NAME¶
perltidy - a perl script indenter and reformatter
SYNOPSIS¶
perltidy [ options ] file1 file2 file3 ...
(output goes to file1.tdy, file2.tdy, file3.tdy, ...)
perltidy [ options ] file1 -o outfile
perltidy [ options ] file1 -st >outfile
perltidy [ options ] <infile >outfile
DESCRIPTION¶
Perltidy reads a perl script and writes an indented, reformatted script.
Many users will find enough information in "EXAMPLES" to get started.
New users may benefit from the short tutorial which can be found at
http://perltidy.sourceforge.net/tutorial.html
A convenient aid to systematically defining a set of style parameters can be
found at
http://perltidy.sourceforge.net/stylekey.html
Perltidy can produce output on either of two modes, depending on the existence
of an
-html flag. Without this flag, the output is passed through a
formatter. The default formatting tries to follow the recommendations in
perlstyle(1), but it can be controlled in detail with numerous input
parameters, which are described in "FORMATTING OPTIONS".
When the
-html flag is given, the output is passed through an HTML
formatter which is described in "HTML OPTIONS".
EXAMPLES¶
perltidy somefile.pl
This will produce a file
somefile.pl.tdy containing the script
reformatted using the default options, which approximate the style suggested
in
perlstyle(1). Perltidy never changes the input file.
perltidy *.pl
Execute perltidy on all
.pl files in the current directory with the
default options. The output will be in files with an appended
.tdy
extension. For any file with an error, there will be a file with extension
.ERR.
perltidy -b file1.pl file2.pl
Modify
file1.pl and
file2.pl in place, and backup the originals to
file1.pl.bak and
file2.pl.bak. If
file1.pl.bak and/or
file2.pl.bak already exist, they will be overwritten.
perltidy -gnu somefile.pl
Execute perltidy on file
somefile.pl with a style which approximates the
GNU Coding Standards for C programs. The output will be
somefile.pl.tdy.
perltidy -i=3 somefile.pl
Execute perltidy on file
somefile.pl, with 3 columns for each level of
indentation (
-i=3) instead of the default 4 columns. There will not be
any tabs in the reformatted script, except for any which already exist in
comments, pod documents, quotes, and here documents. Output will be
somefile.pl.tdy.
perltidy -i=3 -et=8 somefile.pl
Same as the previous example, except that leading whitespace will be entabbed
with one tab character per 8 spaces.
perltidy -ce -l=72 somefile.pl
Execute perltidy on file
somefile.pl with all defaults except use
"cuddled elses" (
-ce) and a maximum line length of 72
columns (
-l=72) instead of the default 80 columns.
perltidy -g somefile.pl
Execute perltidy on file
somefile.pl and save a log file
somefile.pl.LOG which shows the nesting of braces, parentheses, and
square brackets at the start of every line.
perltidy -html somefile.pl
This will produce a file
somefile.pl.html containing the script with html
markup. The output file will contain an embedded style sheet in the
<HEAD> section which may be edited to change the appearance.
perltidy -html -css=mystyle.css somefile.pl
This will produce a file
somefile.pl.html containing the script with html
markup. This output file will contain a link to a separate style sheet file
mystyle.css. If the file
mystyle.css does not exist, it will be
created. If it exists, it will not be overwritten.
perltidy -html -pre somefile.pl
Write an html snippet with only the PRE section to
somefile.pl.html. This
is useful when code snippets are being formatted for inclusion in a larger web
page. No style sheet will be written in this case.
perltidy -html -ss >mystyle.css
Write a style sheet to
mystyle.css and exit.
perltidy -html -frm mymodule.pm
Write html with a frame holding a table of contents and the source code. The
output files will be
mymodule.pm.html (the frame),
mymodule.pm.toc.html (the table of contents), and
mymodule.pm.src.html (the source code).
OPTIONS - OVERVIEW¶
The entire command line is scanned for options, and they are processed before
any files are processed. As a result, it does not matter whether flags are
before or after any filenames. However, the relative order of parameters is
important, with later parameters overriding the values of earlier parameters.
For each parameter, there is a long name and a short name. The short names are
convenient for keyboard input, while the long names are self-documenting and
therefore useful in scripts. It is customary to use two leading dashes for
long names, but one may be used.
Most parameters which serve as on/off flags can be negated with a leading
"n" (for the short name) or a leading "no" or
"no-" (for the long name). For example, the flag to outdent long
quotes is is
-olq or
--outdent-long-quotes. The flag to skip
this is
-nolq or
--nooutdent-long-quotes or
--no-outdent-long-quotes.
Options may not be bundled together. In other words, options
-q and
-g may NOT be entered as
-qg.
Option names may be terminated early as long as they are uniquely identified.
For example, instead of
--dump-token-types, it would be sufficient to
enter
--dump-tok, or even
--dump-t, to uniquely identify this
command.
I/O control¶
The following parameters concern the files which are read and written.
- -h, --help
- Show summary of usage and exit.
- -o=filename, --outfile=filename
- Name of the output file (only if a single input file is
being processed). If no output file is specified, and output is not
redirected to the standard output (see -st), the output will go to
filename.tdy. [Note: - does not redirect to standard output. Use
-st instead.]
- -st, --standard-output
- Perltidy must be able to operate on an arbitrarily large
number of files in a single run, with each output being directed to a
different output file. Obviously this would conflict with outputting to
the single standard output device, so a special flag, -st, is
required to request outputting to the standard output. For example,
perltidy somefile.pl -st >somefile.new.pl
This option may only be used if there is just a single input file. The
default is -nst or --nostandard-output.
- -se, --standard-error-output
- If perltidy detects an error when processing file
somefile.pl, its default behavior is to write error messages to
file somefile.pl.ERR. Use -se to cause all error messages to
be sent to the standard error output stream instead. This directive may be
negated with -nse. Thus, you may place -se in a
.perltidyrc and override it when desired with -nse on the
command line.
- -oext=ext, --output-file-extension=ext
- Change the extension of the output file to be ext
instead of the default tdy (or html in case the
--html option is used). See "Specifying File
Extensions".
- -opath=path, --output-path=path
- When perltidy creates a filename for an output file, by
default it merely appends an extension to the path and basename of the
input file. This parameter causes the path to be changed to path
instead.
The path should end in a valid path separator character, but perltidy will
try to add one if it is missing.
For example
perltidy somefile.pl -opath=/tmp/
will produce /tmp/somefile.pl.tdy. Otherwise, somefile.pl.tdy
will appear in whatever directory contains somefile.pl.
If the path contains spaces, it should be placed in quotes.
This parameter will be ignored if output is being directed to standard
output, or if it is being specified explicitly with the -o=s
parameter.
- -b, --backup-and-modify-in-place
- Modify the input file or files in-place and save the
original with the extension .bak. Any existing .bak file
will be deleted. See next item for changing the default backup extension.
A -b flag will be ignored if input is from standard input, or if the
-html flag is set.
- -bext=ext, --backup-file-extension=ext
- Change the extension of the backup file to be something
other than the default .bak. See "Specifying File
Extensions".
- -w, --warning-output
- Setting -w causes any non-critical warning messages
to be reported as errors. These include messages about possible pod
problems, possibly bad starting indentation level, and cautions about
indirect object usage. The default, -nw or
--nowarning-output, is not to include these warnings.
- -q, --quiet
- Deactivate error messages and syntax checking (for running
under an editor).
For example, if you use a vi-style editor, such as vim, you may execute
perltidy as a filter from within the editor using something like
:n1,n2!perltidy -q
where "n1,n2" represents the selected text. Without the -q
flag, any error message may mess up your screen, so be prepared to use
your "undo" key.
- -log, --logfile
- Save the .LOG file, which has many useful
diagnostics. Perltidy always creates a .LOG file, but by default it
is deleted unless a program bug is suspected. Setting the -log flag
forces the log file to be saved.
- -g=n, --logfile-gap=n
- Set maximum interval between input code lines in the
logfile. This purpose of this flag is to assist in debugging nesting
errors. The value of "n" is optional. If you set the flag
-g without the value of "n", it will be taken to be 1,
meaning that every line will be written to the log file. This can be
helpful if you are looking for a brace, paren, or bracket nesting error.
Setting -g also causes the logfile to be saved, so it is not
necessary to also include -log.
If no -g flag is given, a value of 50 will be used, meaning that at
least every 50th line will be recorded in the logfile. This helps prevent
excessively long log files.
Setting a negative value of "n" is the same as not setting
-g at all.
- -npro --noprofile
- Ignore any .perltidyrc command file. Normally,
perltidy looks first in your current directory for a .perltidyrc
file of parameters. (The format is described below). If it finds one, it
applies those options to the initial default values, and then it applies
any that have been defined on the command line. If no .perltidyrc
file is found, it looks for one in your home directory.
If you set the -npro flag, perltidy will not look for this file.
- -pro=filename or --profile=filename
- To simplify testing and switching .perltidyrc files, this
command may be used to specify a configuration file which will override
the default name of .perltidyrc. There must not be a space on either side
of the '=' sign. For example, the line
perltidy -pro=testcfg
would cause file testcfg to be used instead of the default
.perltidyrc.
A pathname begins with three dots, e.g. ".../.perltidyrc",
indicates that the file should be searched for starting in the current
directory and working upwards. This makes it easier to have multiple
projects each with their own .perltidyrc in their root directories.
- -opt, --show-options
- Write a list of all options used to the .LOG file.
Please see --dump-options for a simpler way to do this.
- -f, --force-read-binary
- Force perltidy to process binary files. To avoid producing
excessive error messages, perltidy skips files identified by the system as
non-text. However, valid perl scripts containing binary data may sometimes
be identified as non-text, and this flag forces perltidy to process
them.
Basic Options¶
- --notidy
- This flag disables all formatting and causes the input to
be copied unchanged to the output except for possible changes in line
ending characters and any pre- and post-filters. This can be useful in
conjunction with a hierarchical set of .perltidyrc files to avoid
unwanted code tidying. See also "Skipping Selected Sections of
Code" for a way to avoid tidying specific sections of code.
- -l=n, --maximum-line-length=n
- The default maximum line length is n=80 characters.
Perltidy will try to find line break points to keep lines below this
length. However, long quotes and side comments may cause lines to exceed
this length. Setting -l=0 is equivalent to setting -l=(a large
number).
- -i=n, --indent-columns=n
- Use n columns per indentation level (default n=4).
- tabs
- Using tab characters will almost certainly lead to future
portability and maintenance problems, so the default and recommendation is
not to use them. For those who prefer tabs, however, there are two
different options.
Except for possibly introducing tab indentation characters, as outlined
below, perltidy does not introduce any tab characters into your file, and
it removes any tabs from the code (unless requested not to do so with
-fws). If you have any tabs in your comments, quotes, or
here-documents, they will remain.
- -et=n, --entab-leading-whitespace
- This flag causes each n initial space characters to
be replaced by one tab character. Note that the integer n is
completely independent of the integer specified for indentation parameter,
-i=n.
- -t, --tabs
- This flag causes one leading tab character to be inserted
for each level of indentation. Certain other features are incompatible
with this option, and if these options are also given, then a warning
message will be issued and this flag will be unset. One example is the
-lp option.
- -syn, --check-syntax
- This flag causes perltidy to run "perl -c -T" to
check syntax of input and output. (To change the flags passed to perl, see
the next item, -pscf). The results are written to the .LOG
file, which will be saved if an error is detected in the output script.
The output script is not checked if the input script has a syntax error.
Perltidy does its own checking, but this option employs perl to get a
"second opinion".
If perl reports errors in the input file, they will not be reported in the
error output unless the --warning-output flag is given.
The default is not to do this type of syntax checking (although
perltidy will still do as much self-checking as possible). The reason is
that it causes all code in BEGIN blocks to be executed, for all modules
being used, and this opens the door to security issues and infinite loops
when running perltidy.
- -pscf=s, -perl-syntax-check-flags=s
- When perl is invoked to check syntax, the normal flags are
"-c -T". In addition, if the -x flag is given to
perltidy, then perl will also be passed a -x flag. It should not
normally be necessary to change these flags, but it can be done with the
-pscf=s flag. For example, if the taint flag, "-T", is
not wanted, the flag could be set to be just -pscf=-c.
Perltidy will pass your string to perl with the exception that it will add a
-c and -x if appropriate. The .LOG file will show
exactly what flags were passed to perl.
- -io, --indent-only
- This flag is used to deactivate all formatting and line
break changes within non-blank lines of code. When it is in effect, the
only change to the script will be to the indentation and blank lines. And
any flags controlling whitespace and newlines will be ignored. You might
want to use this if you are perfectly happy with your whitespace and line
breaks, and merely want perltidy to handle the indentation. (This also
speeds up perltidy by well over a factor of two, so it might be useful
when perltidy is merely being used to help find a brace error in a large
script).
Setting this flag is equivalent to setting --freeze-newlines and
--freeze-whitespace.
If you also want to keep your existing blank lines exactly as they are, you
can add --freeze-blank-lines.
- -ole=s, --output-line-ending=s
- where s="win", "dos", "unix",
or "mac". This flag tells perltidy to output line endings for a
specific system. Normally, perltidy writes files with the line separator
character of the host system. The "win" and "dos"
flags have an identical result.
- -ple, --preserve-line-endings
- This flag tells perltidy to write its output files with the
same line endings as the input file, if possible. It should work for
dos, unix, and mac line endings. It will only work if
perltidy input comes from a filename (rather than stdin, for example). If
perltidy has trouble determining the input file line ending, it will
revert to the default behavior of using the line ending of the host
system.
- -it=n, --iterations=n
- This flag causes perltidy to do n complete
iterations. The reason for this flag is that code beautification is a
somewhat iterative process and in some cases the output from perltidy can
be different if it is applied a second time. For most purposes the default
of n=1 should be satisfactory. However n=2 can be useful
when a major style change is being made, or when code is being beautified
on check-in to a source code control system. The run time will be
approximately proportional to n, and it should seldom be necessary
to use a value greater than n=2. This flag has no effect when
perltidy is used to generate html.
Code Indentation Control¶
- -ci=n, --continuation-indentation=n
- Continuation indentation is extra indentation spaces
applied when a long line is broken. The default is n=2, illustrated here:
my $level = # -ci=2
( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
The same example, with n=0, is a little harder to read:
my $level = # -ci=0
( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
The value given to -ci is also used by some commands when a small
space is required. Examples are commands for outdenting labels,
-ola, and control keywords, -okw.
When default values are not used, it is suggested that the value n
given with -ci=n be no more than about one-half of the number of
spaces assigned to a full indentation level on the -i=n
command.
- -sil=n --starting-indentation-level=n
- By default, perltidy examines the input file and tries to
determine the starting indentation level. While it is often zero, it may
not be zero for a code snippet being sent from an editing session. If the
default method does not work correctly, or you want to change the starting
level, use -sil=n, to force the starting level to be n.
- List indentation using -lp,
--line-up-parentheses
- By default, perltidy indents lists with 4 spaces, or
whatever value is specified with -i=n. Here is a small list
formatted in this way:
# perltidy (default)
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
Use the -lp flag to add extra indentation to cause the data to begin
past the opening parentheses of a sub call or list, or opening square
bracket of an anonymous array, or opening curly brace of an anonymous
hash. With this option, the above list would become:
# perltidy -lp
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
If the available line length (see -l=n ) does not permit this much
space, perltidy will use less. For alternate placement of the closing
paren, see the next section.
This option has no effect on code BLOCKS, such as if/then/else blocks, which
always use whatever is specified with -i=n. Also, the existence of
line breaks and/or block comments between the opening and closing parens
may cause perltidy to temporarily revert to its default method.
Note: The -lp option may not be used together with the -t tabs
option. It may, however, be used with the -et=n tab method.
In addition, any parameter which significantly restricts the ability of
perltidy to choose newlines will conflict with -lp and will cause
-lp to be deactivated. These include -io, -fnl,
-nanl, and -ndnl. The reason is that the -lp
indentation style can require the careful coordination of an arbitrary
number of break points in hierarchical lists, and these flags may prevent
that.
- -cti=n, --closing-token-indentation
- The -cti=n flag controls the indentation of a line
beginning with a ")", "]", or a non-block
"}". Such a line receives:
-cti = 0 no extra indentation (default)
-cti = 1 extra indentation such that the closing token
aligns with its opening token.
-cti = 2 one extra indentation level if the line looks like:
); or ]; or };
-cti = 3 one extra indentation level always
The flags -cti=1 and -cti=2 work well with the -lp flag
(previous section).
# perltidy -lp -cti=1
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
# perltidy -lp -cti=2
@month_of_year = (
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
);
These flags are merely hints to the formatter and they may not always be
followed. In particular, if -lp is not being used, the indentation for
cti=1 is constrained to be no more than one indentation level.
If desired, this control can be applied independently to each of the closing
container token types. In fact, -cti=n is merely an abbreviation
for -cpi=n -csbi=n -cbi=n, where: -cpi or
--closing-paren-indentation controls )'s, -csbi or
--closing-square-bracket-indentation controls ]'s,
-cbi or --closing-brace-indentation controls non-block
}'s.
- -icp, --indent-closing-paren
- The -icp flag is equivalent to -cti=2,
described in the previous section. The -nicp flag is equivalent
-cti=0. They are included for backwards compatability.
- -icb, --indent-closing-brace
- The -icb option gives one extra level of indentation
to a brace which terminates a code block . For example,
if ($task) {
yyy();
} # -icb
else {
zzz();
}
The default is not to do this, indicated by -nicb.
- -olq, --outdent-long-quotes
- When -olq is set, lines which is a quoted string
longer than the value maximum-line-length will have their
indentation removed to make them more readable. This is the default. To
prevent such out-denting, use -nolq or
--nooutdent-long-lines.
- -oll, --outdent-long-lines
- This command is equivalent to --outdent-long-quotes
and --outdent-long-comments, and it is included for compatibility
with previous versions of perltidy. The negation of this also works,
-noll or --nooutdent-long-lines, and is equivalent to
setting -nolq and -nolc.
- Outdenting Labels: -ola,
--outdent-labels
- This command will cause labels to be outdented by 2 spaces
(or whatever -ci has been set to), if possible. This is the
default. For example:
my $i;
LOOP: while ( $i = <FOTOS> ) {
chomp($i);
next unless $i;
fixit($i);
}
Use -nola to not outdent labels.
- Outdenting Keywords
- -okw, --outdent-keywords
- The command -okw will will cause certain leading
control keywords to be outdented by 2 spaces (or whatever -ci has
been set to), if possible. By default, these keywords are
"redo", "next", "last", "goto",
and "return". The intention is to make these control keywords
easier to see. To change this list of keywords being outdented, see the
next section.
For example, using "perltidy -okw" on the previous example gives:
my $i;
LOOP: while ( $i = <FOTOS> ) {
chomp($i);
next unless $i;
fixit($i);
}
The default is not to do this.
- Specifying Outdented Keywords: -okwl=string,
--outdent-keyword-list=string
- This command can be used to change the keywords which are
outdented with the -okw command. The parameter string is a
required list of perl keywords, which should be placed in quotes if there
are more than one. By itself, it does not cause any outdenting to occur,
so the -okw command is still required.
For example, the commands "-okwl="next last redo goto"
-okw" will cause those four keywords to be outdented. It is probably
simplest to place any -okwl command in a .perltidyrc
file.
Whitespace Control¶
Whitespace refers to the blank space between variables, operators, and other
code tokens.
- -fws, --freeze-whitespace
- This flag causes your original whitespace to remain
unchanged, and causes the rest of the whitespace commands in this section,
the Code Indentation section, and the Comment Control section to be
ignored.
- Tightness of curly braces, parentheses, and square
brackets.
- Here the term "tightness" will mean the closeness
with which pairs of enclosing tokens, such as parentheses, contain the
quantities within. A numerical value of 0, 1, or 2 defines the tightness,
with 0 being least tight and 2 being most tight. Spaces within containers
are always symmetric, so if there is a space after a "(" then
there will be a space before the corresponding ")".
The -pt=n or --paren-tightness=n parameter controls the space
within parens. The example below shows the effect of the three possible
values, 0, 1, and 2:
if ( ( my $len_tab = length( $tabstr ) ) > 0 ) { # -pt=0
if ( ( my $len_tab = length($tabstr) ) > 0 ) { # -pt=1 (default)
if ((my $len_tab = length($tabstr)) > 0) { # -pt=2
When n is 0, there is always a space to the right of a '(' and to the left
of a ')'. For n=2 there is never a space. For n=1, the default, there is a
space unless the quantity within the parens is a single token, such as an
identifier or quoted string.
Likewise, the parameter -sbt=n or --square-bracket-tightness=n
controls the space within square brackets, as illustrated below.
$width = $col[ $j + $k ] - $col[ $j ]; # -sbt=0
$width = $col[ $j + $k ] - $col[$j]; # -sbt=1 (default)
$width = $col[$j + $k] - $col[$j]; # -sbt=2
Curly braces which do not contain code blocks are controlled by the
parameter -bt=n or --brace-tightness=n.
$obj->{ $parsed_sql->{ 'table' }[0] }; # -bt=0
$obj->{ $parsed_sql->{'table'}[0] }; # -bt=1 (default)
$obj->{$parsed_sql->{'table'}[0]}; # -bt=2
And finally, curly braces which contain blocks of code are controlled by the
parameter -bbt=n or --block-brace-tightness=n as illustrated
in the example below.
%bf = map { $_ => -M $_ } grep { /\.deb$/ } dirents '.'; # -bbt=0 (default)
%bf = map { $_ => -M $_ } grep {/\.deb$/} dirents '.'; # -bbt=1
%bf = map {$_ => -M $_} grep {/\.deb$/} dirents '.'; # -bbt=2
- -sts, --space-terminal-semicolon
- Some programmers prefer a space before all terminal
semicolons. The default is for no such space, and is indicated with
-nsts or --nospace-terminal-semicolon.
$i = 1 ; # -sts
$i = 1; # -nsts (default)
- -sfs, --space-for-semicolon
- Semicolons within for loops may sometimes be hard to
see, particularly when commas are also present. This option places spaces
on both sides of these special semicolons, and is the default. Use
-nsfs or --nospace-for-semicolon to deactivate it.
for ( @a = @$ap, $u = shift @a ; @a ; $u = $v ) { # -sfs (default)
for ( @a = @$ap, $u = shift @a; @a; $u = $v ) { # -nsfs
- -asc, --add-semicolons
- Setting -asc allows perltidy to add any missing
optional semicolon at the end of a line which is followed by a closing
curly brace on the next line. This is the default, and may be deactivated
with -nasc or --noadd-semicolons.
- -dsm, --delete-semicolons
- Setting -dsm allows perltidy to delete extra
semicolons which are simply empty statements. This is the default, and may
be deactivated with -ndsm or --nodelete-semicolons. (Such
semicolons are not deleted, however, if they would promote a side comment
to a block comment).
- -aws, --add-whitespace
- Setting this option allows perltidy to add certain
whitespace improve code readability. This is the default. If you do not
want any whitespace added, but are willing to have some whitespace
deleted, use -naws. (Use -fws to leave whitespace completely
unchanged).
- -dws, --delete-old-whitespace
- Setting this option allows perltidy to remove some old
whitespace between characters, if necessary. This is the default. If you
do not want any old whitespace removed, use -ndws or
--nodelete-old-whitespace.
- Detailed whitespace controls around tokens
- For those who want more detailed control over the
whitespace around tokens, there are four parameters which can directly
modify the default whitespace rules built into perltidy for any token.
They are:
-wls=s or --want-left-space=s,
-nwls=s or --nowant-left-space=s,
-wrs=s or --want-right-space=s,
-nwrs=s or --nowant-right-space=s.
These parameters are each followed by a quoted string, s, containing
a list of token types. No more than one of each of these parameters should
be specified, because repeating a command-line parameter always overwrites
the previous one before perltidy ever sees it.
To illustrate how these are used, suppose it is desired that there be no
space on either side of the token types = + - / *. The following
two parameters would specify this desire:
-nwls="= + - / *" -nwrs="= + - / *"
(Note that the token types are in quotes, and that they are separated by
spaces). With these modified whitespace rules, the following line of math:
$root = -$b + sqrt( $b * $b - 4. * $a * $c ) / ( 2. * $a );
becomes this:
$root=-$b+sqrt( $b*$b-4.*$a*$c )/( 2.*$a );
These parameters should be considered to be hints to perltidy rather than
fixed rules, because perltidy must try to resolve conflicts that arise
between them and all of the other rules that it uses. One conflict that
can arise is if, between two tokens, the left token wants a space and the
right one doesn't. In this case, the token not wanting a space takes
priority.
It is necessary to have a list of all token types in order to create this
type of input. Such a list can be obtained by the command
--dump-token-types. Also try the -D flag on a short snippet
of code and look at the .DEBUG file to see the tokenization.
WARNING Be sure to put these tokens in quotes to avoid having them
misinterpreted by your command shell.
- Space between specific keywords and opening paren
- When an opening paren follows a Perl keyword, no space is
introduced after the keyword, unless it is (by default) one of these:
my local our and or eq ne if else elsif until unless
while for foreach return switch case given when
These defaults can be modified with two commands:
-sak=s or --space-after-keyword=s adds keywords.
-nsak=s or --nospace-after-keyword=s removes keywords.
where s is a list of keywords (in quotes if necessary). For example,
my ( $a, $b, $c ) = @_; # default
my( $a, $b, $c ) = @_; # -nsak="my local our"
To put a space after all keywords, see the next item.
- Space between all keywords and opening parens
- When an opening paren follows a function or keyword, no
space is introduced after the keyword except for the keywords noted in the
previous item. To always put a space between a function or keyword and its
opening paren, use the command:
-skp or --space-keyword-paren
You will probably also want to use the flag -sfp (next item)
too.
- Space between all function names and opening parens
- When an opening paren follows a function the default is not
to introduce a space. To cause a space to be introduced use:
-sfp or --space-function-paren
myfunc( $a, $b, $c ); # default
myfunc ( $a, $b, $c ); # -sfp
You will probably also want to use the flag -skp (previous item)
too.
- Trimming whitespace around "qw" quotes
- -tqw or --trim-qw provide the default
behavior of trimming spaces around multi-line "qw" quotes and
indenting them appropriately.
-ntqw or --notrim-qw cause leading and trailing whitespace
around multi-line "qw" quotes to be left unchanged. This option
will not normally be necessary, but was added for testing purposes,
because in some versions of perl, trimming "qw" quotes changes
the syntax tree.
Perltidy has a number of ways to control the appearance of both block comments
and side comments. The term
block comment here refers to a full-line
comment, whereas
side comment will refer to a comment which appears on
a line to the right of some code.
- -ibc, --indent-block-comments
- Block comments normally look best when they are indented to
the same level as the code which follows them. This is the default
behavior, but you may use -nibc to keep block comments
left-justified. Here is an example:
# this comment is indented (-ibc, default)
if ($task) { yyy(); }
The alternative is -nibc:
# this comment is not indented (-nibc)
if ($task) { yyy(); }
See also the next item, -isbc, as well as -sbc, for other ways
to have some indented and some outdented block comments.
- -isbc, --indent-spaced-block-comments
- If there is no leading space on the line, then the comment
will not be indented, and otherwise it may be.
If both -ibc and -isbc are set, then -isbc takes
priority.
- -olc, --outdent-long-comments
- When -olc is set, lines which are full-line (block)
comments longer than the value maximum-line-length will have their
indentation removed. This is the default; use -nolc to prevent
outdenting.
- -msc=n, --minimum-space-to-comment=n
- Side comments look best when lined up several spaces to the
right of code. Perltidy will try to keep comments at least n spaces to the
right. The default is n=4 spaces.
- -fpsc=n, --fixed-position-side-comment=n
- This parameter tells perltidy to line up side comments in
column number n whenever possible. The default, n=0, is not do do
this.
- -hsc, --hanging-side-comments
- By default, perltidy tries to identify and align
"hanging side comments", which are something like this:
my $IGNORE = 0; # This is a side comment
# This is a hanging side comment
# And so is this
A comment is considered to be a hanging side comment if (1) it immediately
follows a line with a side comment, or another hanging side comment, and
(2) there is some leading whitespace on the line. To deactivate this
feature, use -nhsc or --nohanging-side-comments. If block
comments are preceded by a blank line, or have no leading whitespace, they
will not be mistaken as hanging side comments.
- Closing Side Comments
- A closing side comment is a special comment which perltidy
can automatically create and place after the closing brace of a code
block. They can be useful for code maintenance and debugging. The command
-csc (or --closing-side-comments) adds or updates closing
side comments. For example, here is a small code snippet
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
}
And here is the result of processing with "perltidy -csc":
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
} ## end sub message
A closing side comment was added for "sub message" in this case,
but not for the "if" and "else" blocks, because they
were below the 6 line cutoff limit for adding closing side comments. This
limit may be changed with the -csci command, described below.
The command -dcsc (or --delete-closing-side-comments) reverses
this process and removes these comments.
Several commands are available to modify the behavior of these two basic
commands, -csc and -dcsc:
- -csci=n, or
--closing-side-comment-interval=n
- where "n" is the minimum number of lines that a
block must have in order for a closing side comment to be added. The
default value is "n=6". To illustrate:
# perltidy -csci=2 -csc
sub message {
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
} ## end if ( !defined( $_[0] ))
else {
print( $_[0], "\n" );
} ## end else [ if ( !defined( $_[0] ))
} ## end sub message
Now the "if" and "else" blocks are commented. However,
now this has become very cluttered.
- -cscp=string, or
--closing-side-comment-prefix=string
- where string is the prefix used before the name of the
block type. The default prefix, shown above, is "## end". This
string will be added to closing side comments, and it will also be used to
recognize them in order to update, delete, and format them. Any comment
identified as a closing side comment will be placed just a single space to
the right of its closing brace.
- -cscl=string, or
--closing-side-comment-list-string
- where "string" is a list of block types to be
tagged with closing side comments. By default, all code block types
preceded by a keyword or label (such as "if", "sub",
and so on) will be tagged. The -cscl command changes the default
list to be any selected block types; see "Specifying Block
Types". For example, the following command requests that only
"sub"'s, labels, "BEGIN", and "END" blocks
be affected by any -csc or -dcsc operation:
-cscl="sub : BEGIN END"
- -csct=n, or
--closing-side-comment-maximum-text=n
- The text appended to certain block types, such as an
"if" block, is whatever lies between the keyword introducing the
block, such as "if", and the opening brace. Since this might be
too much text for a side comment, there needs to be a limit, and that is
the purpose of this parameter. The default value is "n=20",
meaning that no additional tokens will be appended to this text after its
length reaches 20 characters. Omitted text is indicated with
"...". (Tokens, including sub names, are never truncated,
however, so actual lengths may exceed this). To illustrate, in the above
example, the appended text of the first block is " ( !defined( $_[0]
)...". The existing limit of "n=20" caused this text to be
truncated, as indicated by the "...". See the next flag for
additional control of the abbreviated text.
- -cscb, or
--closing-side-comments-balanced
- As discussed in the previous item, when the
closing-side-comment-maximum-text limit is exceeded the comment text must
be truncated. Older versions of perltidy terminated with three dots, and
this can still be achieved with -ncscb:
perltidy -csc -ncscb
} ## end foreach my $foo (sort { $b cmp $a ...
However this causes a problem with editors editors which cannot recognize
comments or are not configured to do so because they cannot
"bounce" around in the text correctly. The -cscb flag has
been added to help them by appending appropriate balancing structure:
perltidy -csc -cscb
} ## end foreach my $foo (sort { $b cmp $a ... })
The default is -cscb.
- -csce=n, or
--closing-side-comment-else-flag=n
- The default, n=0, places the text of the opening
"if" statement after any terminal "else".
If n=2 is used, then each "elsif" is also given the text of
the opening "if" statement. Also, an "else" will
include the text of a preceding "elsif" statement. Note that
this may result some long closing side comments.
If n=1 is used, the results will be the same as n=2 whenever
the resulting line length is less than the maximum allowed. =item
-cscb, or --closing-side-comments-balanced
When using closing-side-comments, and the closing-side-comment-maximum-text
limit is exceeded, then the comment text must be abbreviated. It is
terminated with three dots if the -cscb flag is negated:
perltidy -csc -ncscb
} ## end foreach my $foo (sort { $b cmp $a ...
This causes a problem with older editors which do not recognize comments
because they cannot "bounce" around in the text correctly. The
-cscb flag tries to help them by appending appropriate terminal
balancing structures:
perltidy -csc -cscb
} ## end foreach my $foo (sort { $b cmp $a ... })
The default is -cscb.
- -cscw, or
--closing-side-comment-warnings
- This parameter is intended to help make the initial
transition to the use of closing side comments. It causes two things to
happen if a closing side comment replaces an existing, different closing
side comment: first, an error message will be issued, and second, the
original side comment will be placed alone on a new specially marked
comment line for later attention.
The intent is to avoid clobbering existing hand-written side comments which
happen to match the pattern of closing side comments. This flag should
only be needed on the first run with -csc.
Important Notes on Closing Side Comments:
- •
- Closing side comments are only placed on lines terminated
with a closing brace. Certain closing styles, such as the use of cuddled
elses ( -ce), preclude the generation of some closing side
comments.
- •
- Please note that adding or deleting of closing side
comments takes place only through the commands -csc or
-dcsc. The other commands, if used, merely modify the behavior of
these two commands.
- •
- It is recommended that the -cscw flag be used along
with -csc on the first use of perltidy on a given file. This will
prevent loss of any existing side comment data which happens to have the
csc prefix.
- •
- Once you use -csc, you should continue to use it so
that any closing side comments remain correct as code changes. Otherwise,
these comments will become incorrect as the code is updated.
- •
- If you edit the closing side comments generated by
perltidy, you must also change the prefix to be different from the closing
side comment prefix. Otherwise, your edits will be lost when you rerun
perltidy with -csc. For example, you could simply change "##
end" to be "## End", since the test is case sensitive. You
may also want to use the -ssc flag to keep these modified closing
side comments spaced the same as actual closing side comments.
- •
- Temporarily generating closing side comments is a useful
technique for exploring and/or debugging a perl script, especially one
written by someone else. You can always remove them with
-dcsc.
- Static Block Comments
- Static block comments are block comments with a special
leading pattern, "##" by default, which will be treated slightly
differently from other block comments. They effectively behave as if they
had glue along their left and top edges, because they stick to the left
edge and previous line when there is no blank spaces in those places. This
option is particularly useful for controlling how commented code is
displayed.
- -sbc, --static-block-comments
- When -sbc is used, a block comment with a special
leading pattern, "##" by default, will be treated specially.
Comments so identified are treated as follows:
- •
- If there is no leading space on the line, then the comment
will not be indented, and otherwise it may be,
- •
- no new blank line will be inserted before such a comment,
and
- •
- such a comment will never become a hanging side
comment.
For example, assuming @month_of_year is left-adjusted:
@month_of_year = ( # -sbc (default)
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
## 'Dec', 'Nov'
'Nov', 'Dec');
Without this convention, the above code would become
@month_of_year = ( # -nsbc
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
## 'Dec', 'Nov'
'Nov', 'Dec'
);
which is not as clear. The default is to use
-sbc. This may be
deactivated with
-nsbc.
- -sbcp=string,
--static-block-comment-prefix=string
- This parameter defines the prefix used to identify static
block comments when the -sbc parameter is set. The default prefix
is "##", corresponding to "-sbcp=##". The prefix is
actually part of a perl pattern used to match lines and it must either
begin with "#" or "^#". In the first case a prefix
^\s* will be added to match any leading whitespace, while in the second
case the pattern will match only comments with no leading whitespace. For
example, to identify all comments as static block comments, one would use
"-sbcp=#". To identify all left-adjusted comments as static
block comments, use "-sbcp='^#'".
Please note that -sbcp merely defines the pattern used to identify
static block comments; it will not be used unless the switch -sbc
is set. Also, please be aware that since this string is used in a perl
regular expression which identifies these comments, it must enable a valid
regular expression to be formed.
A pattern which can be useful is:
-sbcp=^#{2,}[^\s#]
This pattern requires a static block comment to have at least one character
which is neither a # nor a space. It allows a line containing only '#'
characters to be rejected as a static block comment. Such lines are often
used at the start and end of header information in subroutines and should
not be separated from the intervening comments, which typically begin with
just a single '#'.
- -osbc, --outdent-static-block-comments
- The command -osbc will will cause static block
comments to be outdented by 2 spaces (or whatever -ci=n has been
set to), if possible.
- Static Side Comments
- Static side comments are side comments with a special
leading pattern. This option can be useful for controlling how commented
code is displayed when it is a side comment.
- -ssc, --static-side-comments
- When -ssc is used, a side comment with a static
leading pattern, which is "##" by default, will be be spaced
only a single space from previous character, and it will not be vertically
aligned with other side comments.
The default is -nssc.
- -sscp=string,
--static-side-comment-prefix=string
- This parameter defines the prefix used to identify static
side comments when the -ssc parameter is set. The default prefix is
"##", corresponding to "-sscp=##".
Please note that -sscp merely defines the pattern used to identify
static side comments; it will not be used unless the switch -ssc is
set. Also, note that this string is used in a perl regular expression
which identifies these comments, so it must enable a valid regular
expression to be formed.
Skipping Selected Sections of Code¶
Selected lines of code may be passed verbatim to the output without any
formatting. This feature is enabled by default but can be disabled with the
--noformat-skipping or
-nfs flag. It should be used sparingly to
avoid littering code with markers, but it might be helpful for working around
occasional problems. For example it might be useful for keeping the
indentation of old commented code unchanged, keeping indentation of long
blocks of aligned comments unchanged, keeping certain list formatting
unchanged, or working around a glitch in perltidy.
- -fs, --format-skipping
- This flag, which is enabled by default, causes any code
between special beginning and ending comment markers to be passed to the
output without formatting. The default beginning marker is #<<<
and the default ending marker is #>>> but they may be changed
(see next items below). Additional text may appear on these special
comment lines provided that it is separated from the marker by at least
one space. For example
#<<< do not let perltidy touch this
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
#>>>
The comment markers may be placed at any location that a block comment may
appear. If they do not appear to be working, use the -log flag and examine
the .LOG file. Use -nfs to disable this feature.
- -fsb=string,
--format-skipping-begin=string
- The -fsb=string parameter may be used to change the
beginning marker for format skipping. The default is equivalent to
-fsb='#<<<'. The string that you enter must begin with a # and
should be in quotes as necessary to get past the command shell of your
system. It is actually the leading text of a pattern that is constructed
by appending a '\s', so you must also include backslashes for characters
to be taken literally rather than as patterns.
Some examples show how example strings become patterns:
-fsb='#\{\{\{' becomes /^#\{\{\{\s/ which matches #{{{ but not #{{{{
-fsb='#\*\*' becomes /^#\*\*\s/ which matches #** but not #***
-fsb='#\*{2,}' becomes /^#\*{2,}\s/ which matches #** and #*****
- -fse=string,
--format-skipping-end=string
- The -fsb=string is the corresponding parameter used
to change the ending marker for format skipping. The default is equivalent
to -fse='#<<<'.
Line Break Control¶
The parameters in this section control breaks after non-blank lines of code.
Blank lines are controlled separately by parameters in the section "Blank
Line Control".
- -fnl, --freeze-newlines
- If you do not want any changes to the line breaks within
lines of code in your script, set -fnl, and they will remain fixed,
and the rest of the commands in this section and sections
"Controlling List Formatting", "Retaining or Ignoring
Existing Line Breaks". You may want to use -noll with this.
Note: If you also want to keep your blank lines exactly as they are, you can
use the -fbl flag which is described in the section "Blank
Line Control".
- -ce, --cuddled-else
- Enable the "cuddled else" style, in which
"else" and "elsif" are follow immediately after the
curly brace closing the previous block. The default is not to use cuddled
elses, and is indicated with the flag -nce or
--nocuddled-else. Here is a comparison of the alternatives:
if ($task) {
yyy();
} else { # -ce
zzz();
}
if ($task) {
yyy();
}
else { # -nce (default)
zzz();
}
- -bl, --opening-brace-on-new-line
- Use the flag -bl to place the opening brace on a new
line:
if ( $input_file eq '-' ) # -bl
{
important_function();
}
This flag applies to all structural blocks, including named sub's (unless
the -sbl flag is set -- see next item).
The default style, -nbl, places an opening brace on the same line as
the keyword introducing it. For example,
if ( $input_file eq '-' ) { # -nbl (default)
- -sbl, --opening-sub-brace-on-new-line
- The flag -sbl can be used to override the value of
-bl for the opening braces of named sub's. For example,
perltidy -sbl
produces this result:
sub message
{
if (!defined($_[0])) {
print("Hello, World\n");
}
else {
print($_[0], "\n");
}
}
This flag is negated with -nsbl. If -sbl is not specified, the
value of -bl is used.
- -asbl,
--opening-anonymous-sub-brace-on-new-line
- The flag -asbl is like the -sbl flag except
that it applies to anonymous sub's instead of named subs. For example
perltidy -asbl
produces this result:
$a = sub
{
if ( !defined( $_[0] ) ) {
print("Hello, World\n");
}
else {
print( $_[0], "\n" );
}
};
This flag is negated with -nasbl, and the default is
-nasbl.
- -bli, --brace-left-and-indent
- The flag -bli is the same as -bl but in
addition it causes one unit of continuation indentation ( see -ci )
to be placed before an opening and closing block braces.
For example,
if ( $input_file eq '-' ) # -bli
{
important_function();
}
By default, this extra indentation occurs for blocks of type: if,
elsif, else, unless, for, foreach,
sub, while, until, and also with a preceding label.
The next item shows how to change this.
- -blil=s, --brace-left-and-indent-list=s
- Use this parameter to change the types of block braces for
which the -bli flag applies; see "Specifying Block
Types". For example, -blil='if elsif else' would apply it to
only "if/elsif/else" blocks.
- -bar, --opening-brace-always-on-right
- The default style, -nbl places the opening code
block brace on a new line if it does not fit on the same line as the
opening keyword, like this:
if ( $bigwasteofspace1 && $bigwasteofspace2
|| $bigwasteofspace3 && $bigwasteofspace4 )
{
big_waste_of_time();
}
To force the opening brace to always be on the right, use the -bar
flag. In this case, the above example becomes
if ( $bigwasteofspace1 && $bigwasteofspace2
|| $bigwasteofspace3 && $bigwasteofspace4 ) {
big_waste_of_time();
}
A conflict occurs if both -bl and -bar are specified.
- -otr, --opening-token-right and related
flags
- The -otr flag is a hint that perltidy should not
place a break between a comma and an opening token. For example:
# default formatting
push @{ $self->{$module}{$key} },
{
accno => $ref->{accno},
description => $ref->{description}
};
# perltidy -otr
push @{ $self->{$module}{$key} }, {
accno => $ref->{accno},
description => $ref->{description}
};
The flag -otr is actually a synonym for three other flags which can
be used to control parens, hash braces, and square brackets separately if
desired:
-opr or --opening-paren-right
-ohbr or --opening-hash-brace-right
-osbr or --opening-square-bracket-right
- Vertical tightness of non-block curly braces, parentheses,
and square brackets.
- These parameters control what shall be called vertical
tightness. Here are the main points:
- •
- Opening tokens (except for block braces) are controlled by
-vt=n, or --vertical-tightness=n, where
-vt=0 always break a line after opening token (default).
-vt=1 do not break unless this would produce more than one
step in indentation in a line.
-vt=2 never break a line after opening token
- •
- You must also use the -lp flag when you use the
-vt flag; the reason is explained below.
- •
- Closing tokens (except for block braces) are controlled by
-vtc=n, or --vertical-tightness-closing=n, where
-vtc=0 always break a line before a closing token (default),
-vtc=1 do not break before a closing token which is followed
by a semicolon or another closing token, and is not in
a list environment.
-vtc=2 never break before a closing token.
The rules for -vtc=1 are designed to maintain a reasonable balance
between tightness and readability in complex lists.
- •
- Different controls may be applied to to different token
types, and it is also possible to control block braces; see below.
- •
- Finally, please note that these vertical tightness flags
are merely hints to the formatter, and it cannot always follow them.
Things which make it difficult or impossible include comments, blank
lines, blocks of code within a list, and possibly the lack of the
-lp parameter. Also, these flags may be ignored for very small
lists (2 or 3 lines in length).
Here are some examples:
# perltidy -lp -vt=0 -vtc=0
%romanNumerals = (
one => 'I',
two => 'II',
three => 'III',
four => 'IV',
);
# perltidy -lp -vt=1 -vtc=0
%romanNumerals = ( one => 'I',
two => 'II',
three => 'III',
four => 'IV',
);
# perltidy -lp -vt=1 -vtc=1
%romanNumerals = ( one => 'I',
two => 'II',
three => 'III',
four => 'IV', );
The difference between
-vt=1 and
-vt=2 is shown here:
# perltidy -lp -vt=1
$init->add(
mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] )
)
);
# perltidy -lp -vt=2
$init->add( mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] )
)
);
With
-vt=1, the line ending in "add(" does not combine with the
next line because the next line is not balanced. This can help with
readability, but
-vt=2 can be used to ignore this rule.
The tightest, and least readable, code is produced with both "-vt=2"
and "-vtc=2":
# perltidy -lp -vt=2 -vtc=2
$init->add( mysprintf( "(void)find_threadsv(%s);",
cstring( $threadsv_names[ $op->targ ] ) ) );
Notice how the code in all of these examples collapses vertically as
-vt
increases, but the indentation remains unchanged. This is because perltidy
implements the
-vt parameter by first formatting as if
-vt=0,
and then simply overwriting one output line on top of the next, if possible,
to achieve the desired vertical tightness. The
-lp indentation style
has been designed to allow this vertical collapse to occur, which is why it is
required for the
-vt parameter.
The
-vt=n and
-vtc=n parameters apply to each type of container
token. If desired, vertical tightness controls can be applied independently to
each of the closing container token types.
The parameters for controlling parentheses are
-pvt=n or
--paren-vertical-tightness=n, and
-pcvt=n or
--paren-vertical-tightness-closing=n.
Likewise, the parameters for square brackets are
-sbvt=n or
--square-bracket-vertical-tightness=n, and
-sbcvt=n or
--square-bracket-vertical-tightness-closing=n.
Finally, the parameters for controlling non-code block braces are
-bvt=n
or
--brace-vertical-tightness=n, and
-bcvt=n or
--brace-vertical-tightness-closing=n.
In fact, the parameter
-vt=n is actually just an abbreviation for
-pvt=n -bvt=n sbvt=n, and likewise
-vtc=n is an abbreviation for
-pvtc=n -bvtc=n sbvtc=n.
- -bbvt=n or
--block-brace-vertical-tightness=n
- The -bbvt=n flag is just like the -vt=n flag
but applies to opening code block braces.
-bbvt=0 break after opening block brace (default).
-bbvt=1 do not break unless this would produce more than one
step in indentation in a line.
-bbvt=2 do not break after opening block brace.
It is necessary to also use either -bl or -bli for this to
work, because, as with other vertical tightness controls, it is
implemented by simply overwriting a line ending with an opening block
brace with the subsequent line. For example:
# perltidy -bli -bbvt=0
if ( open( FILE, "< $File" ) )
{
while ( $File = <FILE> )
{
$In .= $File;
$count++;
}
close(FILE);
}
# perltidy -bli -bbvt=1
if ( open( FILE, "< $File" ) )
{ while ( $File = <FILE> )
{ $In .= $File;
$count++;
}
close(FILE);
}
By default this applies to blocks associated with keywords if,
elsif, else, unless, for, foreach,
sub, while, until, and also with a preceding label.
This can be changed with the parameter -bbvtl=string, or
--block-brace-vertical-tightness-list=string, where string
is a space-separated list of block types. For more information on the
possible values of this string, see "Specifying Block Types"
For example, if we want to just apply this style to "if",
"elsif", and "else" blocks, we could use
"perltidy -bli -bbvt=1 -bbvtl='if elsif else'".
There is no vertical tightness control for closing block braces; with the
exception of one-line blocks, they will normally remain on a separate
line.
- -sot, --stack-opening-tokens and related
flags
- The -sot flag tells perltidy to "stack"
opening tokens when possible to avoid lines with isolated opening tokens.
For example:
# default
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
# -sot
$opt_c = Text::CSV_XS->new( {
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
For detailed control of individual closing tokens the following controls can
be used:
-sop or --stack-opening-paren
-sohb or --stack-opening-hash-brace
-sosb or --stack-opening-square-bracket
The flag -sot is a synonym for -sop -sohb -sosb.
- -sct, --stack-closing-tokens and related
flags
- The -sct flag tells perltidy to "stack"
closing tokens when possible to avoid lines with isolated closing tokens.
For example:
# default
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
}
);
# -sct
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1,
} );
The -sct flag is somewhat similar to the -vtc flags, and in
some cases it can give a similar result. The difference is that the
-vtc flags try to avoid lines with leading opening tokens by
"hiding" them at the end of a previous line, whereas the
-sct flag merely tries to reduce the number of lines with isolated
closing tokens by stacking them but does not try to hide them. For
example:
# -vtc=2
$opt_c = Text::CSV_XS->new(
{
binary => 1,
sep_char => $opt_c,
always_quote => 1, } );
For detailed control of the stacking of individual closing tokens the
following controls can be used:
-scp or --stack-closing-paren
-schb or --stack-closing-hash-brace
-scsb or --stack-closing-square-bracket
The flag -sct is a synonym for -scp -schb -scsb.
- -dnl, --delete-old-newlines
- By default, perltidy first deletes all old line break
locations, and then it looks for good break points to match the desired
line length. Use -ndnl or --nodelete-old-newlines to force
perltidy to retain all old line break points.
- -anl, --add-newlines
- By default, perltidy will add line breaks when necessary to
create continuations of long lines and to improve the script appearance.
Use -nanl or --noadd-newlines to prevent any new line
breaks.
This flag does not prevent perltidy from eliminating existing line breaks;
see --freeze-newlines to completely prevent changes to line break
points.
- Controlling whether perltidy breaks before or after
operators
- Four command line parameters provide some control over
whether a line break should be before or after specific token types. Two
parameters give detailed control:
-wba=s or --want-break-after=s, and
-wbb=s or --want-break-before=s.
These parameters are each followed by a quoted string, s, containing
a list of token types (separated only by spaces). No more than one of each
of these parameters should be specified, because repeating a command-line
parameter always overwrites the previous one before perltidy ever sees it.
By default, perltidy breaks after these token types:
% + - * / x != == >= <= =~ !~ < > | &
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %=
^= x=
And perltidy breaks before these token types by default:
. << >> -> && || //
To illustrate, to cause a break after a concatenation operator, '.', rather
than before it, the command line would be
-wba="."
As another example, the following command would cause a break before math
operators '+', '-', '/', and '*':
-wbb="+ - / *"
These commands should work well for most of the token types that perltidy
uses (use --dump-token-types for a list). Also try the -D
flag on a short snippet of code and look at the .DEBUG file to see the
tokenization. However, for a few token types there may be conflicts with
hardwired logic which cause unexpected results. One example is curly
braces, which should be controlled with the parameter bl provided
for that purpose.
WARNING Be sure to put these tokens in quotes to avoid having them
misinterpreted by your command shell.
Two additional parameters are available which, though they provide no
further capability, can simplify input are:
-baao or --break-after-all-operators,
-bbao or --break-before-all-operators.
The -baao sets the default to be to break after all of the following
operators:
% + - * / x != == >= <= =~ !~ < > | &
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=
. : ? && || and or err xor
and the -bbao flag sets the default to break before all of these
operators. These can be used to define an initial break preference which
can be fine-tuned with the -wba and -wbb flags. For example,
to break before all operators except an = one could use --bbao
-wba='=' rather than listing every single perl operator except = on
a -wbb flag.
Perltidy attempts to place comma-separated arrays of values in tables which look
good. Its default algorithms usually work well, and they have been improving
with each release, but several parameters are available to control list
formatting.
- -boc, --break-at-old-comma-breakpoints
- This flag tells perltidy to try to break at all old commas.
This is not the default. Normally, perltidy makes a best guess at list
formatting, and seldom uses old comma breakpoints. Usually this works
well, but consider:
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
The default formatting will flatten this down to one line:
# perltidy (default)
my @list = ( 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, );
which hides the structure. Using -boc, plus additional flags to
retain the original style, yields
# perltidy -boc -lp -pt=2 -vt=1 -vtc=1
my @list = (1,
1, 1,
1, 2, 1,
1, 3, 3, 1,
1, 4, 6, 4, 1,);
A disadvantage of this flag is that all tables in the file must already be
nicely formatted. For another possibility see the -fs flag in
"Skipping Selected Sections of Code".
- -mft=n, --maximum-fields-per-table=n
- If the computed number of fields for any table exceeds
n, then it will be reduced to n. The default value for
n is a large number, 40. While this value should probably be left
unchanged as a general rule, it might be used on a small section of code
to force a list to have a particular number of fields per line, and then
either the -boc flag could be used to retain this formatting, or a
single comment could be introduced somewhere to freeze the formatting in
future applications of perltidy.
# perltidy -mft=2
@month_of_year = (
'Jan', 'Feb',
'Mar', 'Apr',
'May', 'Jun',
'Jul', 'Aug',
'Sep', 'Oct',
'Nov', 'Dec'
);
- -cab=n, --comma-arrow-breakpoints=n
- A comma which follows a comma arrow, '=>', requires
special consideration. In a long list, it is common to break at all such
commas. This parameter can be used to control how perltidy breaks at these
commas. (However, it will have no effect if old comma breaks are being
forced because -boc is used). The possible values of n are:
n=0 break at all commas after =>
n=1 stable: break at all commas after => unless this would break
an existing one-line container (default)
n=2 break at all commas after =>, but try to form the maximum
maximum one-line container lengths
n=3 do not treat commas after => specially at all
For example, given the following single line, perltidy by default will not
add any line breaks because it would break the existing one-line
container:
bless { B => $B, Root => $Root } => $package;
Using -cab=0 will force a break after each comma-arrow item:
# perltidy -cab=0:
bless {
B => $B,
Root => $Root
} => $package;
If perltidy is subsequently run with this container broken, then by default
it will break after each '=>' because the container is now broken. To
reform a one-line container, the parameter -cab=2 would be needed.
The flag -cab=3 can be used to prevent these commas from being
treated specially. In this case, an item such as "01" => 31
is treated as a single item in a table. The number of fields in this table
will be determined by the same rules that are used for any other table.
Here is an example.
# perltidy -cab=3
my %last_day = (
"01" => 31, "02" => 29, "03" => 31, "04" => 30,
"05" => 31, "06" => 30, "07" => 31, "08" => 31,
"09" => 30, "10" => 31, "11" => 30, "12" => 31
);
Retaining or Ignoring Existing Line Breaks¶
Several additional parameters are available for controlling the extent to which
line breaks in the input script influence the output script. In most cases,
the default parameter values are set so that, if a choice is possible, the
output style follows the input style. For example, if a short logical
container is broken in the input script, then the default behavior is for it
to remain broken in the output script.
Most of the parameters in this section would only be required for a one-time
conversion of a script from short container lengths to longer container
lengths. The opposite effect, of converting long container lengths to shorter
lengths, can be obtained by temporarily using a short maximum line length.
- -bol, --break-at-old-logical-breakpoints
- By default, if a logical expression is broken at a
"&&", "||", "and", or
"or", then the container will remain broken. Also, breaks at
internal keywords "if" and "unless" will normally be
retained. To prevent this, and thus form longer lines, use
-nbol.
- -bok, --break-at-old-keyword-breakpoints
- By default, perltidy will retain a breakpoint before
keywords which may return lists, such as "sort" and <map>.
This allows chains of these operators to be displayed one per line. Use
-nbok to prevent retaining these breakpoints.
- -bot, --break-at-old-ternary-breakpoints
- By default, if a conditional (ternary) operator is broken
at a ":", then it will remain broken. To prevent this, and
thereby form longer lines, use -nbot.
- -iob, --ignore-old-breakpoints
- Use this flag to tell perltidy to ignore existing line
breaks to the maximum extent possible. This will tend to produce the
longest possible containers, regardless of type, which do not exceed the
line length limit.
- -kis, --keep-interior-semicolons
- Use the -kis flag to prevent breaking at a semicolon
if there was no break there in the input file. Normally perltidy places a
newline after each semicolon which terminates a statement unless several
statements are contained within a one-line brace block. To illustrate,
consider the following input lines:
dbmclose(%verb_delim); undef %verb_delim;
dbmclose(%expanded); undef %expanded;
The default is to break after each statement, giving
dbmclose(%verb_delim);
undef %verb_delim;
dbmclose(%expanded);
undef %expanded;
With perltidy -kis the multiple statements are retained:
dbmclose(%verb_delim); undef %verb_delim;
dbmclose(%expanded); undef %expanded;
The statements are still subject to the specified value of
maximum-line-length and will be broken if this maximum is
exceeed.
Blank Line Control¶
Blank lines can improve the readability of a script if they are carefully
placed. Perltidy has several commands for controlling the insertion,
retention, and removal of blank lines.
- -fbl, --freeze-blank-lines
- Set -fbl if you want to the blank lines in your
script to remain exactly as they are. The rest of the parameters in this
section may then be ignored. (Note: setting the -fbl flag is
equivalent to setting -mbl=0 and -kbl=2).
- -bbc, --blanks-before-comments
- A blank line will be introduced before a full-line comment.
This is the default. Use -nbbc or --noblanks-before-comments
to prevent such blank lines from being introduced.
- -bbs, --blanks-before-subs
- A blank line will be introduced before a sub
definition, unless it is a one-liner or preceded by a comment. A blank
line will also be introduced before a package statement and a
BEGIN and END block. This is the default. The intention is
to help display the structure of a program by setting off certain key
sections of code. This is negated with -nbbs or
--noblanks-before-subs.
- -bbb, --blanks-before-blocks
- A blank line will be introduced before blocks of coding
delimited by for, foreach, while, until, and
if, unless, in the following circumstances:
- •
- The block is not preceded by a comment.
- •
- The block is not a one-line block.
- •
- The number of consecutive non-blank lines at the current
indentation depth is at least -lbl (see next section).
This is the default. The intention of this option is to introduce some space
within dense coding. This is negated with
-nbbb or
--noblanks-before-blocks.
- -lbl=n --long-block-line-count=n
- This controls how often perltidy is allowed to add blank
lines before certain block types (see previous section). The default is 8.
Entering a value of 0 is equivalent to entering a very large
number.
- -mbl=n
--maximum-consecutive-blank-lines=n
- This parameter specifies the maximum number of consecutive
blank lines which will be output within code sections of a script. The
default is n=1. If the input file has more than n consecutive blank lines,
the number will be reduced to n. If n=0 then no blank lines will be
output (unless all old blank lines are retained with the -kbl=2
flag of the next section).
This flag obviously does not apply to pod sections, here-documents, and
quotes.
- -kbl=n, --keep-old-blank-lines=n
- The -kbl=n flag gives you control over how your
existing blank lines are treated.
The possible values of n are:
n=0 ignore all old blank lines
n=1 stable: keep old blanks, but limited by the value of the B<-mbl=n> flag
n=2 keep all old blank lines, regardless of the value of the B<-mbl=n> flag
The default is n=1.
- -sob, --swallow-optional-blank-lines
- This is equivalent to kbl=0 and is included for
compatability with previous versions.
- -nsob, --noswallow-optional-blank-lines
- This is equivalent to kbl=1 and is included for
compatability with previous versions.
Styles¶
A style refers to a convenient collection of existing parameters.
- -gnu, --gnu-style
- -gnu gives an approximation to the GNU Coding
Standards (which do not apply to perl) as they are sometimes implemented.
At present, this style overrides the default style with the following
parameters:
-lp -bl -noll -pt=2 -bt=2 -sbt=2 -icp
- -pbp, --perl-best-practices
- -pbp is an abbreviation for the parameters in the
book Perl Best Practices by Damian Conway:
-l=78 -i=4 -ci=4 -st -se -vt=2 -cti=0 -pt=1 -bt=1 -sbt=1 -bbt=1 -nsfs -nolq
-wbb="% + - * / x != == >= <= =~ !~ < > | & =
**= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x="
Note that the -st and -se flags make perltidy act as a filter on one file
only. These can be overridden with -nst and -nse if necessary.
Other Controls¶
- Deleting selected text
- Perltidy can selectively delete comments and/or pod
documentation. The command -dac or --delete-all-comments
will delete all comments and all pod documentation, leaving just
code and any leading system control lines.
The command -dp or --delete-pod will remove all pod
documentation (but not comments).
Two commands which remove comments (but not pod) are: -dbc or
--delete-block-comments and -dsc or
--delete-side-comments. (Hanging side comments will be deleted with
block comments here.)
The negatives of these commands also work, and are the defaults. When block
comments are deleted, any leading 'hash-bang' will be retained. Also, if
the -x flag is used, any system commands before a leading hash-bang
will be retained (even if they are in the form of comments).
- Writing selected text to a file
- When perltidy writes a formatted text file, it has the
ability to also send selected text to a file with a .TEE extension.
This text can include comments and pod documentation.
The command -tac or --tee-all-comments will write all comments
and all pod documentation.
The command -tp or --tee-pod will write all pod documentation
(but not comments).
The commands which write comments (but not pod) are: -tbc or
--tee-block-comments and -tsc or --tee-side-comments.
(Hanging side comments will be written with block comments here.)
The negatives of these commands also work, and are the defaults.
- Using a .perltidyrc command file
- If you use perltidy frequently, you probably won't be happy
until you create a .perltidyrc file to avoid typing commonly-used
parameters. Perltidy will first look in your current directory for a
command file named .perltidyrc. If it does not find one, it will
continue looking for one in other standard locations.
These other locations are system-dependent, and may be displayed with the
command "perltidy -dpro". Under Unix systems, it will first look
for an environment variable PERLTIDY. Then it will look for a
.perltidyrc file in the home directory, and then for a system-wide
file /usr/local/etc/perltidyrc, and then it will look for
/etc/perltidyrc. Note that these last two system-wide files do not
have a leading dot. Further system-dependent information will be found in
the INSTALL file distributed with perltidy.
Under Windows, perltidy will also search for a configuration file named
perltidy.ini since Windows does not allow files with a leading period (.).
Use "perltidy -dpro" to see the possbile locations for your
system. An example might be C:\Documents and Settings\All
Users\perltidy.ini.
Another option is the use of the PERLTIDY environment variable. The method
for setting environment variables depends upon the version of Windows that
you are using. Instructions for Windows 95 and later versions can be found
here:
http://www.netmanage.com/000/20021101_005_tcm21-6336.pdf
Under Windows NT / 2000 / XP the PERLTIDY environment variable can be placed
in either the user section or the system section. The later makes the
configuration file common to all users on the machine. Be sure to enter
the full path of the configuration file in the value of the environment
variable. Ex. PERLTIDY=C:\Documents and Settings\perltidy.ini
The configuation file is free format, and simply a list of parameters, just
as they would be entered on a command line. Any number of lines may be
used, with any number of parameters per line, although it may be easiest
to read with one parameter per line. Blank lines are ignored, and text
after a '#' is ignored to the end of a line.
Here is an example of a .perltidyrc file:
# This is a simple of a .perltidyrc configuration file
# This implements a highly spaced style
-se # errors to standard error output
-w # show all warnings
-bl # braces on new lines
-pt=0 # parens not tight at all
-bt=0 # braces not tight
-sbt=0 # square brackets not tight
The parameters in the .perltidyrc file are installed first, so any
parameters given on the command line will have priority over them.
To avoid confusion, perltidy ignores any command in the .perltidyrc file
which would cause some kind of dump and an exit. These are:
-h -v -ddf -dln -dop -dsn -dtt -dwls -dwrs -ss
There are several options may be helpful in debugging a .perltidyrc
file:
- •
- A very helpful command is --dump-profile or
-dpro. It writes a list of all configuration filenames tested to
standard output, and if a file is found, it dumps the content to standard
output before exiting. So, to find out where perltidy looks for its
configuration files, and which one if any it selects, just enter
perltidy -dpro
- •
- It may be simplest to develop and test configuration files
with alternative names, and invoke them with -pro=filename on the
command line. Then rename the desired file to .perltidyrc when
finished.
- •
- The parameters in the .perltidyrc file can be
switched off with the -npro option.
- •
- The commands --dump-options, --dump-defaults,
--dump-long-names, and --dump-short-names, all described
below, may all be helpful.
- Creating a new abbreviation
- A special notation is available for use in a
.perltidyrc file for creating an abbreviation for a group of
options. This can be used to create a shorthand for one or more styles
which are frequently, but not always, used. The notation is to group the
options within curly braces which are preceded by the name of the alias
(without leading dashes), like this:
newword {
-opt1
-opt2
}
where newword is the abbreviation, and opt1, etc, are existing
parameters or other abbreviations. The main syntax requirement is
that the new abbreviation must begin on a new line. Space before and after
the curly braces is optional. For a specific example, the following line
airy {-bl -pt=0 -bt=0 -sbt=0}
could be placed in a .perltidyrc file, and then invoked at will with
perltidy -airy somefile.pl
(Either "-airy" or "--airy" may be used).
- Skipping leading non-perl commands with -x or
--look-for-hash-bang
- If your script has leading lines of system commands or
other text which are not valid perl code, and which are separated from the
start of the perl code by a "hash-bang" line, ( a line of the
form "#!...perl" ), you must use the -x flag to tell
perltidy not to parse and format any lines before the
"hash-bang" line. This option also invokes perl with a -x flag
when checking the syntax. This option was originally added to allow
perltidy to parse interactive VMS scripts, but it should be used for any
script which is normally invoked with "perl -x".
- Making a file unreadable
- The goal of perltidy is to improve the readability of
files, but there are two commands which have the opposite effect,
--mangle and --extrude. They are actually merely aliases for
combinations of other parameters. Both of these strip all possible
whitespace, but leave comments and pod documents, so that they are
essentially reversible. The difference between these is that
--mangle puts the fewest possible line breaks in a script while
--extrude puts the maximum possible. Note that these options do not
provided any meaningful obfuscation, because perltidy can be used to
reformat the files. They were originally developed to help test the
tokenization logic of perltidy, but they have other uses. One use for
--mangle is the following:
perltidy --mangle myfile.pl -st | perltidy -o myfile.pl.new
This will form the maximum possible number of one-line blocks (see next
section), and can sometimes help clean up a badly formatted script.
A similar technique can be used with --extrude instead of
--mangle to make the minimum number of one-line blocks.
Another use for --mangle is to combine it with -dac to reduce
the file size of a perl script.
- One-line blocks
- There are a few points to note regarding one-line blocks. A
one-line block is something like this,
if ($x > 0) { $y = 1 / $x }
where the contents within the curly braces is short enough to fit on a
single line.
With few exceptions, perltidy retains existing one-line blocks, if it is
possible within the line-length constraint, but it does not attempt to
form new ones. In other words, perltidy will try to follow the one-line
block style of the input file.
If an existing one-line block is longer than the maximum line length,
however, it will be broken into multiple lines. When this happens,
perltidy checks for and adds any optional terminating semicolon (unless
the -nasc option is used) if the block is a code block.
The main exception is that perltidy will attempt to form new one-line blocks
following the keywords "map", "eval", and
"sort", because these code blocks are often small and most
clearly displayed in a single line.
One-line block rules can conflict with the cuddled-else option. When the
cuddled-else option is used, perltidy retains existing one-line blocks,
even if they do not obey cuddled-else formatting.
Occasionally, when one-line blocks get broken because they exceed the
available line length, the formatting will violate the requested brace
style. If this happens, reformatting the script a second time should
correct the problem.
- Debugging
- The following flags are available for debugging:
--dump-defaults or -ddf will write the default option set to
standard output and quit
--dump-profile or -dpro will write the name of the current
configuration file and its contents to standard output and quit.
--dump-options or -dop will write current option set to
standard output and quit.
--dump-long-names or -dln will write all command line long
names (passed to Get_options) to standard output and quit.
--dump-short-names or -dsn will write all command line short
names to standard output and quit.
--dump-token-types or -dtt will write a list of all token
types to standard output and quit.
--dump-want-left-space or -dwls will write the hash
%want_left_space to standard output and quit. See the section on
controlling whitespace around tokens.
--dump-want-right-space or -dwrs will write the hash
%want_right_space to standard output and quit. See the section on
controlling whitespace around tokens.
-DEBUG will write a file with extension .DEBUG for each input
file showing the tokenization of all lines of code.
- Working with MakeMaker, AutoLoader and SelfLoader
- The first $VERSION line of a file which might be eval'd by
MakeMaker is passed through unchanged except for indentation. Use
--nopass-version-line, or -npvl, to deactivate this feature.
If the AutoLoader module is used, perltidy will continue formatting code
after seeing an __END__ line. Use --nolook-for-autoloader, or
-nlal, to deactivate this feature.
Likewise, if the SelfLoader module is used, perltidy will continue
formatting code after seeing a __DATA__ line. Use
--nolook-for-selfloader, or -nlsl, to deactivate this
feature.
- Working around problems with older version of Perl
- Perltidy contains a number of rules which help avoid known
subtleties and problems with older versions of perl, and these rules
always take priority over whatever formatting flags have been set. For
example, perltidy will usually avoid starting a new line with a bareword,
because this might cause problems if "use strict" is active.
There is no way to override these rules.
HTML OPTIONS¶
- The -html master switch
- The flag -html causes perltidy to write an html file
with extension .html. So, for example, the following command
perltidy -html somefile.pl
will produce a syntax-colored html file named somefile.pl.html which
may be viewed with a browser.
Please Note: In this case, perltidy does not do any formatting to
the input file, and it does not write a formatted file with extension
.tdy. This means that two perltidy runs are required to create a
fully reformatted, html copy of a script.
- The -pre flag for code snippets
- When the -pre flag is given, only the pre-formatted
section, within the <PRE> and </PRE> tags, will be output.
This simplifies inclusion of the output in other files. The default is to
output a complete web page.
- The -nnn flag for line numbering
- When the -nnn flag is given, the output lines will
be numbered.
- The -toc, or --html-table-of-contents
flag
- By default, a table of contents to packages and subroutines
will be written at the start of html output. Use -ntoc to prevent
this. This might be useful, for example, for a pod document which contains
a number of unrelated code snippets. This flag only influences the code
table of contents; it has no effect on any table of contents produced by
pod2html (see next item).
- The -pod, or --pod2html flag
- There are two options for formatting pod documentation. The
default is to pass the pod through the Pod::Html module (which forms the
basis of the pod2html utility). Any code sections are formatted by
perltidy, and the results then merged. Note: perltidy creates a temporary
file when Pod::Html is used; see "FILES". Also, Pod::Html
creates temporary files for its cache.
NOTE: Perltidy counts the number of "=cut" lines, and either moves
the pod text to the top of the html file if there is one "=cut",
or leaves the pod text in its original order (interleaved with code)
otherwise.
Most of the flags accepted by pod2html may be included in the perltidy
command line, and they will be passed to pod2html. In some cases, the
flags have a prefix "pod" to emphasize that they are for the
pod2html, and this prefix will be removed before they are passed to
pod2html. The flags which have the additional "pod" prefix are:
--[no]podheader --[no]podindex --[no]podrecurse --[no]podquiet
--[no]podverbose --podflush
The flags which are unchanged from their use in pod2html are:
--backlink=s --cachedir=s --htmlroot=s --libpods=s --title=s
--podpath=s --podroot=s
where 's' is an appropriate character string. Not all of these flags are
available in older versions of Pod::Html. See your Pod::Html documentation
for more information.
The alternative, indicated with -npod, is not to use Pod::Html, but
rather to format pod text in italics (or whatever the stylesheet
indicates), without special html markup. This is useful, for example, if
pod is being used as an alternative way to write comments.
- The -frm, or --frames flag
- By default, a single html output file is produced. This can
be changed with the -frm option, which creates a frame holding a
table of contents in the left panel and the source code in the right side.
This simplifies code browsing. Assume, for example, that the input file is
MyModule.pm. Then, for default file extension choices, these three
files will be created:
MyModule.pm.html - the frame
MyModule.pm.toc.html - the table of contents
MyModule.pm.src.html - the formatted source code
Obviously this file naming scheme requires that output be directed to a real
file (as opposed to, say, standard output). If this is not the case, or if
the file extension is unknown, the -frm option will be
ignored.
- The -text=s, or --html-toc-extension
flag
- Use this flag to specify the extra file extension of the
table of contents file when html frames are used. The default is
"toc". See "Specifying File Extensions".
- The -sext=s, or --html-src-extension
flag
- Use this flag to specify the extra file extension of the
content file when html frames are used. The default is "src".
See "Specifying File Extensions".
- The -hent, or --html-entities flag
- This flag controls the use of Html::Entities for html
formatting. By default, the module Html::Entities is used to encode
special symbols. This may not be the right thing for some browser/language
combinations. Use --nohtml-entities or -nhent to prevent this.
- Style Sheets
- Style sheets make it very convenient to control and adjust
the appearance of html pages. The default behavior is to write a page of
html with an embedded style sheet.
An alternative to an embedded style sheet is to create a page with a link to
an external style sheet. This is indicated with the -css=filename,
where the external style sheet is filename. The external style
sheet filename will be created if and only if it does not exist.
This option is useful for controlling multiple pages from a single style
sheet.
To cause perltidy to write a style sheet to standard output and exit, use
the -ss, or --stylesheet, flag. This is useful if the style
sheet could not be written for some reason, such as if the -pre
flag was used. Thus, for example,
perltidy -html -ss >mystyle.css
will write a style sheet with the default properties to file
mystyle.css.
The use of style sheets is encouraged, but a web page without a style sheets
can be created with the flag -nss. Use this option if you must to
be sure that older browsers (roughly speaking, versions prior to 4.0 of
Netscape Navigator and Internet Explorer) can display the syntax-coloring
of the html files.
- Controlling HTML properties
- Note: It is usually more convenient to accept the default
properties and then edit the stylesheet which is produced. However, this
section shows how to control the properties with flags to perltidy.
Syntax colors may be changed from their default values by flags of the
either the long form, -html-color-xxxxxx=n, or more conveniently
the short form, -hcx=n, where xxxxxx is one of the following
words, and x is the corresponding abbreviation:
Token Type xxxxxx x
---------- -------- --
comment comment c
number numeric n
identifier identifier i
bareword, function bareword w
keyword keyword k
quite, pattern quote q
here doc text here-doc-text h
here doc target here-doc-target hh
punctuation punctuation pu
parentheses paren p
structural braces structure s
semicolon semicolon sc
colon colon co
comma comma cm
label label j
sub definition name subroutine m
pod text pod-text pd
A default set of colors has been defined, but they may be changed by
providing values to any of the following parameters, where n is
either a 6 digit hex RGB color value or an ascii name for a color, such as
'red'.
To illustrate, the following command will produce an html file
somefile.pl.html with "aqua" keywords:
perltidy -html -hck=00ffff somefile.pl
and this should be equivalent for most browsers:
perltidy -html -hck=aqua somefile.pl
Perltidy merely writes any non-hex names that it sees in the html file. The
following 16 color names are defined in the HTML 3.2 standard:
black => 000000,
silver => c0c0c0,
gray => 808080,
white => ffffff,
maroon => 800000,
red => ff0000,
purple => 800080,
fuchsia => ff00ff,
green => 008000,
lime => 00ff00,
olive => 808000,
yellow => ffff00
navy => 000080,
blue => 0000ff,
teal => 008080,
aqua => 00ffff,
Many more names are supported in specific browsers, but it is safest to use
the hex codes for other colors. Helpful color tables can be located with
an internet search for "HTML color tables".
Besides color, two other character attributes may be set: bold, and italics.
To set a token type to use bold, use the flag --html-bold-xxxxxx or
-hbx, where xxxxxx or x are the long or short names
from the above table. Conversely, to set a token type to NOT use bold, use
--nohtml-bold-xxxxxx or -nhbx.
Likewise, to set a token type to use an italic font, use the flag
--html-italic-xxxxxx or -hix, where again xxxxxx or
x are the long or short names from the above table. And to set a
token type to NOT use italics, use --nohtml-italic-xxxxxx or
-nhix.
For example, to use bold braces and lime color, non-bold, italics keywords
the following command would be used:
perltidy -html -hbs -hck=00FF00 -nhbk -hik somefile.pl
The background color can be specified with --html-color-background=n,
or -hcbg=n for short, where n is a 6 character hex RGB value. The
default color of text is the value given to punctuation, which is
black as a default.
Here are some notes and hints:
1. If you find a preferred set of these parameters, you may want to create a
.perltidyrc file containing them. See the perltidy man page for an
explanation.
2. Rather than specifying values for these parameters, it is probably easier
to accept the defaults and then edit a style sheet. The style sheet
contains comments which should make this easy.
3. The syntax-colored html files can be very large, so it may be best to
split large files into smaller pieces to improve download times.
Specifying Block Types¶
Several parameters which refer to code block types may be customized by also
specifying an associated list of block types. The type of a block is the name
of the keyword which introduces that block, such as
if,
else, or
sub. An exception is a labeled block, which has no keyword, and should
be specified with just a colon.
For example, the following parameter specifies "sub", labels,
"BEGIN", and "END" blocks:
-cscl="sub : BEGIN END"
(the meaning of the -cscl parameter is described above.) Note that quotes are
required around the list of block types because of the spaces.
Specifying File Extensions¶
Several parameters allow default file extensions to be overridden. For example,
a backup file extension may be specified with
-bext=ext, where
ext is some new extension. In order to provides the user some
flexibility, the following convention is used in all cases to decide if a
leading '.' should be used. If the extension "ext" begins with
"A-Z", "a-z", or "0-9", then it will be appended
to the filename with an intermediate '.' (or perhaps an '_' on VMS systems).
Otherwise, it will be appended directly.
For example, suppose the file is
somefile.pl. For "-bext=old",
a '.' is added to give
somefile.pl.old. For "-bext=.old", no
additional '.' is added, so again the backup file is
somefile.pl.old.
For "-bext=~", then no dot is added, and the backup file will be
somefile.pl~ .
SWITCHES WHICH MAY BE NEGATED¶
The following list shows all short parameter names which allow a prefix 'n' to
produce the negated form:
D anl asc aws b bbb bbc bbs bl bli boc bok bol bot ce
csc dac dbc dcsc ddf dln dnl dop dp dpro dsc dsm dsn dtt dwls
dwrs dws f fll frm fs hsc html ibc icb icp iob isbc lal log
lp lsl ohbr okw ola oll opr opt osbr otr ple ple pod pvl q
sbc sbl schb scp scsb sct se sfp sfs skp sob sohb sop sosb sot
ssc st sts syn t tac tbc toc tp tqw tsc w x bar kis
Equivalently, the prefix 'no' or 'no-' on the corresponding long names may be
used.
LIMITATIONS¶
- Parsing Limitations
- Perltidy should work properly on most perl scripts. It does
a lot of self-checking, but still, it is possible that an error could be
introduced and go undetected. Therefore, it is essential to make careful
backups and to test reformatted scripts.
The main current limitation is that perltidy does not scan modules included
with 'use' statements. This makes it necessary to guess the context of any
bare words introduced by such modules. Perltidy has good guessing
algorithms, but they are not infallible. When it must guess, it leaves a
message in the log file.
If you encounter a bug, please report it.
- What perltidy does not parse and format
- Perltidy indents but does not reformat comments and
"qw" quotes. Perltidy does not in any way modify the contents of
here documents or quoted text, even if they contain source code. (You
could, however, reformat them separately). Perltidy does not format
'format' sections in any way. And, of course, it does not modify pod
documents.
FILES¶
- Temporary files
- Under the -html option with the default --pod2html flag, a
temporary file is required to pass text to Pod::Html. Unix systems will
try to use the POSIX tmpnam() function. Otherwise the file
perltidy.TMP will be temporarily created in the current working
directory.
- Special files when standard input is used
- When standard input is used, the log file, if saved, is
perltidy.LOG, and any errors are written to perltidy.ERR
unless the -se flag is set. These are saved in the current working
directory.
- Files overwritten
- The following file extensions are used by perltidy, and
files with these extensions may be overwritten or deleted: .ERR,
.LOG, .TEE, and/or .tdy, .html, and
.bak, depending on the run type and settings.
- Files extensions limitations
- Perltidy does not operate on files for which the run could
produce a file with a duplicated file extension. These extensions include
.LOG, .ERR, .TEE, and perhaps .tdy and
.bak, depending on the run type. The purpose of this rule is to
prevent generating confusing filenames such as
somefile.tdy.tdy.tdy.
SEE ALSO¶
perlstyle(1),
Perl::Tidy(3)
VERSION¶
This man page documents perltidy version 20101217.
CREDITS¶
Michael Cartmell supplied code for adaptation to VMS and helped with v-strings.
Yves Orton supplied code for adaptation to the various versions of Windows.
Axel Rose supplied a patch for MacPerl.
Hugh S. Myers designed and implemented the initial Perl::Tidy module interface.
Many others have supplied key ideas, suggestions, and bug reports; see the
CHANGES file.
AUTHOR¶
Steve Hancock
email: perltidy at users.sourceforge.net
http://perltidy.sourceforge.net
COPYRIGHT¶
Copyright (c) 2000-2010 by Steve Hancock
LICENSE¶
This package is free software; you can redistribute it and/or modify it under
the terms of the "GNU General Public License".
Please refer to the file "COPYING" for details.
DISCLAIMER¶
This package is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.
See the "GNU General Public License" for more details.