Perl::Tidy(3) User Contributed Perl Documentation Perl::Tidy(3)NAMEPerl::Tidy - Parses and beautifies perl source
SYNOPSIS
use Perl::Tidy;
my $error_flag = Perl::Tidy::perltidy(
source => $source,
destination => $destination,
stderr => $stderr,
argv => $argv,
perltidyrc => $perltidyrc,
logfile => $logfile,
errorfile => $errorfile,
formatter => $formatter, # callback object (see below)
dump_options => $dump_options,
dump_options_type => $dump_options_type,
prefilter => $prefilter_coderef,
postfilter => $postfilter_coderef,
);
DESCRIPTION
This module makes the functionality of the perltidy utility available
to perl scripts. Any or all of the input parameters may be omitted, in
which case the @ARGV array will be used to provide input parameters as
described in the perltidy(1) man page.
For example, the perltidy script is basically just this:
use Perl::Tidy;
Perl::Tidy::perltidy();
The call to perltidy returns a scalar $error_flag which is TRUE if an
error caused premature termination, and FALSE if the process ran to
normal completion. Additional discuss of errors is contained below in
the ERROR HANDLING section.
The module accepts input and output streams by a variety of methods.
The following list of parameters may be any of the following: a
filename, an ARRAY reference, a SCALAR reference, or an object with
either a getline or print method, as appropriate.
source - the source of the script to be formatted
destination - the destination of the formatted output
stderr - standard error output
perltidyrc - the .perltidyrc file
logfile - the .LOG file stream, if any
errorfile - the .ERR file stream, if any
dump_options - ref to a hash to receive parameters (see below),
dump_options_type - controls contents of dump_options
dump_getopt_flags - ref to a hash to receive Getopt flags
dump_options_category - ref to a hash giving category of options
dump_abbreviations - ref to a hash giving all abbreviations
The following chart illustrates the logic used to decide how to treat a
parameter.
ref($param) $param is assumed to be:
--------------------------------
undef a filename
SCALAR ref to string
ARRAY ref to array
(other) object with getline (if source) or print method
If the parameter is an object, and the object has a close method, that
close method will be called at the end of the stream.
source
If the source parameter is given, it defines the source of the
input stream. If an input stream is defined with the source
parameter then no other source filenames may be specified in the
@ARGV array or argv parameter.
destination
If the destination parameter is given, it will be used to define
the file or memory location to receive output of perltidy.
stderr
The stderr parameter allows the calling program to redirect the
stream that would otherwise go to the standard error output device
to any of the stream types listed above. This stream contains
important warnings and errors related to the parameters passed to
perltidy.
perltidyrc
If the perltidyrc file is given, it will be used instead of any
.perltidyrc configuration file that would otherwise be used.
errorfile
The errorfile parameter allows the calling program to capture the
stream that would otherwise go to either a .ERR file. This stream
contains warnings or errors related to the contents of one source
file or stream.
The reason that this is different from the stderr stream is that
when perltidy is called to process multiple files there will be up
to one .ERR file created for each file and it would be very
confusing if they were combined.
However if perltidy is called to process just a single perl script
then it may be more conveninent to combine the errorfile stream
with the stderr stream. This can be done by setting the -se
parameter, in which case this parameter is ignored.
logfile
The logfile parameter allows the calling program to capture the
stream that would otherwise go to a .LOG file. This stream is only
created if requested with a -g parameter. It contains detailed
diagnostic information about a script which may be useful for
debugging.
argv
If the argv parameter is given, it will be used instead of the
@ARGV array. The argv parameter may be a string, a reference to a
string, or a reference to an array. If it is a string or reference
to a string, it will be parsed into an array of items just as if it
were a command line string.
dump_options
If the dump_options parameter is given, it must be the reference to
a hash. In this case, the parameters contained in any perltidyrc
configuration file will be placed in this hash and perltidy will
return immediately. This is equivalent to running perltidy with
--dump-options, except that the perameters are returned in a hash
rather than dumped to standard output. Also, by default only the
parameters in the perltidyrc file are returned, but this can be
changed (see the next parameter). This parameter provides a
convenient method for external programs to read a perltidyrc file.
An example program using this feature, perltidyrc_dump.pl, is
included in the distribution.
Any combination of the dump_ parameters may be used together.
dump_options_type
This parameter is a string which can be used to control the
parameters placed in the hash reference supplied by dump_options.
The possible values are 'perltidyrc' (default) and 'full'. The
'full' parameter causes both the default options plus any options
found in a perltidyrc file to be returned.
dump_getopt_flags
If the dump_getopt_flags parameter is given, it must be the
reference to a hash. This hash will receive all of the parameters
that perltidy understands and flags that are passed to
Getopt::Long. This parameter may be used alone or with the
dump_options flag. Perltidy will exit immediately after filling
this hash. See the demo program perltidyrc_dump.pl for example
usage.
dump_options_category
If the dump_options_category parameter is given, it must be the
reference to a hash. This hash will receive a hash with keys equal
to all long parameter names and values equal to the title of the
corresponding section of the perltidy manual. See the demo program
perltidyrc_dump.pl for example usage.
dump_abbreviations
If the dump_abbreviations parameter is given, it must be the
reference to a hash. This hash will receive all abbreviations used
by Perl::Tidy. See the demo program perltidyrc_dump.pl for example
usage.
prefilter
A code reference that will be applied to the source before tidying.
It is expected to take the full content as a string in its input,
and output the transformed content.
postfilter
A code reference that will be applied to the tidied result before
outputting. It is expected to take the full content as a string in
its input, and output the transformed content.
Note: A convenient way to check the function of your custom
prefilter and postfilter code is to use the --notidy option, first
with just the prefilter and then with both the prefilter and
postfilter. See also the file filter_example.pl in the perltidy
distribution.
ERROR HANDLING
Perltidy will return with an error flag indicating if the process had
to be terminated early due to errors in the input parameters. This can
happen for example if a parameter is misspelled or given an invalid
value. The calling program should check this flag because if it is set
the destination stream will be empty or incomplete and should be
ignored. Error messages in the stderr stream will indicate the cause
of any problem.
If the error flag is not set then perltidy ran to completion. However
there may still be warning messages in the stderr stream related to
control parameters, and there may be warning messages in the errorfile
stream relating to possible syntax errors in the source code being
tidied.
In the event of a catastrophic error for which recovery is not possible
perltidy terminates by making calls to croak or confess to help the
programmer localize the problem. These should normally only occur
during program development.
NOTES ON FORMATTING PARAMETERS
Parameters which control formatting may be passed in several ways: in a
.perltidyrc configuration file, in the perltidyrc parameter, and in the
argv parameter.
The -syn (--check-syntax) flag may be used with all source and
destination streams except for standard input and output. However data
streams which are not associated with a filename will be copied to a
temporary file before being be passed to Perl. This use of temporary
files can cause somewhat confusing output from Perl.
If the -pbp style is used it will typically be necessary to also
specify a -nst flag. This is necessary to turn off the -st flag
contained in the -pbp parameter set which otherwise would direct the
output stream to the standard output.
EXAMPLES
The following example uses string references to hold the input and
output code and error streams, and illustrates checking for errors.
use Perl::Tidy;
my $source_string = <<'EOT';
my$error=Perl::Tidy::perltidy(argv=>$argv,source=>\$source_string,
destination=>\$dest_string,stderr=>\$stderr_string,
errorfile=>\$errorfile_string,);
EOT
my $dest_string;
my $stderr_string;
my $errorfile_string;
my $argv = "-npro"; # Ignore any .perltidyrc at this site
$argv .= " -pbp"; # Format according to perl best practices
$argv .= " -nst"; # Must turn off -st in case -pbp is specified
$argv .= " -se"; # -se appends the errorfile to stderr
## $argv .= " --spell-check"; # uncomment to trigger an error
print "<<RAW SOURCE>>\n$source_string\n";
my $error = Perl::Tidy::perltidy(
argv => $argv,
source => \$source_string,
destination => \$dest_string,
stderr => \$stderr_string,
errorfile => \$errorfile_string, # ignored when -se flag is set
##phasers => 'stun', # uncomment to trigger an error
);
if ($error) {
# serious error in input parameters, no tidied output
print "<<STDERR>>\n$stderr_string\n";
die "Exiting because of serious errors\n";
}
if ($dest_string) { print "<<TIDIED SOURCE>>\n$dest_string\n" }
if ($stderr_string) { print "<<STDERR>>\n$stderr_string\n" }
if ($errorfile_string) { print "<<.ERR file>>\n$errorfile_string\n" }
Additional examples are given in examples section of the perltidy
distribution.
Using the formatter Callback Object
The formatter parameter is an optional callback object which allows the
calling program to receive tokenized lines directly from perltidy for
further specialized processing. When this parameter is used, the two
formatting options which are built into perltidy (beautification or
html) are ignored. The following diagram illustrates the logical flow:
|-- (normal route) -> code beautification
caller->perltidy->|-- (-html flag ) -> create html
|-- (formatter given)-> callback to write_line
This can be useful for processing perl scripts in some way. The
parameter $formatter in the perltidy call,
formatter => $formatter,
is an object created by the caller with a "write_line" method which
will accept and process tokenized lines, one line per call. Here is a
simple example of a "write_line" which merely prints the line number,
the line type (as determined by perltidy), and the text of the line:
sub write_line {
# This is called from perltidy line-by-line
my $self = shift;
my $line_of_tokens = shift;
my $line_type = $line_of_tokens->{_line_type};
my $input_line_number = $line_of_tokens->{_line_number};
my $input_line = $line_of_tokens->{_line_text};
print "$input_line_number:$line_type:$input_line";
}
The complete program, perllinetype, is contained in the examples
section of the source distribution. As this example shows, the
callback method receives a parameter $line_of_tokens, which is a
reference to a hash of other useful information. This example uses
these hash entries:
$line_of_tokens->{_line_number} - the line number (1,2,...)
$line_of_tokens->{_line_text} - the text of the line
$line_of_tokens->{_line_type} - the type of the line, one of:
SYSTEM - system-specific code before hash-bang line
CODE - line of perl code (including comments)
POD_START - line starting pod, such as '=head'
POD - pod documentation text
POD_END - last line of pod section, '=cut'
HERE - text of here-document
HERE_END - last line of here-doc (target word)
FORMAT - format section
FORMAT_END - last line of format section, '.'
DATA_START - __DATA__ line
DATA - unidentified text following __DATA__
END_START - __END__ line
END - unidentified text following __END__
ERROR - we are in big trouble, probably not a perl script
Most applications will be only interested in lines of type CODE. For
another example, let's write a program which checks for one of the so-
called naughty matching variables "&`", $&, and "$'", which can slow
down processing. Here is a write_line, from the example program
find_naughty.pl, which does that:
sub write_line {
# This is called back from perltidy line-by-line
# We're looking for $`, $&, and $'
my ( $self, $line_of_tokens ) = @_;
# pull out some stuff we might need
my $line_type = $line_of_tokens->{_line_type};
my $input_line_number = $line_of_tokens->{_line_number};
my $input_line = $line_of_tokens->{_line_text};
my $rtoken_type = $line_of_tokens->{_rtoken_type};
my $rtokens = $line_of_tokens->{_rtokens};
chomp $input_line;
# skip comments, pod, etc
return if ( $line_type ne 'CODE' );
# loop over tokens looking for $`, $&, and $'
for ( my $j = 0 ; $j < @$rtoken_type ; $j++ ) {
# we only want to examine token types 'i' (identifier)
next unless $$rtoken_type[$j] eq 'i';
# pull out the actual token text
my $token = $$rtokens[$j];
# and check it
if ( $token =~ /^\$[\`\&\']$/ ) {
print STDERR
"$input_line_number: $token\n";
}
}
}
This example pulls out these tokenization variables from the
$line_of_tokens hash reference:
$rtoken_type = $line_of_tokens->{_rtoken_type};
$rtokens = $line_of_tokens->{_rtokens};
The variable $rtoken_type is a reference to an array of token type
codes, and $rtokens is a reference to a corresponding array of token
text. These are obviously only defined for lines of type CODE.
Perltidy classifies tokens into types, and has a brief code for each
type. You can get a complete list at any time by running perltidy from
the command line with
perltidy --dump-token-types
In the present example, we are only looking for tokens of type i
(identifiers), so the for loop skips past all other types. When an
identifier is found, its actual text is checked to see if it is one
being sought. If so, the above write_line prints the token and its
line number.
The formatter feature is relatively new in perltidy, and further
documentation needs to be written to complete its description.
However, several example programs have been written and can be found in
the examples section of the source distribution. Probably the best way
to get started is to find one of the examples which most closely
matches your application and start modifying it.
For help with perltidy's pecular way of breaking lines into tokens, you
might run, from the command line,
perltidy -D filename
where filename is a short script of interest. This will produce
filename.DEBUG with interleaved lines of text and their token types.
The -D flag has been in perltidy from the beginning for this purpose.
If you want to see the code which creates this file, it is
"write_debug_entry" in Tidy.pm.
EXPORT
&perltidy
CREDITS
Thanks to Hugh Myers who developed the initial modular interface to
perltidy.
VERSION
This man page documents Perl::Tidy version 20121207.
LICENSE
This package is free software; you can redistribute it and/or modify it
under the terms of the "GNU General Public License".
Please refer to the file "COPYING" for details.
AUTHOR
Steve Hancock
perltidy at users.sourceforge.net
SEE ALSO
The perltidy(1) man page describes all of the features of perltidy. It
can be found at http://perltidy.sourceforge.net.
perl v5.16.2 2012-12-08 Perl::Tidy(3)
