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Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)


CentOS 2.1AS







Pod::Checker, podchecker() − check pod documents for syntax errors


  use Pod::Checker;
  $syntax_okay = podchecker($filepath, $outputpath, %options);

  my $checker = new Pod::Checker %options;
  $checker->parse_from_file($filepath, \*STDERR);


"$filepath" is the input POD to read and "$outputpath" is where to write POD syntax error messages. Either argument may be a scalar indicating a file-path, or else a reference to an open filehandle. If unspecified, the input-file it defaults to "\*STDIN", and the output-file defaults to "\*STDERR".


This function can take a hash of options:
=> val

Turn warnings on/off. val is usually 1 for on, but higher values trigger additional warnings. See the section on "Warnings".


podchecker will perform syntax checking of Perl5 POD format documentation.


It is hoped that curious/ambitious user will help flesh out and add the additional features they wish to see in Pod::Checker and podchecker and verify that the checks are consistent with the perlpod manpage.

The following checks are currently preformed:

Unknown ’=xxxx’ commands, unknown ’X<...>’ interior-sequences, and unterminated interior sequences.

Check for proper balancing of "=begin" and "=end". The contents of such a block are generally ignored, i.e. no syntax checks are performed.

Check for proper nesting and balancing of "=over", "=item" and "=back".

Check for same nested interior-sequences (e.g. "L<...L<...>...>").

Check for malformed or nonexisting entities "E<...>".

Check for correct syntax of hyperlinks "L<...>". See the perlpod manpage for details.

Check for unresolved document-internal links. This check may also reveal misspelled links that seem to be internal links but should be links to something else.


• empty =headn

A heading ("=head1" or "=head2") without any text? That ain’t no heading!

• =over on line N without closing =back

The "=over" command does not have a corresponding "=back" before the next heading ("=head1" or "=head2") or the end of the file.

• =item without previous =over
• =back without previous =over

An "=item" or "=back" command has been found outside a "=over"/"=back" block.

• No argument for =begin

A "=begin" command was found that is not followed by the formatter specification.

• =end without =begin

A standalone "=end" command was found.

• Nested =begin’s

There were at least two consecutive "=begin" commands without the corresponding "=end". Only one "=begin" may be active at a time.

• =for without formatter specification

There is no specification of the formatter after the "=for" command.

• unresolved internal link NAME

The given link to NAME does not have a matching node in the current POD . This also happend when a single word node name is not enclosed in """".

• Unknown command "" CMD ""

An invalid POD command has been found. Valid are "=head1", "=head2", "=over", "=item", "=back", "=begin", "=end", "=for", "=pod", "=cut"

• Unknown interior-sequence "" SEQ ""

An invalid markup command has been encountered. Valid are: "B<>", "C<>", "E<>", "F<>", "I<>", "L<>", "S<>", "X<>", "Z<>"

• nested commands CMD <... CMD <...>...>

Two nested identical markup commands have been found. Generally this does not make sense.

• garbled entity STRING

The STRING found cannot be interpreted as a character entity.

• Entity number out of range

An entity specified by number (dec, hex, oct) is out of range (1−255).

• malformed link L<>

The link found cannot be parsed because it does not conform to the syntax described in the perlpod manpage.

• nonempty Z<>

The "Z<>" sequence is supposed to be empty.

• empty X<>

The index entry specified contains nothing but whitespace.

• Spurious text after =pod / =cut

The commands "=pod" and "=cut" do not take any arguments.

• Spurious character(s) after =back

The "=back" command does not take any arguments.


These may not necessarily cause trouble, but indicate mediocre style.
• multiple occurence of link target name

The POD file has some "=item" and/or "=head" commands that have the same text. Potential hyperlinks to such a text cannot be unique then.

• line containing nothing but whitespace in paragraph

There is some whitespace on a seemingly empty line. POD is very sensitive to such things, so this is flagged. vi users switch on the list option to avoid this problem.

• previous =item has no contents

There is a list "=item" right above the flagged line that has no text contents. You probably want to delete empty items.

• preceding non-item paragraph(s)

A list introduced by "=over" starts with a text or verbatim paragraph, but continues with "=item"s. Move the non-item paragraph out of the "=over"/"=back" block.

• =item type mismatch (one vs. two)

A list started with e.g. a bulletted "=item" and continued with a numbered one. This is obviously inconsistent. For most translators the type of the first "=item" determines the type of the list.

N unescaped ""<>"" in paragraph

Angle brackets not written as "<lt>" and "<gt>" can potentially cause errors as they could be misinterpreted as markup commands. This is only printed when the −warnings level is greater than 1.

• Unknown entity

A character entity was found that does not belong to the standard ISO set or the POD specials "verbar" and "sol".

• No items in =over

The list opened with "=over" does not contain any items.

• No argument for =item

"=item" without any parameters is deprecated. It should either be followed by "*" to indicate an unordered list, by a number (optionally followed by a dot) to indicate an ordered (numbered) list or simple text for a definition list.

• empty section in previous paragraph

The previous section (introduced by a "=head" command) does not contain any text. This usually indicates that something is missing. Note: A "=head1" followed immediately by "=head2" does not trigger this warning.

• Verbatim paragraph in NAME section

The NAME section ("=head1 NAME") should consist of a single paragraph with the script/module name, followed by a dash ’−’ and a very short description of what the thing is good for.


There are some warnings wrt. malformed hyperlinks.
• ignoring leading/trailing whitespace in link

There is whitespace at the beginning or the end of the contents of L<...>.

• (section) in ’$page’ deprecated

There is a section detected in the page name of L<...>, e.g. "L>passwd(2)>". POD hyperlinks may point to POD documents only. Please write "C<passwd(2)>" instead. Some formatters are able to expand this to appropriate code. For links to (builtin) functions, please say "L<perlfunc/mkdir>", without ().

• alternative text/node ’%s’ contains non-escaped ⎪ or /

The characters "⎪" and "/" are special in the L<...> context. Although the hyperlink parser does its best to determine which "/" is text and which is a delimiter in case of doubt, one ought to escape these literal characters like this:

  /     E<sol>
  ⎪     E<verbar>


podchecker returns the number of POD syntax errors found or −1 if there were no POD commands at all found in the file.




While checking, this module collects document properties, e.g. the nodes for hyperlinks ("=headX", "=item") and index entries ("X<>"). POD translators can use this feature to syntax-check and get the nodes in a first pass before actually starting to convert. This is expensive in terms of execution time, but allows for very robust conversions.
""Pod::Checker−>new( %options )""

Return a reference to a new Pod::Checker object that inherits from Pod::Parser and is used for calling the required methods later. The following options are recognized:

"−warnings => num"
Print warnings if "num" is true. The higher the value of "num", the more warnings are printed. Currently there are only levels 1 and 2.

"−quiet => num"
If "num" is true, do not print any errors/warnings. This is useful when Pod::Checker is used to munge POD code into plain text from within POD formatters.

""$checker−>poderror( @args )""
""$checker−>poderror( {%opts}, @args )""

Internal method for printing errors and warnings. If no options are given, simply prints "@_". The following options are recognized and used to form the output:


A message to print prior to "@args".


The line number the error occurred in.


The file (name) the error occurred in.


The error level, should be ’ WARNING ’ or ’ ERROR ’.


Set (if argument specified) and retrieve the number of errors found.


Set (if argument specified) and retrieve the canonical name of POD as found in the "=head1 NAME" section.


Add (if argument specified) and retrieve the nodes (as defined by "=headX" and "=item") of the current POD . The nodes are returned in the order of their occurence. They consist of plain text, each piece of whitespace is collapsed to a single blank.


Add (if argument specified) and retrieve the index entries (as defined by "X<>") of the current POD . They consist of plain text, each piece of whitespace is collapsed to a single blank.


Add (if argument specified) and retrieve the hyperlinks (as defined by "L<>") of the current POD . They consist of an 2−item array: line number and "Pod::Hyperlink" object.


Brad Appleton <bradapp@enteract.com> (initial version), Marek Rouchal <marek@saftsack.fs.uni-bayreuth.de>

Based on code for Pod::Text::pod2text() written by Tom Christiansen <tchrist@mox.perl.com>