Pod::Checker(3) check pod documents for syntax errors

Other Alias

podchecker

SYNOPSIS


use Pod::Checker;
$num_errors = podchecker($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.

Curious/ambitious users are welcome to propose 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 performed:

  • 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 non-existing entities "E<...>".
  • Check for correct syntax of hyperlinks "L<...>". See perlpod 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.

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.

  • Apparent command =foo not preceded by blank line

    A command which has ended up in the middle of a paragraph or other command, such as 

      =item one
  =item two <-- bad
  • unresolved internal link NAME

    The given link to NAME does not have a matching node in the current POD. This also happened 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 =cut command

    A "=cut" command was found without a preceding POD paragraph.

  • Spurious =pod command

    A "=pod" command was found after a preceding POD paragraph.

  • 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. This warning is printed only with warning level greater than one.

  • 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 bullet-like "=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.

  • =headn without preceding higher level

    For example if there is a "=head2" in the POD file prior to a "=head1".

Hyperlinks

There are some warnings with respect to 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

See ``SYNOPSIS''

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.

Since PodParser-1.24 the Pod::Checker module uses only the poderror method to print errors and warnings. The summary output (e.g. ``Pod syntax OK'') has been dropped from the module and has been included in podchecker (the script). This allows users of Pod::Checker to control completely the output behavior. Users of podchecker (the script) get the well-known behavior.

"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->num_warnings()"
Set (if argument specified) and retrieve the number of warnings 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

Please report bugs using <http://rt.cpan.org>.

Brad Appleton <[email protected]> (initial version), Marek Rouchal <[email protected]>

Based on code for Pod::Text::pod2text() written by Tom Christiansen <[email protected]>

Pod::Checker is part of the Pod-Checker distribution, and is based on Pod::Parser.

LAST SEARCHED