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$s = <<'EOF';
<head>
<title>perl_checker</title>
<style> body { max-width: 900; } </style>
</head>
<h1>Quick Start</h1>
To use perl_checker, simply use "perl_checker a_file.pl"
<p>
To use under emacs, simply add the following line to your .emacs,
then when you visit a perl file, you can use Ctrl-Return to run perl_checker
on this file
<pre>
(global-set-key [(control return)] (lambda () (interactive) (save-some-buffers 1) (compile (concat "perl_checker --restrict-to-files " (buffer-file-name (current-buffer))))))
</pre>
<p>
To use with vim, use something like:
<pre>
perl_checker --restrict-to-files scanner.pm > errors.err ; vim -c ':copen 4' -c ':so /usr/share/vim/ftplugin/perl_checker.vim' -q
</pre>
where /usr/share/vim/ftplugin/perl_checker.vim is
<pre>
" Error formats
setlocal efm=
\%EFile\ \"%f\"\\,\ line\ %l\\,\ characters\ %c-%*\\d:,
\%EFile\ \"%f\"\\,\ line\ %l\\,\ character\ %c:%m,
\%+EReference\ to\ unbound\ regexp\ name\ %m,
\%Eocamlyacc:\ e\ -\ line\ %l\ of\ \"%f\"\\,\ %m,
\%Wocamlyacc:\ w\ -\ %m,
\%-Zmake%.%#,
\%C%m
</pre>
<h1>Goals of perl_checker</h1>
<ul>
<li> for beginners in perl:
based on what the programmer is writing,
<ul>
<li> suggest better or more standard ways to do the same
<li> detect wrong code
<br>
=> a kind of automatic teacher
</ul>
<li> for senior programmers:
detect typos, unused variables, check number
of parameters, global analysis to check method calls...
<li> enforce the same perl style by enforcing a subset of perl of features.
In perl <a href="http://c2.com/cgi/wiki?ThereIsMoreThanOneWayToDoIt">There is more than one way to do it</a>.
In perl_checker's subset of Perl, there is not too many ways to do it.
This is especially useful for big projects.
(NB: the subset is chosen to keep a good expressivity)
</ul>
<h1>Compared to <a href="http://www.perl.com/pub/a/2005/06/09/ppi.html">PPI</a> and <a href="http://perlcritic.tigris.org/">Perl-Critic</a></h1>
<ul>
<li>perl_checker use its own OCaml-written parser.
This parser only handle a subset of perl,
whereas one of PPI's goal is to be able to parse non finished perl documents.
<p>perl_checker is a checker: it is not a big deal to die horribly on a weird perl expression, it tells the programmer what to write instead.
The issue is that perl_checker includes inter-modules analysis, and it implies being able to parse non-perl_checker compliant modules.
A solution for this is perl_checker <i>fake</i> modules. No perfect solution though.
<li>PPI doesn't handle operator priorities: <tt>1 + 2 << 3</tt> is parsed as
<ul><li>PPI: a list [ Number(<tt>1</tt>), Operator(<tt>+</tt>), Number(<tt>2</tt>), Operator(<tt><<</tt>), Number(<tt>3</tt>) ]
<li>perl_checker: a tree Operator(<tt><<</tt>, [ Operator(<tt>+</tt>, [ Number(<tt>1</tt>), Number(<tt>2</tt>) ]), Number(<tt>3</tt>) ])
</ul>
This limits perlcritic checks to a syntax level.
<li>perl_checker is <b>much</b> faster (more than 100 times) (ML pattern matching rulez)
<li>perl_checker checks a lot more things than perlcritic: undeclared variables, unknown functions, unknown methods...
<li>and of course perl_checker checks are different from the Conways's <a href="http://www.oreilly.com/catalog/perlbp/">Perl Best Practices</a>
</ul>
<h1>Get it</h1>
<a href="http://svnweb.mageia.org/packages/cauldron/perl_checker/current/SOURCES/">tarball</a>
<br>
<a href="http://svnweb.mageia.org/soft/perl_checker/">SVN source</a>
<br>
<a href="http://svnweb.mageia.org/packages/cauldron/perl-MDK-Common/current/SOURCES/">MDK::Common tarball</a>
<h1>Implemented features</h1>
<dl>
<dt>detect some Perl traps
<dd>some Perl expressions are stupid, and one gets a warning when running
them with <tt>perl -w</tt>. The drawback of <tt>perl -w</tt> is the lack of
code coverage, it only detects expressions which are evaluated.
TESTS=various_errors.t
</dd>
<dt>context checks
<dd>Perl has types associated with variables names, the so-called "context".
Some expressions mixing contexts are stupid, perl_checker detects them.
TESTS=context.t
</dd>
<dt>suggest simpler expressions
<dd>when there is a simpler way to write an expression, suggest it. It can
also help detecting errors.
TESTS=suggest_better.t
</dd>
<dt>function call check
<dd>detection of unknown functions or mismatching prototypes (warning: since
perl is a dynamic language, some spurious warnings may occur when a function
is defined using stashes).
TESTS=prototype.t
</dd>
<dt>method call check
<dd>detection of unknown methods or mismatching prototypes. perl_checker
doesn't have any idea what the object type is, it simply checks if a method
with that name and that number of parameters exists.
TESTS=method.t
</dd>
<dt>return value check
<dd>dropping the result of a functionnally <i>pure</i> function is stupid.
using the result of a function returning void is stupid too.
<br>(nb: perl_checker enforces <tt>&&</tt> and <tt>||</tt> are used as boolean operators
whereas <tt>and</tt> and <tt>or</tt> are used for control flow)
TESTS=return_value.t
</dd>
<dt>white space normalization
<dd>enforce a similar coding style. In many languages you can find a coding
style document (eg: <a href="http://www.gnu.org/prep/standards/standards.html#Writing-C">the GNU one</a>).
TESTS=force_layout.t
</dd>
<dt>disallow <i>complex</i> expressions
<dd>perl_checker try to ban some weird-not-used-a-lot features.
TESTS=syntax_restrictions.t
</dd>
</dl>
<h1>Todo</h1>
Functionalities that would be nice:
<ul>
<li> add flow analysis
<li> maybe a "soft typing" type analysis
<li> detect places where imperative code can be replaced with
functional code (already done for some <b>simple</b> loops)
<li> check the number of returned values when checking prototype compliance
</ul>
EOF
my $_rationale = <<'EOF';
<h1>Rationale</h1>
Perl is a big language, there is <a
href="http://c2.com/cgi/wiki?ThereIsMoreThanOneWayToDoIt">ThereIsMoreThanOneWayToDoIt</a>.
It has advantages but also some drawbacks for team project:
<ul>
<li> it is hard to learn every special rules. Automatically enforced syntax
coding rules help learning incrementally
EOF
use lib ('test', '..');
use read_t;
sub get_example {
my ($file) = @_;
my @tests = read_t::read_t("test/$file");
$file =~ s|test/||;
qq(<p><a name="$file"><table border=1 cellpadding=3>\n) .
join('', map {
my $lines = join("<br>", map { "<tt>" . html_quote($_) . "</tt>" } @{$_->{lines}});
my $logs = join("<br>", map { html_quote($_) } @{$_->{logs}});
$logs ? " <tr><td>\n" . $lines . "</td><td>" . $logs . "</td></tr>\n" : '';
} @tests) .
"</table></a>\n";
}
sub anchor_to_examples {
my ($s) = @_;
$s =~ s!TESTS=(\S+)!(<a href="#$1">examples</a>)!g;
$s;
}
sub fill_in_examples {
my ($s) = @_;
$s =~ s!TESTS=(\S+)!get_example($1)!ge;
$s;
}
$s =~ s!<h1>Implemented features</h1>(.*)<h1>!
"<h1>Implemented features</h1>" . anchor_to_examples($1) .
"<h1>Examples</h1>" . fill_in_examples($1) .
"<h1>"!se;
print $s;
sub html_quote {
local $_ = $_[0];
s/</</g;
s/>/>/g;
s/^(\s*)/" " x length($1)/e;
$_;
}
|
