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  1. =head1 NAME
  2. perlpod - plain old documentation
  3. =head1 DESCRIPTION
  4. A pod-to-whatever translator reads a pod file paragraph by paragraph,
  5. and translates it to the appropriate output format. There are
  6. three kinds of paragraphs:
  7. L<verbatim|/"Verbatim Paragraph">,
  8. L<command|/"Command Paragraph">, and
  9. L<ordinary text|/"Ordinary Block of Text">.
  10. =head2 Verbatim Paragraph
  11. A verbatim paragraph, distinguished by being indented (that is,
  12. it starts with space or tab). It should be reproduced exactly,
  13. with tabs assumed to be on 8-column boundaries. There are no
  14. special formatting escapes, so you can't italicize or anything
  15. like that. A \ means \, and nothing else.
  16. =head2 Command Paragraph
  17. All command paragraphs start with "=", followed by an
  18. identifier, followed by arbitrary text that the command can
  19. use however it pleases. Currently recognized commands are
  20. =head1 heading
  21. =head2 heading
  22. =item text
  23. =over N
  24. =back
  25. =cut
  26. =pod
  27. =for X
  28. =begin X
  29. =end X
  30. =over 4
  31. =item =pod
  32. =item =cut
  33. The "=pod" directive does nothing beyond telling the compiler to lay
  34. off parsing code through the next "=cut". It's useful for adding
  35. another paragraph to the doc if you're mixing up code and pod a lot.
  36. =item =head1
  37. =item =head2
  38. Head1 and head2 produce first and second level headings, with the text in
  39. the same paragraph as the "=headn" directive forming the heading description.
  40. =item =over
  41. =item =back
  42. =item =item
  43. Item, over, and back require a little more explanation: "=over" starts a
  44. section specifically for the generation of a list using "=item" commands. At
  45. the end of your list, use "=back" to end it. You will probably want to give
  46. "4" as the number to "=over", as some formatters will use this for indentation.
  47. This should probably be a default. Note also that there are some basic rules
  48. to using =item: don't use them outside of an =over/=back block, use at least
  49. one inside an =over/=back block, you don't _have_ to include the =back if
  50. the list just runs off the document, and perhaps most importantly, keep the
  51. items consistent: either use "=item *" for all of them, to produce bullets,
  52. or use "=item 1.", "=item 2.", etc., to produce numbered lists, or use
  53. "=item foo", "=item bar", etc., i.e., things that looks nothing like bullets
  54. or numbers. If you start with bullets or numbers, stick with them, as many
  55. formatters use the first "=item" type to decide how to format the list.
  56. =item =for
  57. =item =begin
  58. =item =end
  59. For, begin, and end let you include sections that are not interpreted
  60. as pod text, but passed directly to particular formatters. A formatter
  61. that can utilize that format will use the section, otherwise it will be
  62. completely ignored. The directive "=for" specifies that the entire next
  63. paragraph is in the format indicated by the first word after
  64. "=for", like this:
  65. =for html <br>
  66. <p> This is a raw HTML paragraph </p>
  67. The paired commands "=begin" and "=end" work very similarly to "=for", but
  68. instead of only accepting a single paragraph, all text from "=begin" to a
  69. paragraph with a matching "=end" are treated as a particular format.
  70. Here are some examples of how to use these:
  71. =begin html
  72. <br>Figure 1.<IMG SRC="figure1.png"><br>
  73. =end html
  74. =begin text
  75. ---------------
  76. | foo |
  77. | bar |
  78. ---------------
  79. ^^^^ Figure 1. ^^^^
  80. =end text
  81. Some format names that formatters currently are known to accept include
  82. "roff", "man", "latex", "tex", "text", and "html". (Some formatters will
  83. treat some of these as synonyms.)
  84. And don't forget, when using any command, that the command lasts up until
  85. the end of the B<paragraph>, not the line. Hence in the examples below, you
  86. can see the empty lines after each command to end its paragraph.
  87. Some examples of lists include:
  88. =over 4
  89. =item *
  90. First item
  91. =item *
  92. Second item
  93. =back
  94. =over 4
  95. =item Foo()
  96. Description of Foo function
  97. =item Bar()
  98. Description of Bar function
  99. =back
  100. =back
  101. =head2 Ordinary Block of Text
  102. It will be filled, and maybe even
  103. justified. Certain interior sequences are recognized both
  104. here and in commands:
  105. I<text> italicize text, used for emphasis or variables
  106. B<text> embolden text, used for switches and programs
  107. S<text> text contains non-breaking spaces
  108. C<code> literal code
  109. L<name> A link (cross reference) to name
  110. L<name> manual page
  111. L<name/ident> item in manual page
  112. L<name/"sec"> section in other manual page
  113. L<"sec"> section in this manual page
  114. (the quotes are optional)
  115. L</"sec"> ditto
  116. same as above but only 'text' is used for output.
  117. (Text can not contain the characters '/' and '|',
  118. and should contain matched '<' or '>')
  119. L<text|name>
  120. L<text|name/ident>
  121. L<text|name/"sec">
  122. L<text|"sec">
  123. L<text|/"sec">
  124. F<file> Used for filenames
  125. X<index> An index entry
  126. Z<> A zero-width character
  127. E<escape> A named character (very similar to HTML escapes)
  128. E<lt> A literal <
  129. E<gt> A literal >
  130. E<sol> A literal /
  131. E<verbar> A literal |
  132. (these are optional except in other interior
  133. sequences and when preceded by a capital letter)
  134. E<n> Character number n (probably in ASCII)
  135. E<html> Some non-numeric HTML entity, such
  136. as E<Agrave>
  137. =head2 The Intent
  138. That's it. The intent is simplicity, not power. I wanted paragraphs
  139. to look like paragraphs (block format), so that they stand out
  140. visually, and so that I could run them through fmt easily to reformat
  141. them (that's F7 in my version of B<vi>). I wanted the translator (and not
  142. me) to worry about whether " or ' is a left quote or a right quote
  143. within filled text, and I wanted it to leave the quotes alone, dammit, in
  144. verbatim mode, so I could slurp in a working program, shift it over 4
  145. spaces, and have it print out, er, verbatim. And presumably in a
  146. constant width font.
  147. In particular, you can leave things like this verbatim in your text:
  148. Perl
  149. FILEHANDLE
  150. $variable
  151. function()
  152. manpage(3r)
  153. Doubtless a few other commands or sequences will need to be added along
  154. the way, but I've gotten along surprisingly well with just these.
  155. Note that I'm not at all claiming this to be sufficient for producing a
  156. book. I'm just trying to make an idiot-proof common source for nroff,
  157. TeX, and other markup languages, as used for online documentation.
  158. Translators exist for B<pod2man> (that's for nroff(1) and troff(1)),
  159. B<pod2text>, B<pod2html>, B<pod2latex>, and B<pod2fm>.
  160. =head2 Embedding Pods in Perl Modules
  161. You can embed pod documentation in your Perl scripts. Start your
  162. documentation with a "=head1" command at the beginning, and end it
  163. with a "=cut" command. Perl will ignore the pod text. See any of the
  164. supplied library modules for examples. If you're going to put your
  165. pods at the end of the file, and you're using an __END__ or __DATA__
  166. cut mark, make sure to put an empty line there before the first pod
  167. directive.
  168. __END__
  169. =head1 NAME
  170. modern - I am a modern module
  171. If you had not had that empty line there, then the translators wouldn't
  172. have seen it.
  173. =head2 Common Pod Pitfalls
  174. =over 4
  175. =item *
  176. Pod translators usually will require paragraphs to be separated by
  177. completely empty lines. If you have an apparently empty line with
  178. some spaces on it, this can cause odd formatting.
  179. =item *
  180. Translators will mostly add wording around a LE<lt>E<gt> link, so that
  181. C<LE<lt>foo(1)E<gt>> becomes "the I<foo>(1) manpage", for example (see
  182. B<pod2man> for details). Thus, you shouldn't write things like C<the
  183. LE<lt>fooE<gt> manpage>, if you want the translated document to read
  184. sensibly.
  185. If you don need or want total control of the text used for a
  186. link in the output use the form LE<lt>show this text|fooE<gt>
  187. instead.
  188. =item *
  189. The script F<pod/checkpods.PL> in the Perl source distribution
  190. provides skeletal checking for lines that look empty but aren't
  191. B<only>, but is there as a placeholder until someone writes
  192. Pod::Checker. The best way to check your pod is to pass it through
  193. one or more translators and proofread the result, or print out the
  194. result and proofread that. Some of the problems found may be bugs in
  195. the translators, which you may or may not wish to work around.
  196. =back
  197. =head1 SEE ALSO
  198. L<pod2man> and L<perlsyn/"PODs: Embedded Documentation">
  199. =head1 AUTHOR
  200. Larry Wall