NAME

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

SYNOPSIS

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

OPTIONS/ARGUMENTS

$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.

podchecker()

This function can take a hash of options:

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

DESCRIPTION

podchecker will perform syntax checking of Perl5 POD format documentation.

NOTE THAT THIS MODULE IS CURRENTLY IN THE BETA STAGE!

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 perlpod.

The following checks are currently preformed:

DIAGNOSTICS

Errors

* 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, =head3, =head4, =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 perlpod.
* 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.

Warnings

These may not necessarily cause trouble, but indicate mediocre style.

* multiple occurrence 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 =items. 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.

Hyperlinks

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>

RETURN VALUE

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

EXAMPLES

[T.B.D.]

INTERFACE

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:

  -msg

A message to print prior to @args.

  -line

The line number the error occurred in.

  -file

The file (name) the error occurred in.

  -severity

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

$checker->num_errors()

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

$checker->name()

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

$checker->node()

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 occurrence. They consist of plain text, each piece of whitespace is collapsed to a single blank.

$checker->idx()

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.

$checker->hyperlink()
Add (if argument specified) and retrieve the hyperlinks (as defined by L<>) of the current POD. They consist of a 2-item array: line number and Pod::Hyperlink object.

AUTHOR

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>