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Perl::Critic and Perl::Tidy. Your guide to better programming practices. What is Perl::Tidy and Perl::Critic?. www.thedailywtf.com. What is Perl::Tidy and Perl::Critic?. Perl::Tidy a script which indents and reformats Perl code to make it easier to read. - PowerPoint PPT Presentation
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Perl::Critic and Perl::Tidy
Your guide to better programming practices.
What is Perl::Tidy and Perl::Critic?
www.thedailywtf.com
What is Perl::Tidy and Perl::Critic?
• Perl::Tidy a script which indents and reformats Perl code to make it easier to read.
• Perl::Critic is basically a source code analyzer, that applies best practices to your code.
Perl::Tidy• Take the following code:if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /Some_other_test/i ) {
my $code="here";
if($var >=1 && $var <= 5 )
{
my $other_code = "here";
}
else { my $other_code = "here";
}
}
Perl::Tidy• Take the following code:if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /Some_other_test/i ) {
my $code="here";
if($var >=1 && $var <= 5 )
{
my $other_code = "here";
}
else { my $other_code = "here";
}
}
PRETTY UGLY HUH?
Lets see what Perl::Tidy can do!
Perl::Tidy• Default Perl::Critic behavior:if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /\[Some_other_test\]/i )
{
my $code = "here";
if ( $var >= 1 && $var <= 5 ) {
my $other_code = "here";
}
else {
my $other_code = "here";
}
}
Perl::Tidy• For most individuals the default
behavior is good enough
Perl::Tidy• For most individuals the default
behavior is good enough
• However some groups of coders have certain coding standards that are different from the default perl::Critic behavior
Perl::Tidy• Take the following code:if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /Some_other_test/i ) {
my $code="here";
if($var >=1 && $var <= 5 )
{
my $other_code = "here";
}
else { my $other_code = "here";
}
}
Perl::Tidy• Perltidy -ce # (Cuddled Elses)if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /\[Some_other_test\]/i )
{
my $code = "here";
if ( $var >= 1 && $var <= 5 ) {
my $other_code = "here";
} else {
my $other_code = "here";
}
}
Perl::Tidy• You can change the indenting level with -i=n• This is -i=2if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /\[Some_other_test\]/i )
{
my $code = "here";
if ( $var >= 1 && $var <= 5 ) {
my $other_code = "here";
}
else {
my $other_code = "here";
}
}
Perl::Tidy• You can change the indenting level with -i=n• This is -i=20
if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /\[Some_other_test\]/i )
{
my $code = "here";
if ( $var >= 1 && $var <= 5 ) {
my $other_code = "here";
}
else {
my $other_code = "here";
}
}
Perl::Tidy• You can have the opening braces on the left:• This is -blif ( $toOrCC =~ /(sometest)/i || $subject =~ /\[Some_other_test\]/i ){ my $code = "here"; if ( $var >= 1 && $var <= 5 ) { my $other_code = "here"; } else { my $other_code = "here"; }}
Perl::Tidy• You can have the opening braces on the left:• This is -bliif ( $toOrCC =~ /(sometest)/i || $subject =~ /\[Some_other_test\]/i ) { my $code = "here"; if ( $var >= 1 && $var <= 5 ) { my $other_code = "here"; } else { my $other_code = "here"; } }
Perl::Tidy• Another formatting option:• This is -bli -i=2
if ( $toOrCC =~ /(sometest)/i
|| $subject =~ /\[Some_other_test\]/i )
{
my $code = "here";
if ( $var >= 1 && $var <= 5 )
{
my $other_code = "here";
}
else
{
my $other_code = "here";
}
}
Perl::Tidy• Continuation Indentation• -ci=14
Changes :my $filename = $home_dir."/".$username."/".$projectfile."/".$file;
To:my $filename =
$home_dir . "/"
. $username . "/"
. $projectfile . "/”
. $file;
Uses the line length variable set with -l=n
Perl::Tidy• ~/.perltidyrc• All the options of perltidy can be put into a config file• One option per line• # is a comment line • My conf file is two lines:-i=4 # indent 4
-bli # new blocks get a new line and are indented
• Ignore the config file with -npro or set a different config file with-pro=filename
Perl::Tidy• Other formatting options can be researched at
http://perltidy.sourceforge.net/stylekey.html• -ole=s specify output line ending (s=dos or win, mac, unix)• -o=file name of the output file (only if single input file)• -oext=s change output extension from 'tdy' to s• -opath=path change path to be 'path' for output files• -b backup original to .bak and modify file in-place• -bext=s change default backup extension from 'bak' to s• -q deactivate error messages (for running under editor)• -w include non-critical warning messages in the .ERR error
output• -syn run perl -c to check syntax (default under unix systems)• -log save .LOG file, which has useful diagnostics
Perl::TidyOther formatting options can be researched at
http://perltidy.sourceforge.net/stylekey.html -f force perltidy to read a binary file• -g like -log but writes more detailed .LOG file, for debugging
scripts
• -opt write the set of options actually used to a .LOG file• -st send output to standard output, STDOUT• -se send error output to standard error output, STDERR• -v display version number to standard output and quit
Perl::Critic
• What is it,
• What is it good for?
Perl::Critic
• Help you find in order of severity from highest to lowest:– Bugs– Bad practices– Cases where you are not complying with
common style practices– Readability issues
• Perl::Critic Rates violations from 1 to 5 with five being the most serious violations
Perl::Critic
How it works:% perlcritic goodcode.pl goodcode.pl source OK
% perlcritic badcode.plCode before strictures are enabled at line 4,
column 1. See page 429 of PBP. (Severity: 5)
Perl::Critic
Perl::Critic options/features:• Default severity is 5, you can change it with the
flag -n where n=1..5
Perl::Critic
Perl::Critic options/features:• Default severity is 5, you can change it with the
flag -n where n=1..5• -top 7 will show you the top 7 code violations
Perl::Critic
Perl::Critic options/features:• Default severity is 5, you can change it with the
flag -n where n=1..5• -top 7 will show you the top 7 code violations• ~/.perlcriticrc
– Change severity of policies• [ControlStructures::ProhibitPostfixControls] severity = cruel # Same as "severity = 2”
– Change dis/allowed policies:• [ControlStructures::ProhibitPostfixControls] allow = if unless
Perl::Critic
Perl::Critic options/features:• ~/.perlcriticrc• Turn off specific policies:
[-NamingConventions::ProhibitMixedCaseVars] [-NamingConventions::ProhibitMixedCaseSubs]
Perl::Critic
Perl::Critic options/features:• Turn off Perl::Critic for a single line:
– open(FILE,”>$path”); ## no critic• Turn off Perl::Critic for a block:
– ## no critic– open(FILE,”>$path”);– ## use critic
Perl::Critic
Perl::Critic options/features:• Turn off a specific policy for a single line:
– $email = ‘[email protected]’ ## no critic(RequireInterpolation)
• Turn off A specific policy for a function or block of code:– sub complex_fcn { ## no critic(ExcessComplexity)
… some complex code
}
Perl::Critic
• You can create a ‘.t’ file to run as you ‘make test’,• Just don’t upload that test to CPAN
Perl::Critic and Perl::Tidy
• Any Questions?
• More info:– http://search.cpan.org/~elliotjs/Perl-Critic-1.080/lib/Perl/Critic.pm– http://search.cpan.org/~shancock/Perl-Tidy-20071205/lib/Perl/Tidy.
pm
