I am noticing the list items have some very context-sensitive specific behavior regarding ownership of the trailing blank lines. I was hoping to get some clarification on this (namely, are my observations correct, am I stumbling across a bug, or have I not dug deep enough to suss out the real rules?). The org-mode documentation states:
> With the exception of list items and footnote definitions blank lines belong > to the preceding element with the narrowest possible scope but it does not state who ends up owning those blank lines. In a previous email the incredibly helpful Ihor Radchenko expanded on this further with: > Also, in addition to list items, footnote-definitions do not extend their > contents to the trailing blank lines. which, I would interpret as the list items do not own their trailing blank lines but rather the list owns them. But that is not the behavior I am seeing. If I had to summarize the behavior I am seeing into words it would be: > List items own their trailing blank lines unless they are both the final list > item and not the final element of a non-final list item. Below I have how I reached this conclusion, but before diving into the weeds I want to point two things out: 1. I have hastily thrown together a tool to help rapidly visualize the ownership of nodes in org-mode's AST. Before this tool, I was manually running org-element-parse-buffer and using M-g c to jump around to the various indices to see where nodes started/ended. With this tool, I can paste in my org-mode source and get a tree showing the contents of each node and I can click on the nodes to highlight the relevant characters in the org-mode source. It is available at https://github.com/tomalexander/org_mode_ast_investigation_tool . 2. I have flattened my analysis for plain-text consumption over email below, but if you'd prefer the original org-mode version of this investigation it is available at https://github.com/tomalexander/org_mode_ast_investigation_tool/blob/cba1d1e988be230f3104f5f63dfaeaaf5cd0d280/notes/plain_list_ownership_notes.org . And now, here is how I reached that conclusion: *** Test case 1 ``` 1. foo 1. bar 2. baz 2. lorem ipsum ``` | Plain List *Item* | Owns trailing blank lines | |------------------------+---------------------------| | foo (includes bar baz) | Yes | | bar | Yes | | baz | Yes | | lorem | No | In this test case, we see that the only list item that doesn't own its trailing blank lines is "lorem", the final list item of the outer-most list. *** Test case 2 We add "cat" as a paragraph at the end of foo which makes "baz" lose its trailing blank lines ``` 1. foo 1. bar 2. baz cat 2. lorem ipsum ``` | Plain List *Item* | Owns trailing blank lines | |-------------------------------+---------------------------| | foo -> cat (includes bar baz) | Yes | | bar | Yes | | baz | No | | lorem | No | In isolation, this implies that the final plain list item does not own its trailing blank lines, which conflicts with "baz" from test 1. New theory: List items own their trailing blank lines unless they are both the final list item and not the final element of a list item. Adding why to the table: | Plain List *Item* | Owns trailing blank lines | Why | |-------------------------------+---------------------------+-----------------------------------------------------------| | foo -> cat (includes bar baz) | Yes | Not the final list item | | bar | Yes | Not the final list item | | baz | No | Final item of bar->baz and not the final element of "foo" | | lorem | No | Final item of foo->lorem and not contained in a list item | *** Test case 3 So if that theory is true, taking the entire (foo -> lorem) list from test 1 and nesting it inside a list should coerce "lorem" to own its trailing blank lines since it would then be a final list item (of foo -> lorem) and the final element of the new list. ``` 1. cat 1. foo 1. bar 2. baz 2. lorem ipsum ``` | Plain List *Item* | Owns trailing blank lines | |-----------------------------+---------------------------| | cat (includes foo -> lorem) | No | | foo (includes bar baz) | Yes | | bar | Yes | | baz | Yes | | lorem | No | Against expectations, we did not coerce lorem to consume its trailing blank lines. What is different between "baz" and "lorem"? Well, "baz" is contained within "foo" which has a "lorem" after it, whereas "lorem" is contained within "cat" which does not have any list items after it. New theory: List items own their trailing blank lines unless they are both the final list item and not the final element of a non-final list item. | Plain List *Item* | Owns trailing blank lines | Why | |-----------------------------+---------------------------+------------------------------------------------------| | cat (includes foo -> lorem) | No | Final list item and not contained in a list item | | foo (includes bar baz) | Yes | Not the final list item | | bar | Yes | Not the final list item | | baz | Yes | Final element of non-final list item | | lorem | No | Final list item and final element of final list item | *** Test case 4 So if that theory is true, then we should be able to coerce lorem to consume its trailing blank lines by adding a second item to the cat list. ``` 1. cat 1. foo 1. bar 2. baz 2. lorem 2. dog ipsum ``` | Plain List *Item* | Owns trailing blank lines | |-----------------------------+---------------------------| | cat (includes foo -> lorem) | Yes | | foo (includes bar baz) | Yes | | bar | Yes | | baz | Yes | | lorem | Yes | | dog | No | For the first time our expectations were met! Enduring theory: List items own their trailing blank lines unless they are both the final list item and not the final element of a non-final list item. | Plain List *Item* | Owns trailing blank lines | Why | |-----------------------------+---------------------------+--------------------------------------------------| | cat (includes foo -> lorem) | Yes | Not the final list item | | foo (includes bar baz) | Yes | Not the final list item | | bar | Yes | Not the final list item | | baz | Yes | Final element of non-final list item | | lorem | Yes | Final element of non-final list item | | dog | No | Final list item and not contained in a list item | -- Tom Alexander
