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, the output will go to filename.tdy.

-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, and for eliminating the backup file altogether.

A -b flag will be ignored if input is from standard input or goes to standard output, or if the -html flag is set.

In particular, if you want to use both the -b flag and the -pbp (--perl-best-practices) flag, then you must put a -nst flag after the -pbp flag because it contains a -st flag as one of its components, which means that output will go to the standard output stream.

-bext=ext, --backup-file-extension=ext

This parameter serves two purposes: (1) to change the extension of the backup file to be something other than the default .bak, and (2) to indicate that no backup file should be saved.

To change the default extension to something other than .bak see "Specifying File Extensions".

A backup file of the source is always written, but you can request that it be deleted at the end of processing if there were no errors. This is risky unless the source code is being maintained with a source code control system.

To indicate that the backup should be deleted include one forward slash, /, in the extension. If any text remains after the slash is removed it will be used to define the backup file extension (which is always created and only deleted if there were no errors).

Here are some examples:

  Parameter           Extension          Backup File Treatment
  <-bext=bak>         F<.bak>            Keep (same as the default behavior)
  <-bext='/'>         F<.bak>            Delete if no errors
  <-bext='/backup'>   F<.backup>         Delete if no errors
  <-bext='original/'> F<.original>       Delete if no errors
    

-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.

-i=n, --indent-columns=n

Use n columns per indentation level (default n=4).

-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).

-vmll, --variable-maximum-line-length

A problem arises using a fixed maximum line length with very deeply nested code and data structures because eventually the amount of leading whitespace used for indicating indentation takes up most or all of the available line width, leaving little or no space for the actual code or data. One solution is to use a vary long line length. Another solution is to use the -vmll flag, which basically tells perltidy to ignore leading whitespace when measuring the line length.

To be precise, when the -vmll parameter is set, the maximum line length of a line of code will be M+L*I, where

      M is the value of --maximum-line-length=M (-l=M), default 80,
      I is the value of --indent-columns=I (-i=I), default 4,
      L is the indentation level of the line of code
    

When this flag is set, the choice of breakpoints for a block of code should be essentially independent of its nesting depth. However, the absolute line lengths, including leading whitespace, can still be arbitrarily large. This problem can be avoided by including the next parameter.

The default is not to do this (-nvmll).

-wc=n, --whitespace-cycle=n

This flag also addresses problems with very deeply nested code and data structures. When the nesting depth exceeds the value n the leading whitespace will be reduced and start at a depth of 1 again. The result is that blocks of code will shift back to the left rather than moving arbitrarily far to the right. This occurs cyclically to any depth.

For example if one level of indentation equals 4 spaces (-i=4, the default), and one uses -wc=15, then if the leading whitespace on a line exceeds about 4*15=60 spaces it will be reduced back to 4*1=4 spaces and continue increasing from there. If the whitespace never exceeds this limit the formatting remains unchanged.

The combination of -vmll and -wc=n provides a solution to the problem of displaying arbitrarily deep data structures and code in a finite window, although -wc=n may of course be used without -vmll.

The default is not to use this, which can also be indicated using -wc=0.

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.

-syn, --check-syntax

This flag is now ignored for safety, but the following documentation has been retained for reference.

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.

-xs, --extended-syntax

A problem with formatting Perl code is that some modules can introduce new syntax. This flag allows perltidy to handle certain common extensions to the standard syntax without complaint.

For example, without this flag a structure such as the following would generate a syntax error and the braces would not be balanced:

    method deposit( Num $amount) {
        $self->balance( $self->balance + $amount );
    }
    

This flag is enabled by default but it can be deactivated with -nxs. Probably the only reason to deactivate this flag is to generate more diagnostic messages when debugging a script.

-io, --indent-only

This flag is used to deactivate all whitespace 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 to the number of 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.

With this option perltidy is still free to modify the indenting (and outdenting) of code and comments as it normally would. If you also want to prevent long comment lines from being outdented, you can add either -noll or -l=0.

Setting this flag will prevent perltidy from doing any special operations on closing side comments. You may still delete all side comments however when this flag is in effect.

-enc=s, --character-encoding=s

where s=none or utf8. This flag tells perltidy the character encoding of both the input and output character streams. The value utf8 causes the stream to be read and written as UTF-8. The value none causes the stream to be processed without special encoding assumptions. At present there is no automatic detection of character encoding (even if there is a 'use utf8' statement in your code) so this flag must be set for streams encoded in UTF-8. Incorrectly setting this parameter can cause data corruption, so please carefully check the output.

The default is none.

The abbreviations -utf8 or -UTF8 are equivalent to -enc=utf8. So to process a file named file.pl which is encoded in UTF-8 you can use:

   perltidy -utf8 file.pl
    

-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 an 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. It has been found to be extremely rare for the output to change after 2 iterations. If a value n is greater than 2 is input then a convergence test will be used to stop the iterations as soon as possible, almost always after 2 iterations. See the next item for a simplified iteration control.

This flag has no effect when perltidy is used to generate html.

-conv, --converge

This flag is equivalent to -it=4 and is included to simplify iteration control. For all practical purposes one either does or does not want to be sure that the output is converged, and there is no penalty to using a large iteration limit since perltidy will check for convergence and stop iterating as soon as possible. The default is -nconv (no convergence check). Using -conv will approximately double run time since normally one extra iteration is required to verify convergence.

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.

To guess the starting indentation level perltidy simply assumes that indentation scheme used to create the code snippet is the same as is being used for the current perltidy process. This is the only sensible guess that can be made. It should be correct if this is true, but otherwise it probably won't. For example, if the input script was written with -i=2 and the current peltidy flags have -i=4, the wrong initial indentation will be guessed for a code snippet which has non-zero initial indentation. Likewise, if an entabbing scheme is used in the input script and not in the current process then the guessed indentation will be wrong.

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 compatibility.

-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

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
    

To simplify input in the case that all of the tightness flags have the same value <n>, the parameter <-act=n> or --all-containers-tightness=n is an abbreviation for the combination <-pt=n -sbt=n -bt=n -bbt=n>.

-tso, --tight-secret-operators

The flag -tso causes certain perl token sequences (secret operators) which might be considered to be a single operator to be formatted "tightly" (without spaces). The operators currently modified by this flag are:

     0+  +0  ()x!! ~~<>  ,=>   =( )=
    

For example the sequence 0 +, which converts a string to a number, would be formatted without a space: 0+ when the -tso flag is set. This flag is off by default.

-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"
    

The abbreviation -nsak='*' is equivalent to including all of the keywords in the above list.

When both -nsak=s and -sak=s commands are included, the -nsak=s command is executed first. For example, to have space after only the keywords (my, local, our) you could use -nsak="*" -sak="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.

-sbq=n or --space-backslash-quote=n

Lines like

       $str1=\"string1";
       $str2=\'string2';
    

can confuse syntax highlighters unless a space is included between the backslash and the single or double quotation mark.

This can be controlled with the value of n as follows:

    -sbq=0 means no space between the backslash and quote
    -sbq=1 means follow the example of the source code
    -sbq=2 means always put a space between the backslash and quote
    

The default is -sbq=1, meaning that a space will be used 0if there is one in the source code.

Trimming trailing whitespace from lines of POD

-trp or --trim-pod will remove trailing whitespace from lines of POD. The default is not to do this.

Comment Controls¶

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, will not do this.

-iscl, --ignore-side-comment-lengths

This parameter causes perltidy to ignore the length of side comments when setting line breaks. The default, -niscl, is to include the length of side comments when breaking lines to stay within the length prescribed by the -l=n maximum line length parameter. For example, the following long single line would remain intact with -l=80 and -iscl:

     perltidy -l=80 -iscl
        $vmsfile =~ s/;[\d\-]*$//; # Clip off version number; we can use a newer version as well
    

whereas without the -iscl flag the line will be broken:

     perltidy -l=80
        $vmsfile =~ s/;[\d\-]*$//
          ;    # Clip off version number; we can use a newer version as well
    

-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:

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.

    @month_of_year = (    # -sbc (default)
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
    ##  'Dec', 'Nov'
        'Nov', 'Dec');

    @month_of_year = (   # -nsbc
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
  
        ##  'Dec', 'Nov'
        'Nov', 'Dec'
    );

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.

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();
  }
    

-cb, --cuddled-blocks

This flag enables the "cuddled else" format style on a chain of specified block types. The default is to apply it to a chain consisting of try-catch-finally blocks, but it can apply to any desired chain of blocks by specifying their names on a separate parameter -cbl, described in the next section.

    # perltidy -cb:
    try {
        throw Error::Simple( "ok 2\n", 2 );
    } catch Error::Simple with {
        my $err = shift;
        print "$err";
    } finally {
        print "ok 3\n";
    };
    

Cuddling between a pair of code blocks requires that the closing brace of the first block start a new line. If this block is entirely on one line in the input file, it is necessary to decide if it should be broken to allow cuddling. This decision is controlled by the flag -cbo=n discussed below. The default and recommended value of -cbo=1 bases this decision on the first block in the chain. If it spans multiple lines then cuddling is made and continues along the chain, regardless of the sizes of subsequent blocks. Otherwise, short lines remain intact.

So for example, the -cb flag would not have any effect if the above snippet is rewritten as

    try { throw Error::Simple( "ok 2\n", 2 ); }
    catch Error::Simple with { my $err = shift; print "$err"; }
    finally { print "ok 3\n"; };
    

If the first block spans multiple lines, then cuddling can be done and will continue for the subsequent blocks in the chain, as illustrated in the previous snippet.

If there are blank lines between cuddled blocks they will be eliminated. If there are comments after the closing brace where cuddling would occur then cuddling will be prevented. If this occurs, cuddling will restart later in the chain if possible.

The default for this parameter is --nocuddled-blocks

-cbl, --cuddled-block-list

The block types to which the -cuddled-blocks style applies is defined by this parameter. This parameter is a character string, giving a list of block types separated by dashes.

The default value for this string is

   -cbl="try-catch-finally"
    

This string will cause cuddled formatting to be applied to every block in a chain starting with a "try" and followed by any number of "catch" and "finally" blocks.

In general, a string describing a chain of blocks has the form

   -cbl="word1-word2-word3-...-wordn"
    

In this case, a chain begins when an opening block brace preceded by word1 in the list is encountered. The chain continues if the closing block brace is followed immediately by any of word2, word3, etc.

If the leading word, word1, might be repeated later in a chain then it should also be included amoung the secondary words.

Multiple chain types may be specified by separating the strings with commas or spaces. So for example if we have two chains of code blocks, f1-f2-f3 and g1-g2-g3-g4, they could be specified as

   -cbl="f1-f2-f3  g1-g2-g3-g4"
or
   -cbl=f1-f2-f3,g1-g2-g3-g4
    

Spaces are easier to read but commas may avoid quotation difficulties when entering data in a command shell.

To define secondary words that apply to all block types, other than those explicitly specified, the leading word can be omitted. For example, the built-in cuddled-else format specified by the -ce flag can be approximately specified by

   -cbl="if-else-elsif unless-else-elsif -continue"
or
   -cbl=if-else-elsif,unless-else-elsif,-continue
    

The final string -continue allows cuddling the optional continue block which may follow may other block types.

As a diagnostic check, the flag --dump-cuddled-block-list or -dcbl can be used to view the hash of values this flag creates.

Finally, note that the -cbl flag by itself merely specifies which blocks are formatted with the cuddled format. It has no effect unless this formatting style is activated with -cb.

-cbo=n, --cuddled-break-option=n

Cuddled formatting is only possible between a pair of code blocks if the closing brace of the first block starts a new line. If a block is encountered which is entirely on a single line, and cuddled formatting is selected, it is necessary to make a decision as to whether or not to "break" the block, meaning to cause it to span multiple lines. This parameter controls that decision. The options are:

   cbo=0  Never force a short block to break.
   cbo=1  If the first of a pair of blocks is broken in the input file, 
          then break the second.
   cbo=2  Break open all blocks for maximal cuddled formatting.
    

The default and recommended value is cbo=1. With this value, if the starting block of a chain spans multiple lines, then a cascade of breaks will occur for remaining blocks causing the entire chain to be cuddled.

The option cbo=0 can produce erratic cuddling if there are numerous one-line blocks.

The option cbo=2 produces maximal cuddling but will not allow any short blocks.

Note: at present, this option currently only applies to blocks controlled by the -cb flag. Cuddling under the -ce flag corresponds approximately to -cbo=1 but cannot currently be changed.

-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 an abbreviation 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
    

-wn, --weld-nested-containers

The -wn flag causes closely nested pairs of opening and closing container symbols (curly braces, brackets, or parens) to be "welded" together, meaning that they are treated as if combined into a single unit, with the indentation of the innermost code reduced to be as if there were just a single container symbol.

For example:

        # default formatting
        do {
            {
                next if $x == $y;    
            }
        } until $x++ > $z;
        # perltidy -wn
        do { {
            next if $x == $y;
        } } until $x++ > $z;
    

When this flag is set perltidy makes a preliminary pass through the file and identifies all nested pairs of containers. To qualify as a nested pair, the closing container symbols must be immediately adjacent. The opening symbols must either be adjacent, or, if the outer opening symbol is an opening paren, they may be separated by any single non-container symbol or something that looks like a function evaluation.

Any container symbol may serve as both the inner container of one pair and as the outer container of an adjacent pair. Consequently, any number of adjacent opening or closing symbols may join together in weld. For example, here are three levels of wrapped function calls:

        # default formatting
        my (@date_time) = Localtime(
            Date_to_Time(
                Add_Delta_DHMS(
                    $year, $month,  $day, $hour, $minute, $second,
                    '0',   $offset, '0',  '0'
                )
            )
        );
        # perltidy -wn
        my (@date_time) = Localtime( Date_to_Time( Add_Delta_DHMS(
            $year, $month,  $day, $hour, $minute, $second,
            '0',   $offset, '0',  '0'
        ) ) );
    

Notice how the indentation of the inner lines are reduced by two levels in this case. This example also shows the typical result of this formatting, namely it is a sandwich consisting of an initial opening layer, a central section of any complexity forming the "meat" of the sandwich, and a final closing layer. This predictable structure helps keep the compacted structure readable.

The inner sandwich layer is required to be at least one line thick. If this cannot be achieved, welding does not occur. This constraint can cause formatting to take a couple of iterations to stabilize when it is first applied to a script. The -conv flag can be used to insure that the final format is achieved in a single run.

Here is an example illustrating a welded container within a welded containers:

        # default formatting
        $x->badd(
            bmul(
                $class->new(
                    abs(
                        $sx * int( $xr->numify() ) & $sy * int( $yr->numify() )
                    )
                ),
                $m
            )
        );
        # perltidy -wn
        $x->badd( bmul(
            $class->new( abs(
                $sx * int( $xr->numify() ) & $sy * int( $yr->numify() )
            ) ),
            $m
        ) );
    

This format option is quite general but there are some limitations.

One limitiation is that any line length limit still applies and can cause long welded sections to be broken into multiple lines.

Another limitation is that an opening symbol which delimits quoted text cannot be included in a welded pair. This is because quote delimiters are treated specially in perltidy.

Finally, the stacking of containers defined by this flag have priority over any other container stacking flags. This is because any welding is done first.

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:

    # 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', );

    # 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 ] )
                )
    );

    # perltidy -lp -vt=2 -vtc=2
    $init->add( mysprintf( "(void)find_threadsv(%s);",
                           cstring( $threadsv_names[ $op->targ ] ) ) );

-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 one exception they will be placed on separate lines. The exception is that a cascade of closing block braces may be stacked on a single line. See -scbb.

-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
  -sobb or --stack-opening-block-brace
    

The flag -sot is an abbreviation for -sop -sohb -sosb.

The flag -sobb is a abbreviation for -bbvt=2 -bbvtl='*'. This will case a cascade of opening block braces to appear on a single line, although this an uncommon occurrence except in test scripts.

-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
  -scbb or --stack-closing-block-brace
    

The flag -sct is an abbreviation for stacking the non-block closing tokens, -scp -schb -scsb.

Stacking of closing block braces, -scbb, causes a cascade of isolated closing block braces to be combined into a single line as in the following example:

    # -scbb:
    for $w1 (@w1) {
        for $w2 (@w2) {
            for $w3 (@w3) {
                for $w4 (@w4) {
                    push( @lines, "$w1 $w2 $w3 $w4\n" );
                } } } }
    

To simplify input even further for the case in which both opening and closing non-block containers are stacked, the flag -sac or --stack-all-containers is an abbreviation for -sot -sot.

-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.

Controlling List Formatting¶

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, '=>', is given 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 => if container is open,
     EXCEPT FOR one-line containers
 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 
 n=4 break everything: like n=0 but ALSO break a short container with
     a => not followed by a comma when -vt=0 is used
 n=5 stable: like n=1 but ALSO break at open one-line containers when
     -vt=0 is used (default)
    

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 could be used.

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.

-boa, --break-at-old-attribute-breakpoints

By default, if an attribute list is broken at a ":" in the source file, then it will remain broken. For example, given the following code, the line breaks at the ':'s will be retained:

                    my @field
                      : field
                      : Default(1)
                      : Get('Name' => 'foo') : Set('Name');
    

If the attributes are on a single line in the source code then they will remain on a single line if possible.

To prevent this, and thereby always form longer lines, use -nboa.

-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 exceeded.

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.

-blbs=n, --blank-lines-before-subs=n

The parameter -blbs=n requests that least n blank lines precede a sub definition which does not follow a comment and which is more than one-line long. The default is <-blbs=1>. BEGIN and END blocks are included.

The requested number of blanks statement will be inserted regardless of the value of --maximum-consecutive-blank-lines=n (-mbl=n) with the exception that if -mbl=0 then no blanks will be output.

This parameter interacts with the value k of the parameter --maximum-consecutive-blank-lines=k (-mbl=k) as follows:

1. If -mbl=0 then no blanks will be output. This allows all blanks to be suppressed with a single parameter. Otherwise,

2. If the number of old blank lines in the script is less than n then additional blanks will be inserted to make the total n regardless of the value of -mbl=k.

3. If the number of old blank lines in the script equals or exceeds n then this parameter has no effect, however the total will not exceed value specified on the -mbl=k flag.

-blbp=n, --blank-lines-before-packages=n

The parameter -blbp=n requests that least n blank lines precede a package which does not follow a comment. The default is -blbp=1.

This parameter interacts with the value k of the parameter --maximum-consecutive-blank-lines=k (-mbl=k) in the same way as described for the previous item -blbs=n.

-bbs, --blanks-before-subs

For compatibility with previous versions, -bbs or --blanks-before-subs is equivalent to -blbp=1 and -blbs=1.

Likewise, -nbbs or --noblanks-before-subs is equivalent to -blbp=0 and -blbs=0.

-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:

-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.

-blao=i or --blank-lines-after-opening-block=i

This control places a minimum of i blank lines after a line which ends with an opening block brace of a specified type. By default, this only applies to the block of a named sub, but this can be changed (see -blaol below). The default is not to do this (i=0).

Please see the note below on using the -blao and -blbc options.

-blbc=i or --blank-lines-before-closing-block=i

This control places a minimum of i blank lines before a line which begins with a closing block brace of a specified type. By default, this only applies to the block of a named sub, but this can be changed (see -blbcl below). The default is not to do this (i=0).

-blaol=s or --blank-lines-after-opening-block-list=s

The parameter s is a list of block type keywords to which the flag -blao should apply. The section "Specifying Block Types" explains how to list block types.

-blbcl=s or --blank-lines-before-closing-block-list=s

This parameter is a list of block type keywords to which the flag -blbc should apply. The section "Specifying Block Types" explains how to list block types.

Note on using the -blao and -blbc options.

These blank line controls introduce a certain minimum number of blank lines in the text, but the final number of blank lines may be greater, depending on values of the other blank line controls and the number of old blank lines. A consequence is that introducing blank lines with these and other controls cannot be exactly undone, so some experimentation with these controls is recommended before using them.

For example, suppose that for some reason we decide to introduce one blank space at the beginning and ending of all blocks. We could do this using

  perltidy -blao=2 -blbc=2 -blaol='*' -blbcl='*' filename
    

Now suppose the script continues to be developed, but at some later date we decide we don't want these spaces after all. we might expect that running with the flags -blao=0 and -blbc=0 will undo them. However, by default perltidy retains single blank lines, so the blank lines remain.

We can easily fix this by telling perltidy to ignore old blank lines by including the added parameter -kbl=0 and rerunning. Then the unwanted blank lines will be gone. However, this will cause all old blank lines to be ignored, perhaps even some that were added by hand to improve formatting. So please be cautious when using these parameters.

-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 except as noted above for the -blbp and -blbs parameters. 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 compatibility with previous versions.

-nsob, --noswallow-optional-blank-lines

This is equivalent to kbl=1 and is included for compatibility 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="
    

Please note that this parameter set includes -st and -se flags, which make perltidy act as a filter on one file only. These can be overridden by placing -nst and/or -nse after the -pbp parameter.

Also note that the value of continuation indentation, -ci=4, is equal to the value of the full indentation, -i=4. In some complex statements perltidy will produce nicer results with -ci=2. This can be implemented by including -ci=2 after the -pbp parameter. For example,

    # perltidy -pbp
    $self->{_text} = (
         !$section        ? ''
        : $type eq 'item' ? "the $section entry"
        :                   "the section on $section"
        )
        . (
        $page
        ? ( $section ? ' in ' : '' ) . "the $page$page_ext manpage"
        : ' elsewhere in this document'
        );
    # perltidy -pbp -ci=2
    $self->{_text} = (
         !$section        ? ''
        : $type eq 'item' ? "the $section entry"
        :                   "the section on $section"
      )
      . (
        $page
        ? ( $section ? ' in ' : '' ) . "the $page$page_ext manpage"
        : ' elsewhere in this document'
      );
    

Controlling Vertical Alignment¶

Vertical alignment refers to lining up certain symbols in list of consecutive similar lines to improve readability. For example, the "fat commas" are aligned in the following statement:

        $data = $pkg->new(
            PeerAddr => join( ".", @port[ 0 .. 3 ] ),   
            PeerPort => $port[4] * 256 + $port[5],
            Proto    => 'tcp'
        );

The only explicit control on vertical alignment is to turn it off using -novalign, a flag mainly intended for debugging. However, vertical alignment can be forced to stop and restart by selectively introducing blank lines. For example, a blank has been inserted in the following code to keep somewhat similar things aligned.

    %option_range = (
        'format'             => [ 'tidy', 'html', 'user' ],
        'output-line-ending' => [ 'dos',  'win',  'mac', 'unix' ],
        'character-encoding' => [ 'none', 'utf8' ],
        'block-brace-tightness'    => [ 0, 2 ],
        'brace-tightness'          => [ 0, 2 ],
        'paren-tightness'          => [ 0, 2 ],
        'square-bracket-tightness' => [ 0, 2 ],
    );

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 possible 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 configuration 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. Comment text begins with a #, and there must also be a space before the # for side comments. It is a good idea to put complex parameters in either single or double quotes.

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:

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 along with its opening curly brace 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-cuddled-block-list or -dcbl will dump to standard output the internal hash of cuddled block types created by a -cuddled-block-list input string.

--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.

--no-memoize or -nmem will turn of memoizing. Memoization can reduce run time when running perltidy repeatedly in a single process. It is on by default but can be deactivated for testing with -nmem.

--file-size-order or -fso will cause files to be processed in order of increasing size, when multiple files are being processed. This is useful during program development, when large numbers of files with varying sizes are processed, because it can reduce virtual memory usage.

-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.

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. To specify all blocks use '*'.

The keyword sub indicates a named sub. For anonymous subs, use the special keyword asub.

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. For another example, the following list specifies all block types for vertical tightness:

   -bbvtl='*'

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~ .