Lua: update List module

The module now comes with a method `:at(index[, def])` that allows to access
indices, accepts negative indices to count from the end, and will return the
`def` value as a default if the list has no item at the given position.

Furthermore, the list constructor `pandoc.List` now accepts iterators. E.g.,
`pandoc.List(text:gmatch '%S+')` returns the list of words in `text`.

Closes: #9835

1 files changed, 25 insertions, 0 deletions

diff --git a/doc/lua-filters.md b/doc/lua-filters.md
index 9de10cfbf..f445f6327 100644
--- a/doc/lua-filters.md
+++ b/doc/lua-filters.md
@@ -4578,6 +4578,28 @@ Returns:
 
 ## Methods
 
+### `pandoc.List:at` {#pandoc.list:at}
+
+`:at (index[, default])`
+
+Returns the element at the given index, or `default` if the list
+contains no item at the given position.
+
+Negative integers count back from the last item in the list.
+
+Parameters:
+
+`index`
+:   element position (integer)
+
+`default`
+:   the default value that is returned if the index is out of
+    range (any)
+
+Returns:
+
+-   the list item at `index`, or `default`.
+
 ### `pandoc.List:clone ()` {#pandoc.list:clone}
 
 Returns a (shallow) copy of the list. (To get a deep copy
@@ -4683,6 +4705,9 @@ Parameters:
 Create a new List. If the optional argument `table` is given,
 set the metatable of that value to `pandoc.List`.
 
+The function also accepts an iterator, in which case it creates a
+new list from the return values of the iterator function.
+
 Parameters:
 
 `table`