML text, you must set
                 $no_escape.

                 Enabling embedded HTML, turns on certain heuristics which
                 enable the user to more completely define appearance of the
                 table.  For instance, any "\<TR\"> tokens found embedded
                 *anywhere* within a row of data will be placed at the front
                 of the row, within the generated "\<TR\">.

                 Similarly, a row of data containing the "\<THEAD\"> or
                 "\<TFOOT\"> tokens, and their closing counterparts, will
                 begin and end, respectively a table header or footer data.

       "title_formats" => \@title_formats,
       "tformats" => \@title_formats,
                 An array of HTML formatting elements for the column titles,
                 one for each column.  Each array element is a list of one or
                 more HTML elements, given as "\<ELEMENT\"> or plainly, "ELE-
                 MENT", and separated by a comma ',', semi-colon ';', or ver-
                 tical bar '|'.  Each given HTML element is prepended to the
                 corresponding column title, in the order given.  The corre-
                 sponding HTML closing elements are appended in the opposite
                 order.

                 For example, if \@title_formats contains the two elements:

                     [ 'FONT SIZE=+2,BOLD', 'FONT COLOR=red,EM' ]

                 then the text output for the title of the first column would
                 be:

                     <FONT SIZE=+2><BOLD>I<column_1_title></BOLD></FONT>

                 If "title_formats" is omitted, the global variable
                 @Title_Formats is used by default.

       "data_formats" => \@data_formats,
       "dformats" => \@data_formats,
                 Similar to "title_formats", this array provides HTML format-
                 ting for the columns of each row of data.  If "data_formats"
                 is omitted or null, then the global variable \@Data_Formats
                 is used by default.

       "table_attrs" => $table_attrs,
                 This variable defines a string of attributes to be inserted
                 within the "\<TABLE\"> token.  For example, if the user
                 wishes to have no table border:

                     ShowHTMLTable {
                         ...
                         table_attrs => 'BORDER=0',
                         ...
                     };


ShowListTable

       Display a table of data using a list format.

        ShowListTable { parameter => value, ... };

        ShowListTable \@titles, \@types, \@widths, \&row_sub [, \&fmt_sub [,
       $max_width [, $wrap_margin ] ] ];

       The arguments for ShowListTable are the same as for "ShowTable", except
       for those described next.

       "max_width" = number,
       "wrap_margin" = number,
                 Lines are truncated, and wrapped when their length exceeds
                 $max_width.  Wrapping is done on a word-basis, unless the
                 resulting right margin exceeds $wrap_margin, in which case
                 the line is simply truncated at the $max_width limit.

                 The $max_width variable defaults to $Max_List_Width.  The
                 $wrap_margin defaults to $List_Wrap_Margin.

       In List mode, columns (called "fields" in List mode) are displayed wth
       a field name and value pair per line, with records being one or more
       fields .  In other words, the output of a table would look something
       like this:

           Field1_1: Value1_1
           Field1_2: Value1_2
           Field1_3: Value1_3
           ...
           Field1-N: Value1_M
           <empty line>
           Field2_1: Value2_1
           Field2_2: Value2_2
           Field2_3: Value2_3
           ...
           Field2_N: Value2_N
           ...
           FieldM_1: ValueM_1
           FieldM_2: ValueM_2
           ...
           FieldM_N: ValueM_N
           <empty line>
           <empty line>

       Characteristics of List mode:

       o         two empty lines indicate the end of data.

       o         An empty field (column) may be omitted, or may have a label,
                 but no data.

       o         A long line can be continue by a null field (column):

                     Field2: blah blah blah
                           : blah blah blah

       o         On a continuation, the null field is an arbitrary number of
                 leading white space, a colon ':', a single blank or tab, fol-
                 lowed by the continued text.

       o         Embedded newlines are indicated by the escape mechanism "\n".
                 Similarly, embedded tabs are indicated with "\t", returns
                 with "\r".

       o         If the @titles array is empty, the field names ""Field_"NN"
                 are used instead.


ShowRow

       Fetch rows successively from one or more columns of data.

        ShowRow $rewindflag, \$index, $col_array_1 [, $col_array_2, ...;]

       The ShowRow subroutine returns a row of data from one or more columns
       of data.  It is designed to be used as a callback routine, within the
       ShowTable routine.   It can be used to select elements from one or more
       array reference arguments.

       If passed two or more array references as arguments, elements of the
       arrays selected by $index are returned as the "row" of data.

       If a single array argument is passed, and each element of the array is
       itself an array, the subarray is returned as the "row" of data.

       If the $rewindflag flag is set, then the $index pointer is reset to
       zero, and "true" is returned (a scalar 1).  This indicates that the
       data is rewindable to the ShowTable routines.

       When the $rewindflag is not set, then the current row of data, as
       determined by $index is returned, and $index will have been incre-
       mented.

       An actual invocation (from ShowColumns) is:

         ShowTable \@titles, \@types, \@lengths,
             sub { &ShowRow( $_[0], \$current_row, $col_names, $col_types,
                             $col_lengths, \@col_attrs); };

       In the example above, after each invocation, the $current_row argument
       will have been incremented.


ShowTableValue

       Prepare and return a formatted representation of a value.  A value
       argument, using its corresponding type, effective width, and precision
       is formatted into a field of a given maximum width.

        $fmt = ShowTableValue $value, $type, $max_width, $width, $precision,
       $showmode;

       "width" => $width
       $width    The width of the current value.  If omittied, $max_width is
                 assumed.

       "precision" => $precision
       $precision
                 The number of decimal digits; zero is assumed if omittied.

       "value" => $value
       $value    The value to be formatted.

       $type     The type name of the value; eg: "char", "varchar", "int",
                 etc.

       "maxwidth" => $max_width
       $max_width
                 The maximum width of any value in the current value's column.
                 If $width is zero or null, $max_width is used by default.
                 $max_width is also used as a minimum width, in case $width is
                 a smaller value.

       $width    The default width of the value, obtained from the width spec-
                 ification of the column in which this value occurs.

       $precision
                 The precision specification, if any, from the column width
                 specification.

       $showmode The mode of the output: one of "table", "list", "box", or
                 "html".  Currently, only the "html" mode is significant: it
                 is used to avoid using HTML tokens as part of the formatted
                 text and length calculations.


PlainText

        $plaintext = &PlainText($htmltext);

        &PlainText

       This function removes any HTML formatting sequences from the input
       argument, or from $_ if no argument is given.  The resulting plain text
       is returned as the result.


VARIABLES

       The following variables may be set by the user to affect the display
       (with the defaults enclosed in square brackets [..]):

       $Show_Mode [Box]
                 This is the default display mode when using ShowTable.  The
                 environment variable, $ENV{'SHOW_MODE'}, is used when this
                 variable is null or the empty string.  The possible values
                 for this variable are: "Box", "List", "Table", and "HTML".
                 Case is insignificant.

       $List_Wrap_Margin [2]
                 This variable's value determines how large a margin to keep
                 before wrarpping a long value's display in a column.  This
                 value is only used in "List" mode.

       $Max_List_Width [80]
                 This variable, used in "List" mode, is used to determine how
                 long an output line may be before wrapping it.  The environ-
                 ment variable, $ENV{'COLUMNS'}, is used to define this value
                 when it is null.

       $Max_Table_Width ['']
                 This variable, when set, causes all tables to have their col-
                 umns scaled such that their total combined width does not
                 exceed this value.  When this variable is not set, which is
                 the default case, there is no maximum table width, and no
                 scaling will be done.

       $No_Escape ['']
                 If set, allows embedded HTML text to be included in the data
                 displayed in an HTML-formatted table.  By default, the HTML
                 formatting characters ("<", ">", and "&") occuring in values
                 are escaped.

       %URL_Keys In HTML mode, this variable is used to recognize which col-
                 umns are to be displayed with a corresponding hypertext
                 anchor.  See "ShowHTMLTable" for more details.

       @HTML_Elements
                 An array of HTML elements (as of HTML 3.0) used to recognize
                 and strip for width calculations.

       $HTML_Elements
                 A regular expression string formed from the elements of
                 @HTML_Elements.


INTERNAL SUBROUTINES


get_params

        my $args = &get_params \@argv, \%params, \@arglist;

       Given the @argv originally passed to the calling sub, and the hash of
       named parameters as %params, and the array of parameter names in the
       order expected for a pass-by-value invocation, set the values of each
       of the variables named in @vars.

       If the only element of the @argv is a hash array, then set the vari-
       ables to the values of their corresponding parameters used as keys to
       the hash array.  If the parameter is not a key of the %params hash, and
       is not a key in the global hash %ShowTableParams, then an error is
       noted.

       When @argv has multiple elements, or is not a hash array, set each
       variable, in the order given within @arglist, to the values from the
       @argv, setting the variables named by each value in %params.

       Variables may given either by name or by reference.

       The result is a HASH array reference, either corresponding directly to
       the HASH array passed as the single argument, or one created by associ-
       ating the resulting variable values to the parameter names associated
       with the variable names.


html_formats

        ($prefixes,$suffixes) = html_formats \@html_formats;

       The html_format function takes an array reference of HTML formatting
       elements \@html_formats, and builds two arrays of strings: the first:
       $prefixes, is an array of prefixes containing the corresponding HTML
       formatting elements from \@html_formats, and the second, $suffixes,
       containing the appropriate HTML closing elements, in the opposite
       order.

       The result is designed to be used as prefixes and suffixes for the cor-
       responding titles and column values.

       The array \@html_formats contains lists of HTML formatting elements,
       one for each column (either title or data).  Each array element is a
       list of one or more HTML elements, either given in HTML syntax, or as a
       "plain" name (ie: given as "\<ELEMENT\"> or plainly, "ELEMENT").  Mul-
       tiple elements are separated by a comma ','.

       The resulting array of $prefixes contains the corresponding opening
       elements, in the order given, with the proper HTML element syntax.  The
       resulting array of $suffixes contains the closing elements, in the
       opposite order given, with the proper HTML element syntax.

       For example, if \@html_formats contains the two elements:

           [ 'FONT SIZE=+2,BOLD', 'FONT COLOR=red,EM' ]

       then the resulting two arrays will be returned as:

           [ [ '<FONT SIZE=+2><BOLD>', '<FONT COLOR=red><EM>' ],
             [ '</FONT></BOLD>',       '</FONT></EM>' ] ]


calc_widths

        ($num_cols, $widths, $precision, $max_widths) =  &calc_widths( $width-
       spec, $titles, $rewindable,  $row_sub, $fmt_sub, $types, $showmode,
        $max_width);

       DESCRIPTION

       calc_widths is a generalized subroutine used by all the ShowTable vari-
       ant subroutines to setup internal variables prior to formatting for
       display.  Calc_widths handles the column width and precision analysis,
       including scanning the data (if rewindable) for appropriate default
       values.

       The number of columns in the data is returned, as well as three arrays:
       the declared column widths, the column precision values, and the maxi-
       mum column widths.

       RETURN VALUES

       $num_cols is the number of columns in the data.  If the data is not
                 rewindable, this is computed as the maximum of the number of
                 elements in the $widthspec array and the number of elements
                 in the $titles array.  When the data is rewindable, this is
                 the maximum of the number of columns of each row of data.

       $widths   is the column widths array ref, without the precision specs
                 (if any).  Each column's width value is determined by the
                 original $widthspec value and/or the maximum length of the
                 formatted data for the column.

       $precision
                 is the precision component (if any) of the original $width-
                 spec array ref.  If there was no original precision component
                 from the $widthspec, and the data is rewindable, then the
                 data is examined to determine the maximum default precision.

       $max_widths
                 is the ref to the array of maximum widths for the given col-
                 umns.

       ARGUMENTS

       $widthspec
                 A reference to an array of column width (or length) values,
                 each given as an integer, real number, or a string value of
                 "width.precision".  If a value is zero or null, the length of
                 the corresponding formatted data (if rewindable) and column
                 title length are used to determine a reasonable default.

                 If a column's width portion is a positive, non-zero number,
                 then the column will be this wide, regardless of the values
                 lengths of the data in the column.

                 If the column's width portion is given as a negative number,
                 then the positive value is used as a minimum column width,
                 with no limit on the maximum column width.  In other words,
                 the column will be at least width characters wide.

                 If the data is not rewindable, and a column's width value is
                 null or zero, then the length of the column title is used.
                 This may cause severe wrapping of data in the column, if the
                 column data lengths are much greater than the column title
                 widths.

       $titles   The array ref to the column titles; used to determine the
                 minimum acceptable width, as well as the default number of
                 columns.  If the $titles array is empty, then the $widthspec
                 array is used to determine the default number of columns.

       $rewindable
                 A flag indicating whether or not the data being formatted is
                 rewindable.  If this is true, a pass over the data will be
                 done in order to calculate the maximum lengths of the actual
                 formatted data, using $fmt_sub (below), rather than just rely
                 on the declared column lengths.  This allows for optimal col-
                 umn width adjustments (ie: the actual column widths may be
                 less than the declared column widths).

                 If it is not desired to have the column widths dynamically
                 adjusted, then set the $rewindable argument to 0, even if the
                 data is rewindable.

       $row_sub  The code reference to the subroutine which returns the data;
                 invoked only if $rewindable is non-null.

       $fmt_sub  The subroutine used to determine the length of the data when
                 formatted; if this is omitted or null, the length of the data
                 is used by default.  The $fmt_sub is used only when the data
                 is rewindable.

       $types    An array reference to the types of each of the value columns;
                 used only when $fmt_sub is invoked.

       $showmode A string indicating the mode of the eventual display; one of
                 four strings: ""box"", ""table"", ""list"", and ""html"".
                 Used to adjust widths for formatting requirements.

       $max_width
                 The maximum width of the table being formatted.  If set, and
                 the total sum of the individual columns exceeds this value,
                 the column widths are scaled down uniformly.  If not set
                 (null), no column width scaling is done.


putcell

        $wrapped = &putcell( \@cells, $c, $cell_width, \@prefix, \@suffix,
       $wrap_flag );

       Output the contents of an array cell at $cell[$c], causing text longer
       than $cell_width to be saved for output on subsequent calls.  Prefixing
       the output of each cell's value is a string from the two-element array
       @prefix.  Suffixing each cell's value is a string from the two-element
       array @suffix.  The first element of either array is selected when
       $wrap_flag is zero or null, or when there is no more text in the cur-
       rent to be output.  The second element is selected when $wrap_flag is
       non-zero, and when there is more text in the current cell to be output.

       In the case of text longer than $cell_width, a non-zero value is
       returned.

       Cells with undefined data are not output, nor are the prefix or suffix
       strings.


center

       Center a string within a given width.

        $field = center $string, $width;


max

       Compute the maximum value from a list of values.

        $max = &max( @values );


min

       Compute the minum value from a list of values.

        $min = &min( @values );


max_length

       Compute the maximum length of a set of strings in an array reference.

        $maxlength = &max_length( \@array_ref );


htmltext

       Translate regular text for output into an HTML document.  This means
       certain characters, such as "&", ">", and "<" must be escaped.

        $output = &htmltext( $input [, $allflag ] );

       If $allflag is non-zero, then all characters are escaped.  Normally,
       only the four HTML syntactic break characters are escaped.


out

       Print text followed by a newline.

        out $fmt [, @text ];


put

       Print text (without a trailing newline).

        out $fmt [, @text ];


AUTHOR

       Alan K. Stebbens <aks@sgi.com>


BUGS

       o         Embedded HTML is how the user can insert formatting over-
                 rides.  However, the HTML formatting techniques have not been
                 given much consideration -- feel free to provide constructive
                 feedback.

perl v5.8.6                       1997-03-02                      ShowTable(3)

Man(1) output converted with man2html