diff --git a/doc/forum/Questions_about_a_new_plugin.mdwn b/doc/forum/Questions_about_a_new_plugin.mdwn new file mode 100644 index 000000000..970c103de --- /dev/null +++ b/doc/forum/Questions_about_a_new_plugin.mdwn @@ -0,0 +1,41 @@ +Hello, +I have a plugin in mind, but before starting to write some code, I come to you to see if something similar already exists, or if there is an easier way to do it. + +# What I want + +I want to be able to have several versions of the same page. For instance (this is not my usecase, but it matches exactly), let's say I am developping a software, with several versions published, and I want: + +* the latest documentation to be available at ``http://example.com/doc``; +* the documentation for previous (or current version, with permanent URL) available at ``http://example.com/doc/v2_0``. + +What I am thinking about is: + +* my wiki has the documentation written in pages `doc/v1_0.mdwn`, `doc/v2_0.mdwn`, and so on; +* the `doc.mdwn` page contains nothing but code to copy metadata from the latest `doc/*mdwn` page, that is: [[plugins/meta]] information, [[plugins/tag]], and [[plugins/contrib/ymlfront]]. + +# What I have in mind + +What I have in mind is a plugin providing a directive ``pageversion`` such that the `doc.mdwn` page contains only: + + [[!pageversion pages="doc/* and !doc/*/*"]] + +This would grab the latest documentation page, copy its content, and copy meta information, tags and fields. + +# How to do it + +I see two ways to do it, but both have big drawbacks. + +* I could, in the ``preprocess`` function of the plugin, copy the *interesting* part of the ``%pagestate`` global variable. In pseudo-code, something like: + + $pagestate{doc}{meta} = $pagestate{doc/v2_0}{meta}; + $pagestate{doc}{fields} = $pagestate{doc/v2_0}{fields}; + $pagestate{doc}{tags} = $pagestate{doc/v2_0}{tags}; # This one definitely would not work, but it is pseudo-code + + I fear that some necessary side effects would not occur. For instance, setting date using the [[plugins/meta]] plugin [sets the page creation time at a deeper level](http://source.ikiwiki.branchable.com/?p=source.git;a=blob;f=IkiWiki/Plugin/meta.pm;h=ea099f955ac1c486cdd2baf6636e330a8eae569c;hb=HEAD#l154). Copying ``%pagestate`` would bypass this. + +* I could, in the ``preprocess`` function, call the ``preprocess`` function for those three plugins. But this would mean guessing what the original directive arguments were, which can be tricky. + +# My questions + +* Does something similar already exist? +* Do you have any better idea about how to do it?