Lua: allow table structure as format spec.

This allows to pass structured values as format specifiers to
`pandoc.write` and `pandoc.read`.

2 files changed, 21 insertions, 9 deletions

diff --git a/doc/custom-readers.md b/doc/custom-readers.md
index 2d9938121..e0b6e4915 100644
--- a/doc/custom-readers.md
+++ b/doc/custom-readers.md
@@ -98,10 +98,10 @@ end
 Custom readers can be built such that their behavior is
 controllable through format extensions, such as `smart`,
 `citations`, or `hard-line-breaks`. Supported extensions are those
-that are present as a key in the global `Extensions` table.
-Fields of extensions that are enabled default have the value
-`true`, while those that are supported but disabled have value
-`false`.
+that are present as a key in the global `Extensions` table. Fields
+of extensions that are enabled default have the value `true` or
+`enable`, while those that are supported but disabled have value
+`false` or `disable`.
 
 Example: A writer with the following global table supports the
 extensions `smart`, `citations`, and `foobar`, with `smart` enabled and
@@ -109,9 +109,9 @@ the other two disabled by default:
 
 ``` lua
 Extensions = {
-  smart = true,
-  citations = false,
-  foobar = false
+  smart = 'enable',
+  citations = 'disable',
+  foobar = true
 }
 ```
 
diff --git a/doc/lua-filters.md b/doc/lua-filters.md
index 5cefa28de..762c893f8 100644
--- a/doc/lua-filters.md
+++ b/doc/lua-filters.md
@@ -3495,13 +3495,23 @@ reStructuredText, and Org, then these will be included in the
 resulting document. Any media elements are added to those
 retrieved from the other parsed input files.
 
+The `format` parameter defines the format flavor that will be
+parsed. This can be either a string, using `+` and `-` to enable
+and disable extensions, or a table with fields `format` (string)
+and `extensions` (table). The `extensions` table can be a list of
+all enabled extensions, or a table with extensions as keys and
+their activation status as values (`true` or `'enable'` to enable
+an extension, `false` or `'disable'` to disable it).
+
 Parameters:
 
 `markup`
 :   the markup to be parsed (string|Sources)
 
 `format`
-:   format specification, defaults to `"markdown"` (string)
+:   format specification; defaults to `"markdown"`. See the
+    description above for a complete description of this
+    parameter. (string|table)
 
 `reader_options`
 :   options passed to the reader; may be a ReaderOptions object or
@@ -3532,7 +3542,9 @@ Parameters:
 :   document to convert ([Pandoc](#type-pandoc))
 
 `format`
-:   format specification, defaults to `'html'` (string)
+:   format specification; defaults to `"html"`. See the
+    documentation of [`pandoc.read`](#pandoc.read) for a complete
+    description of this parameter. (string|table)
 
 `writer_options`
 :   options passed to the writer; may be a WriterOptions object