Thanks for such a quick and helpful reply!

On Tuesday, December 19, 2017 at 4:28:08 PM UTC+8, Albert Krewinkel wrote:
>
> Mea culpa.  I broke MetaMaps when adding the List feature. Should be 
> fixed in master now. 
>
> As a quick fix, you can simply add a file `init.lua` to your pandoc data 
> directory (usually `~/.pandoc`) in which you re-add the function to the 
> pandoc module: 
>
>
>     pandoc = require 'pandoc' 
>     pandoc.mediabag = require 'pandoc.mediabag' 
>
>     pandoc.MetaMap = pandoc.MetaValue:create_constructor( 
>       "MetaMap", 
>       function (mm) return mm end 
>     ) 
>
> That should fix it. Sorry for the inconvenience. 
>
>
> John MacFarlane <j...-TVLZxgkOlNX2fBVCVOL8/A@public.gmane.org <javascript:>> writes: 
>
> > @tarleb, any idea what is happening here? 
> > 
> > +++ Greg Tucker-Kellogg [Dec 18 17 17:08 ]: 
> >>   This filter appears to fail  when the metadata includes elements such 
> >>   as multiple authors with keys. For example, the following fails when 
> >>   the metadata blocks is included (but not if the metadata block is a 
> >>   simple list of authors). 
> >>   The error message is 
> >>       Error running filter wordcount.lua: 
> >>       attempt to call a nil value 
> >>   And the return value is 83 
> >>   --- 
> >> 
> >> 
> >>   title: The document title 
> >> 
> >> 
> >>   author: 
> >> 
> >> 
> >>   - name: Author One 
> >> 
> >> 
> >>     affiliation: University of Somewhere 
> >> 
> >> 
> >>   - name: Author Two 
> >> 
> >> 
> >>     affiliation: University of Nowhere 
> >> 
> >> 
> >>   --- 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >>   # This document has a few words (14) 
> >> 
> >> 
> >> 
> >> 
> >> 
> >>   This is a test of some words 
> >> 
> >> 
> >>   On Tuesday, November 14, 2017 at 12:54:55 AM UTC+8, John MacFarlane 
> >>   wrote: 
> >> 
> >>     This lua filter can be used to count the words in a 
> >>     document, in any format pandoc can read.  It omits 
> >>     metadata words (title, abstract, authors), and of course 
> >>     it ignores all of the non-content words like HTML tags, 
> >>     LaTeX commands, the `#` that marks an ATX header, and 
> >>     so on. 
> >>     To use, save as wordcount.lua and do 
> >>         pandoc --lua-filter wordcount.lua inputfile 
> >>     ```lua 
> >>     -- counts words in a document 
> >>     words = 0 
> >>     wordcount = { 
> >>       Str = function(el) 
> >>         -- we don't count a word if it's entirely punctuation: 
> >>         if el.text:match("%P") then 
> >>             words = words + 1 
> >>         end 
> >>       end, 
> >>       Code = function(el) 
> >>         _,n = el.text:gsub("%S+","") 
> >>         words = words + n 
> >>       end, 
> >>       CodeBlock = function(el) 
> >>         _,n = el.text:gsub("%S+","") 
> >>         words = words + n 
> >>       end 
> >>     } 
> >>     function Pandoc(el) 
> >>         -- skip metadata, just count body: 
> >>         pandoc.walk_block(pandoc.Div(el.blocks), wordcount) 
> >>         print(words .. " words in body") 
> >>         os.exit(0) 
> >>     end 
> >>     ``` 
> >> 
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> >> 
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> >> 
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> >>   3. 
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>
> -- 
> Albert Krewinkel 
> GPG: 8eed e3e2 e8c5 6f18 81fe  e836 388d c0b2 1f63 1124 
>

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