Text::Reform(3) User Contributed Perl Documentation Text::Reform(3)NAMEText::Reform - Manual text wrapping and reformatting
VERSION
This document describes version 1.11 of Text::Reform, released May 7,
2003.
SYNOPSIS
use Text::Reform;
print form $template,
$data, $to, $fill, $it, $with;
use Text::Reform qw( tag );
print tag 'B', $enboldened_text;
DESCRIPTION
The "form" sub
The "form()" subroutine may be exported from the module. It takes a
series of format (or "picture") strings followed by replacement values,
interpolates those values into each picture string, and returns the
result. The effect is similar to the inbuilt perl "format" mechanism,
although the field specification syntax is simpler and some of the for‐
matting behaviour is more sophisticated.
A picture string consists of sequences of the following characters:
< Left-justified field indicator. A series of two or more
sequential <'s specify a left-justified field to be filled by a
subsequent value. A single < is formatted as the literal char‐
acter '<'
> Right-justified field indicator. A series of two or more
sequential >'s specify a right-justified field to be filled by
a subsequent value. A single > is formatted as the literal
character '>'
<<<>>> Fully-justified field indicator. Field may be of any width,
and brackets need not balance, but there must be at least 2 '<'
and 2 '>'.
^ Centre-justified field indicator. A series of two or more
sequential ^'s specify a centred field to be filled by a subse‐
quent value. A single ^ is formatted as the literal character
'^'
>>>.<<<<
A numerically formatted field with the specified number of dig‐
its to either side of the decimal place. See "Numerical format‐
ting" below.
[ Left-justified block field indicator. Just like a < field,
except it repeats as required on subsequent lines. See below.
A single [ is formatted as the literal character '['
] Right-justified block field indicator. Just like a > field,
except it repeats as required on subsequent lines. See below.
A single ] is formatted as the literal character ']'
[[[]]] Fully-justified block field indicator. Just like a <<<>>>
field, except it repeats as required on subsequent lines. See
below. Field may be of any width, and brackets need not bal‐
ance, but there must be at least 2 '[' and 2 ']'.
⎪ Centre-justified block field indicator. Just like a ^ field,
except it repeats as required on subsequent lines. See below.
A single ⎪ is formatted as the literal character '⎪'
]]].[[[[
A numerically formatted block field with the specified number
of digits to either side of the decimal place. Just like a
>>>.<<<< field, except it repeats as required on subsequent
lines. See below.
~ A one-character wide block field.
\ Literal escape of next character (e.g. "\~" is formatted as
'~', not a one character wide block field).
Any other character
That literal character.
Any substitution value which is "undef" (either explicitly so, or
because it is missing) is replaced by an empty string.
Controlling line filling.
Note that, unlike the a perl "format", "form" preserves whitespace
(including newlines) unless called with certain options.
The "squeeze" option (when specified with a true value) causes any
sequence of spaces and/or tabs (but not newlines) in an interpolated
string to be replaced with a single space.
A true value for the "fill" option causes (only) newlines to be
squeezed.
To minimize all whitespace, you need to specify both options. Hence:
$format = "EG> [[[[[[[[[[[[[[[[[[[[[";
$data = "h e\t l lo\nworld\t\t\t\t\t";
print form $format, $data; # all whitespace preserved:
#
# EG> h e l lo
# EG> world
print form {squeeze=>1}, # only newlines preserved:
$format, $data; #
# EG> h e l lo
# EG> world
print form {fill=>1}, # only spaces/tabs preserved:
$format, $data; #
# EG> h e l lo world
print form {squeeze=>1, fill=>1}, # no whitespace preserved:
$format, $data; #
# EG> h e l lo world
Whether or not filling or squeezing is in effect, "form" can also be
directed to trim any extra whitespace from the end of each line it for‐
mats, using the "trim" option. If this option is specified with a true
value, every line returned by "form" will automatically have the sub‐
stitution "s/[ \t]+$//gm" applied to it.
Hence:
print length form "[[[[[[[[[[", "short";
# 11
print length form {trim=>1}, "[[[[[[[[[[", "short";
# 6
It is also possible to control the character used to fill lines that
are too short, using the 'filler' option. If this option is specified
the value of the 'filler' flag is used as the fill string, rather than
the default " ".
For example:
print form { filler=>'*' },
"Pay bearer: ^^^^^^^^^^^^^^^^^^^",
'$123.45';
prints:
Pay bearer: ******$123.45******
If the filler string is longer than one character, it is truncated to
the appropriate length. So:
print form { filler=>'-->' },
"Pay bearer: ]]]]]]]]]]]]]]]]]]]",
['$1234.50', '$123.45', '$12.34'];
prints:
Pay bearer: ->-->-->-->$1234.50
Pay bearer: -->-->-->-->$123.45
Pay bearer: >-->-->-->-->$12.34
If the value of the 'filler' option is a hash, then it's 'left' and
'right' entries specify separate filler strings for each side of an
interpolated value. So:
print form { filler=>{left=>'->', right=>'*'} },
"Pay bearer: <<<<<<<<<<<<<<<<<<",
'$123.45',
"Pay bearer: >>>>>>>>>>>>>>>>>>",
'$123.45',
"Pay bearer: ^^^^^^^^^^^^^^^^^^",
'$123.45';
prints:
Pay bearer: $123.45***********
Pay bearer: >->->->->->$123.45
Pay bearer: >->->$123.45******
Temporary and permanent default options
If "form" is called with options, but no template string or data, it
resets it's defaults to the options specified. If called in a void con‐
text:
form { squeeze => 1, trim => 1 };
the options become permanent defaults.
However, when called with only options in non-void context, "form"
resets its defaults to those options and returns an object. The reset
default values persist only until that returned object is destroyed.
Hence to temporarily reset "form"'s defaults within a single subrou‐
tine:
sub single {
my $tmp = form { squeeze => 1, trim => 1 };
# do formatting with the obove defaults
} # form's defaults revert to previous values as $tmp object destroyed
Multi-line format specifiers and interleaving
By default, if a format specifier contains two or more lines (i.e. one
or more newline characters), the entire format specifier is repeatedly
filled as a unit, until all block fields have consumed their corre‐
sponding arguments. For example, to build a simple look-up table:
my @values = (1..12);
my @squares = map { sprintf "%.6g", $_**2 } @values;
my @roots = map { sprintf "%.6g", sqrt($_) } @values;
my @logs = map { sprintf "%.6g", log($_) } @values;
my @inverses = map { sprintf "%.6g", 1/$_ } @values;
print form
" N N**2 sqrt(N)log(N) 1/N",
"=====================================================",
"⎪ [[ ⎪ [[[ ⎪ [[[[[[[[[[ ⎪ [[[[[[[[[ ⎪ [[[[[[[[[ ⎪
-----------------------------------------------------",
\@values, \@squares, \@roots, \@logs, \@inverses;
The multiline format specifier:
"⎪ [[ ⎪ [[[ ⎪ [[[[[[[[[[ ⎪ [[[[[[[[[ ⎪ [[[[[[[[[ ⎪
-----------------------------------------------------",
is treated as a single logical line. So "form" alternately fills the
first physical line (interpolating one value from each of the arrays)
and the second physical line (which puts a line of dashes between each
row of the table) producing:
N N**2 sqrt(N)log(N) 1/N
=====================================================
⎪ 1 ⎪ 1 ⎪ 1 ⎪ 0 ⎪ 1 ⎪
-----------------------------------------------------
⎪ 2 ⎪ 4 ⎪ 1.41421 ⎪ 0.693147 ⎪ 0.5 ⎪
-----------------------------------------------------
⎪ 3 ⎪ 9 ⎪ 1.73205 ⎪ 1.09861 ⎪ 0.333333 ⎪
-----------------------------------------------------
⎪ 4 ⎪ 16 ⎪ 2 ⎪ 1.38629 ⎪ 0.25 ⎪
-----------------------------------------------------
⎪ 5 ⎪ 25 ⎪ 2.23607 ⎪ 1.60944 ⎪ 0.2 ⎪
-----------------------------------------------------
⎪ 6 ⎪ 36 ⎪ 2.44949 ⎪ 1.79176 ⎪ 0.166667 ⎪
-----------------------------------------------------
⎪ 7 ⎪ 49 ⎪ 2.64575 ⎪ 1.94591 ⎪ 0.142857 ⎪
-----------------------------------------------------
⎪ 8 ⎪ 64 ⎪ 2.82843 ⎪ 2.07944 ⎪ 0.125 ⎪
-----------------------------------------------------
⎪ 9 ⎪ 81 ⎪ 3 ⎪ 2.19722 ⎪ 0.111111 ⎪
-----------------------------------------------------
⎪ 10 ⎪ 100 ⎪ 3.16228 ⎪ 2.30259 ⎪ 0.1 ⎪
-----------------------------------------------------
⎪ 11 ⎪ 121 ⎪ 3.31662 ⎪ 2.3979 ⎪ 0.0909091 ⎪
-----------------------------------------------------
⎪ 12 ⎪ 144 ⎪ 3.4641 ⎪ 2.48491 ⎪ 0.0833333 ⎪
-----------------------------------------------------
This implies that formats and the variables from which they're filled
need to be interleaved. That is, a multi-line specification like this:
print form
"Passed: ##
[[[[[[[[[[[[[[[ # single format specification
Failed: # (needs two sets of data)
[[[[[[[[[[[[[[[", ##
\@passes, \@fails; ## data for previous format
would print:
Passed:
<pass 1>
Failed:
<fail 1>
Passed:
<pass 2>
Failed:
<fail 2>
Passed:
<pass 3>
Failed:
<fail 3>
because the four-line format specifier is treated as a single unit, to
be repeatedly filled until all the data in @passes and @fails has been
consumed.
Unlike the table example, where this unit filling correctly put a line
of dashes between lines of data, in this case the alternation of passes
and fails is probably not the desired effect.
Judging by the labels, it is far more likely that the user wanted:
Passed:
<pass 1>
<pass 2>
<pass 3>
Failed:
<fail 4>
<fail 5>
<fail 6>
To achieve that, either explicitly interleave the formats and their
data sources:
print form
"Passed:", ## single format (no data required)
" [[[[[[[[[[[[[[[", ## single format (needs one set of data)
\@passes, ## data for previous format
"Failed:", ## single format (no data required)
" [[[[[[[[[[[[[[[", ## single format (needs one set of data)
\@fails; ## data for previous format
or instruct "form" to do it for you automagically, by setting the
'interleave' flag true:
print form {interleave=>1}
"Passed: ##
[[[[[[[[[[[[[[[ # single format
Failed: # (needs two sets of data)
[[[[[[[[[[[[[[[", ##
## data to be automagically interleaved
\@passes, \@fails; # as necessary between lines of previous
## format
How "form" hyphenates
Any line with a block field repeats on subsequent lines until all block
fields on that line have consumed all their data. Non-block fields on
these lines are replaced by the appropriate number of spaces.
Words are wrapped whole, unless they will not fit into the field at
all, in which case they are broken and (by default) hyphenated. Simple
hyphenation is used (i.e. break at the N-1th character and insert a
'-'), unless a suitable alternative subroutine is specified instead.
Words will not be broken if the break would leave less than 2 charac‐
ters on the current line. This minimum can be varied by setting the
'minbreak' option to a numeric value indicating the minumum total bro‐
ken characters (including hyphens) required on the current line. Note
that, for very narrow fields, words will still be broken (but unhyphen‐
ated). For example:
print form '~', 'split';
would print:
s
p
l
i
t
whilst:
print form {minbreak=>1}, '~', 'split';
would print:
s-
p-
l-
i-
t
Alternative breaking subroutines can be specified using the "break"
option in a configuration hash. For example:
form { break => \&my_line_breaker }
$format_str,
@data;
"form" expects any user-defined line-breaking subroutine to take three
arguments (the string to be broken, the maximum permissible length of
the initial section, and the total width of the field being filled).
The "hypenate" sub must return a list of two strings: the initial (bro‐
ken) section of the word, and the remainder of the string respec‐
tively).
For example:
sub tilde_break = sub($$$)
{
(substr($_[0],0,$_[1]-1).'~', substr($_[0],$_[1]-1));
}
form { break => \&tilde_break }
$format_str,
@data;
makes '~' the hyphenation character, whilst:
sub wrap_and_slop = sub($$$)
{
my ($text, $reqlen, $fldlen) = @_;
if ($reqlen==$fldlen) { $text =~ m/\A(\s*\S*)(.*)/s }
else { ("", $text) }
}
form { break => \&wrap_and_slop }
$format_str,
@data;
wraps excessively long words to the next line and "slops" them over the
right margin if necessary.
The Text::Reform package provides three functions to simplify the use
of variant hyphenation schemes. The exportable subroutine
"Text::Reform::break_wrap" generates a reference to a subroutine imple‐
menting the "wrap-and-slop" algorithm shown in the last example, which
could therefore be rewritten:
use Text::Reform qw( form break_wrap );
form { break => break_wrap }
$format_str,
@data;
The subroutine "Text::Reform::break_with" takes a single string argu‐
ment and returns a reference to a sub which hyphenates by cutting off
the text at the right margin and appending the string argument. Hence
the first of the two examples could be rewritten:
use Text::Reform qw( form break_with );
form { break => break_with('~') }
$format_str,
@data;
The subroutine "Text::Reform::break_at" takes a single string argument
and returns a reference to a sub which hyphenates by breaking immedi‐
ately after that string. For example:
use Text::Reform qw( form break_at );
form { break => break_at('-') }
"[[[[[[[[[[[[[[",
"The Newton-Raphson methodology";
# returns:
#
# "The Newton-
# Raphson
# methodology"
Note that this differs from the behaviour of "break_with", which would
be:
form { break => break_with('-') }
"[[[[[[[[[[[[[[",
"The Newton-Raphson methodology";
# returns:
#
# "The Newton-R-
# aphson metho-
# dology"
Hence "break_at" is generally a better choice.
"break_at" also takes an 'except' option, which tells the resulting
subroutine not to break in the middle of certain strings. For example:
form { break => break_at('-', {except=>qr/Newton-Raphson/}) }
"[[[[[[[[[[[[[[",
"The Newton-Raphson methodology";
# returns:
#
# "The
# Newton-Raphson
# methodology"
This option is particularly useful for preserving URLs.
The subroutine "Text::Reform::break_TeX" returns a reference to a sub
which hyphenates using Jan Pazdziora's TeX::Hyphen module. For example:
use Text::Reform qw( form break_wrap );
form { break => break_TeX }
$format_str,
@data;
Note that in the previous examples there is no leading '\&' before
"break_wrap", "break_with", or "break_TeX", since each is being
directly called (and returns a reference to some other suitable subrou‐
tine);
The "form" formatting algorithm
The algorithm "form" uses is:
1. If interleaving is specified, split the first string in the
argument list into individual format lines and add a
terminating newline (unless one is already present).
Otherwise, treat the entire string as a single "line" (like
/s does in regexes)
2. For each format line...
2.1. determine the number of fields and shift
that many values off the argument list and
into the filling list. If insufficient
arguments are available, generate as many
empty strings as are required.
2.2. generate a text line by filling each field
in the format line with the initial contents
of the corresponding arg in the filling list
(and remove those initial contents from the arg).
2.3. replace any <,>, or ^ fields by an equivalent
number of spaces. Splice out the corresponding
args from the filling list.
2.4. Repeat from step 2.2 until all args in the
filling list are empty.
3. concatenate the text lines generated in step 2
4. repeat from step 1 until the argument list is empty
"form" examples
As an example of the use of "form", the following:
$count = 1;
$text = "A big long piece of text to be formatted exquisitely";
print form q
q{ ⎪⎪⎪⎪ <<<<<<<<<< },
$count, $text,
q{ ---------------- },
q{ ^^^^ ]]]]]]]]]]⎪ },
$count+11, $text,
q{ =
]]].[[[ },
"123 123.4\n123.456789";
produces the following output:
1 A big long
----------------
12 piece of⎪
text to be⎪
formatted⎪
exquisite-⎪
ly⎪
=
123.0
=
123.4
=
123.456
Note that block fields in a multi-line format string, cause the entire
multi-line format to be repeated as often as necessary.
Picture strings and replacement values are interleaved in the tradi‐
tional "format" format, but care is needed to ensure that the correct
number of substitution values are provided. Another example:
$report = form
'Name Rank Serial Number',
'==== ==== =============',
'<<<<<<<<<<<<< ^^^^ <<<<<<<<<<<<<',
$name, $rank, $serial_number,
''
'Age Sex Description',
'=== === ===========',
'^^^ ^^^ [[[[[[[[[[[',
$age, $sex, $description;
How "form" consumes strings
Unlike "format", within "form" non-block fields do consume the text
they format, so the following:
$text = "a line of text to be formatted over three lines";
print form "<<<<<<<<<<\n <<<<<<<<\n <<<<<<\n",
$text, $text, $text;
produces:
a line of
text to
be fo-
not:
a line of
a line
a line
To achieve the latter effect, convert the variable arguments to inde‐
pendent literals (by double-quoted interpolation):
$text = "a line of text to be formatted over three lines";
print form "<<<<<<<<<<\n <<<<<<<<\n <<<<<<\n",
"$text", "$text", "$text";
Although values passed from variable arguments are progressively con‐
sumed within "form", the values of the original variables passed to
"form" are not altered. Hence:
$text = "a line of text to be formatted over three lines";
print form "<<<<<<<<<<\n <<<<<<<<\n <<<<<<\n",
$text, $text, $text;
print $text, "\n";
will print:
a line of
text to
be fo-
a line of text to be formatted over three lines
To cause "form" to consume the values of the original variables passed
to it, pass them as references. Thus:
$text = "a line of text to be formatted over three lines";
print form "<<<<<<<<<<\n <<<<<<<<\n <<<<<<\n",
\$text, \$text, \$text;
print $text, "\n";
will print:
a line of
text to
be fo-
rmatted over three lines
Note that, for safety, the "non-consuming" behaviour takes precedence,
so if a variable is passed to "form" both by reference and by value,
its final value will be unchanged.
Numerical formatting
The ">>>.<<<" and "]]].[[[" field specifiers may be used to format
numeric values about a fixed decimal place marker. For example:
print form '(]]]]].[[)', <<EONUMS;
1
1.0
1.001
1.009
123.456
1234567
one two
EONUMS
would print:
( 1.0 )
( 1.0 )
( 1.00)
( 1.01)
( 123.46)
(#####.##)
(?????.??)
(?????.??)
Fractions are rounded to the specified number of places after the deci‐
mal, but only significant digits are shown. That's why, in the above
example, 1 and 1.0 are formatted as "1.0", whilst 1.001 is formatted as
"1.00".
You can specify that the maximal number of decimal places always be
used by giving the configuration option 'numeric' a value that matches
/\bAllPlaces\b/i. For example:
print form { numeric => AllPlaces },
'(]]]]].[[)', <<'EONUMS';
1
1.0
EONUMS
would print:
( 1.00)
( 1.00)
Note that although decimal digits are rounded to fit the specified
width, the integral part of a number is never modified. If there are
not enough places before the decimal place to represent the number, the
entire number is replaced with hashes.
If a non-numeric sequence is passed as data for a numeric field, it is
formatted as a series of question marks. This querulous behaviour can
be changed by giving the configuration option 'numeric' a value that
matches /\bSkipNaN\b/i in which case, any invalid numeric data is sim‐
ply ignored. For example:
print form { numeric => 'SkipNaN' }
'(]]]]].[[)',
<<EONUMS;
1
two three
4
EONUMS
would print:
( 1.0 )
( 4.0 )
Filling block fields with lists of values
If an argument corresponding to a field is an array reference, then
"form" automatically joins the elements of the array into a single
string, separating each element with a newline character. As a result,
a call like this:
@values = qw( 1 10 100 1000 );
print form "(]]]].[[)", \@values;
will print out
( 1.00)
( 10.00)
( 100.00)
(1000.00)
as might be expected.
Note however that arrays must be passed by reference (so that "form"
knows that the entire array holds data for a single field). If the pre‐
vious example had not passed @values by reference:
@values = qw( 1 10 100 1000 );
print form "(]]]].[[)", @values;
the output would have been:
( 1.00)
10
100
1000
This is because @values would have been interpolated into "form"'s
argument list, so only $value[0] would have been used as the data for
the initial format string. The remaining elements of @value would have
been treated as separate format strings, and printed out "verbatim".
Note too that, because arrays must be passed using a reference, their
original contents are consumed by "form", just like the contents of
scalars passed by reference.
To avoid having an array consumed by "form", pass it as an anonymous
array:
print form "(]]]].[[)", [@values];
Headers, footers, and pages
The "form" subroutine can also insert headers, footers, and page-feeds
as it formats. These features are controlled by the "header", "footer",
"pagefeed", "pagelen", and "pagenum" options.
The "pagenum" option takes a scalar value or a reference to a scalar
variable and starts page numbering at that value. If a reference to a
scalar variable is specified, the value of that variable is updated as
the formatting proceeds, so that the final page number is available in
it after formatting. This can be useful for multi-part reports.
The "pagelen" option specifies the total number of lines in a page
(including headers, footers, and page-feeds).
The "pagewidth" option specifies the total number of columns in a page.
If the "header" option is specified with a string value, that string is
used as the header of every page generated. If it is specified as a
reference to a subroutine, that subroutine is called at the start of
every page and its return value used as the header string. When called,
the subroutine is passed the current page number.
Likewise, if the "footer" option is specified with a string value, that
string is used as the footer of every page generated. If it is speci‐
fied as a reference to a subroutine, that subroutine is called at the
start of every page and its return value used as the footer string.
When called, the footer subroutine is passed the current page number.
Both the header and footer options can also be specified as hash refer‐
ences. In this case the hash entries for keys "left", "centre" (or
"center"), and "right" specify what is to appear on the left, centre,
and right of the header/footer. The entry for the key "width" specifies
how wide the footer is to be. If the "width" key is omitted, the
"pagewidth" configuration option (which defaults to 72 characters) is
used.
The "left", "centre", and "right" values may be literal strings, or
subroutines (just as a normal header/footer specification may be.) See
the second example, below.
Another alternative for header and footer options is to specify them as
a subroutine that returns a hash reference. The subroutine is called
for each page, then the resulting hash is treated like the hashes
described in the preceding paragraph. See the third example, below.
The "pagefeed" option acts in exactly the same way, to produce a page‐
feed which is appended after the footer. But note that the pagefeed is
not counted as part of the page length.
All three of these page components are recomputed at the start of each
new page, before the page contents are formatted (recomputing the
header and footer first makes it possible to determine how many lines
of data to format so as to adhere to the specified page length).
When the call to "form" is complete and the data has been fully format‐
ted, the footer subroutine is called one last time, with an extra argu‐
ment of 1. The string returned by this final call is used as the final
footer.
So for example, a 60-line per page report, starting at page 7, with
appropriate headers and footers might be set up like so:
$page = 7;
form { header => sub { "Page $_[0]\n\n" },
footer => sub { my ($pagenum, $lastpage) = @_;
return "" if $lastpage;
return "-"x50 . "\n"
.form ">"x50, "...".($pagenum+1);
},
pagefeed => "\n\n",
pagelen => 60
pagenum => \$page,
},
$template,
@data;
Note the recursive use of "form" within the "footer" option!
Alternatively, to set up headers and footers such that the running head
is right justified in the header and the page number is centred in the
footer:
form { header => { right => "Running head" },
footer => { centre => sub { "Page $_[0]" } },
pagelen => 60
},
$template,
@data;
The footer in the previous example could also have been specified the
other way around, as a subroutine that returns a hash (rather than a
hash containing a subroutine):
form { header => { right => "Running head" },
footer => sub { return {centre => "Page $_[0]"} },
pagelen => 60
},
$template,
@data;
The "cols" option
Sometimes data to be used in a "form" call needs to be extracted from a
nested data structure. For example, whilst it's easy to print a table
if you already have the data in columns:
@name = qw(Tom Dick Harry);
@score = qw( 88 54 99);
@time = qw( 15 13 18);
print form
'-------------------------------',
'Name Score Time',
'-------------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
\@name, \@score, \@time;
if the data is aggregrated by rows:
@data = (
{ name=>'Tom', score=>88, time=>15 },
{ name=>'Dick', score=>54, time=>13 },
{ name=>'Harry', score=>99, time=>18 },
);
you need to do some fancy mapping before it can be fed to "form":
print form
'-------------------------------',
'Name Score Time',
'-------------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
[map $$_{name}, @data],
[map $$_{score}, @data],
[map $$_{time} , @data];
Or you could just use the 'cols' option:
use Text::Reform qw(form columns);
print form
'-------------------------------',
'Name Score Time',
'-------------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
{ cols => [qw(name score time)],
from => \@data
};
This option takes an array of strings that specifies the keys of the
hash entries to be extracted into columns. The 'from' entry (which must
be present) also takes an array, which is expected to contain a list of
references to hashes. For each key specified, this option inserts into
"form"'s argument list a reference to an array containing the entries
for that key, extracted from each of the hash references supplied by
'from'. So, for example, the option:
{ cols => [qw(name score time)],
from => \@data
}
is replaced by three array references, the first containing the 'name'
entries for each hash inside @data, the second containing the 'score'
entries for each hash inside @data, and the third containing the 'time'
entries for each hash inside @data.
If, instead, you have a list of arrays containing the data:
@data = (
# Time Name Score
[ 15, 'Tom', 88 ],
[ 13, 'Dick', 54 ],
[ 18, 'Harry', 99 ],
);
the 'cols' option can extract the appropriate columns for that too. You
just specify the required indices, rather than keys:
print form
'-----------------------------',
'Name Score Time',
'-----------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
{ cols => [1,2,0],
from => \@data
}
Note that the indices can be in any order, and the resulting arrays are
returned in the same order.
If you need to merge columns extracted from two hierarchical data
structures, just concatenate the data structures first, like so:
print form
'---------------------------------------',
'Name Score Time Ranking
'---------------------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪ ⎪⎪⎪⎪⎪⎪⎪',
{ cols => [1,2,0],
from => [@data, @olddata],
}
Of course, this only works if the columns are in the same positions in
both data sets (and both datasets are stored in arrays) or if the col‐
umns have the same keys (and both datasets are in hashes). If not, you
would need to format each dataset separately, like so:
print form
'-----------------------------',
'Name Score Time'
'-----------------------------',
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
{ cols=>[1,2,0], from=>\@data },
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
{ cols=>[3,8,1], from=>\@olddata },
'[[[[[[[[[[[[[[ ⎪⎪⎪⎪⎪ ⎪⎪⎪⎪',
{ cols=>[qw(name score time)], from=>\@otherdata };
The "tag" sub
The "tag" subroutine may be exported from the module. It takes two
arguments: a tag specifier and a text to be entagged. The tag specifier
indicates the indenting of the tag, and of the text. The sub generates
an end-tag (using the usual "/tag" variant), unless an explicit end-tag
is provided as the third argument.
The tag specifier consists of the following components (in order):
An optional vertical spacer (zero or more whitespace-separated new‐
lines)
One or more whitespace characters up to a final mandatory newline.
This vertical space is inserted before the tag and after the end-
tag
An optional tag indent
Zero or more whitespace characters. Both the tag and the end-tag
are indented by this whitespace.
An optional left (opening) tag delimiter
Zero or more non-"word" characters (not alphanumeric or '_'). If
the opening delimiter is omitted, the character '<' is used.
A tag
One or more "word" characters (alphanumeric or '_').
Optional tag arguments
Any number of any characters
An optional right (closing) tag delimiter
Zero or more non-"word" characters which balance some sequential
portion of the opening tag delimiter. For example, if the opening
delimiter is "<-(" then any of the following are acceptible closing
delimiters: ")->", "->", or ">". If the closing delimiter is omit‐
ted, the "inverse" of the opening delimiter is used (for example,
")->"),
An optional vertical spacer (zero or more newlines)
One or more whitespace characters up to a mandatory newline. This
vertical space is inserted before and after the complete text.
An optional text indent
Zero or more space of tab characters. Each line of text is indented
by this whitespace (in addition to the tag indent).
For example:
$text = "three lines\nof tagged\ntext";
print tag "A HREF=#nextsection", $text;
prints:
<A HREF=#nextsection>three lines
of tagged
text</A>
whereas:
print tag "[-:GRIN>>>\n", $text;
prints:
[-:GRIN>>>:-]
three lines
of tagged
text
[-:/GRIN>>>:-]
and:
print tag "\n\n <BOLD>\n\n ", $text, "<END BOLD>";
prints:
<BOLD>
three lines
of tagged
text
<END BOLD>
(with the indicated spacing fore and aft).
AUTHOR
Damian Conway (damian@conway.org)
BUGS
The module uses "POSIX::strtod", which may be broken under certain ver‐
sions of Windows. Applying the WINDOWS_PATCH patch to Reform.pm will
replace the POSIX function with a copycat subroutine.
There are undoubtedly serious bugs lurking somewhere in code this funky
:-) Bug reports and other feedback are most welcome.
LICENCE AND COPYRIGHT
Copyright (c) 1997-2007, Damian Conway "<DCONWAY@CPAN.org>". All rights
reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT
WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER
PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND,
EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CON‐
SEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFT‐
WARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED
INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF
THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER
OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
perl v5.8.8 2007-09-30 Text::Reform(3)
