add list-table filter

_extensions/quarto-yaac/list-table.lua

@@ -0,0 +1,164 @@
+-- lua filter for RST-like list-tables in Markdown.
+-- Copyright (C) 2021 Martin Fischer, released under MIT license
+
+if PANDOC_VERSION and PANDOC_VERSION.must_be_at_least then
+    PANDOC_VERSION:must_be_at_least("2.11")
+else
+    error("pandoc version >=2.11 is required")
+end
+
+-- Get the list of cells in a row.
+local row_cells = function (row) return row.cells end
+
+-- "Polyfill" for older pandoc versions.
+if PANDOC_VERSION <= '2.16.2' then
+  -- previous pandoc versions used simple Attr/list pairs
+  pandoc.Row = function (cells) return {{}, cells} end
+  pandoc.TableHead = function (rows) return {{}, rows or {}} end
+  pandoc.TableFoot = function (rows) return {{}, rows or {}} end
+  pandoc.Cell = function (contents, align, rowspan, colspan, attr)
+    return {
+      attr = attr or pandoc.Attr(),
+      alignment = align or pandoc.AlignDefault,
+      contents = contents or {},
+      col_span = colspan or 1,
+      row_span = rowspan or 1
+    }
+  end
+  row_cells = function (row) return row[2] end
+end
+
+local alignments = {
+    d = 'AlignDefault',
+    l = 'AlignLeft',
+    r = 'AlignRight',
+    c = 'AlignCenter'
+}
+
+local function get_colspecs(div_attributes, column_count)
+    -- list of (align, width) pairs
+    local colspecs = {}
+
+    for i = 1, column_count do
+        table.insert(colspecs, {pandoc.AlignDefault, nil})
+    end
+
+    if div_attributes.aligns then
+        local i = 1
+        for a in div_attributes.aligns:gmatch('[^,]') do
+            assert(alignments[a] ~= nil,
+                   "unknown column alignment " .. tostring(a))
+            colspecs[i][1] = alignments[a]
+            i = i + 1
+        end
+        div_attributes.aligns = nil
+    end
+
+    if div_attributes.widths then
+        local total = 0
+        local widths = {}
+        for w in div_attributes.widths:gmatch('[^,]') do
+            table.insert(widths, tonumber(w))
+            total = total + tonumber(w)
+        end
+        for i = 1, column_count do
+            colspecs[i][2] = widths[i] / total
+        end
+        div_attributes.widths = nil
+    end
+
+    return colspecs
+end
+
+local function  new_table_body(rows, header_col_count)
+    return {
+        attr = {},
+        body = rows,
+        head = {},
+        row_head_columns = header_col_count
+    }
+end
+
+local function new_cell(contents)
+    local attr = {}
+    local colspan = 1
+    local rowspan = 1
+    local align = pandoc.AlignDefault
+
+    -- At the time of writing this Pandoc does not support attributes
+    -- on list items, so we use empty spans as a workaround.
+    if contents[1] and contents[1].content then
+        if contents[1].content[1] and contents[1].content[1].t == "Span" then
+            if #contents[1].content[1].content == 0 then
+                attr = contents[1].content[1].attr
+                table.remove(contents[1].content, 1)
+                colspan = attr.attributes.colspan or 1
+                attr.attributes.colspan = nil
+                rowspan = attr.attributes.rowspan or 1
+                attr.attributes.rowspan = nil
+                align = alignments[attr.attributes.align] or pandoc.AlignDefault
+                attr.attributes.align = nil
+            end
+        end
+    end
+
+    return pandoc.Cell(contents, align, rowspan, colspan, attr)
+end
+
+local function process(div)
+    if div.attr.classes[1] ~= "list-table" then return nil end
+    table.remove(div.attr.classes, 1)
+
+    local caption = {}
+
+    if div.content[1].t == "Para" then
+        local para = table.remove(div.content, 1)
+        caption = {pandoc.Plain(para.content)}
+    end
+
+    assert(div.content[1].t == "BulletList",
+           "expected bullet list, found " .. div.content[1].t)
+    local list = div.content[1]
+
+    local rows = {}
+
+    for i = 1, #list.content do
+        assert(#list.content[i] == 1, "expected item to contain only one block")
+        assert(list.content[i][1].t == "BulletList",
+               "expected bullet list, found " .. list.content[i][1].t)
+        local cells = {}
+        for _, cell_content in pairs(list.content[i][1].content) do
+            table.insert(cells, new_cell(cell_content))
+        end
+        local row = pandoc.Row(cells)
+        table.insert(rows, row)
+    end
+
+    local header_row_count = tonumber(div.attr.attributes['header-rows']) or 1
+    div.attr.attributes['header-rows'] = nil
+
+    local header_col_count = tonumber(div.attr.attributes['header-cols']) or 0
+    div.attr.attributes['header-cols'] = nil
+
+    local column_count = 0
+    for i = 1, #row_cells(rows[1] or {}) do
+        column_count = column_count + row_cells(rows[1])[i].col_span
+    end
+
+    local colspecs = get_colspecs(div.attr.attributes, column_count)
+    local thead_rows = {}
+    for i = 1, header_row_count do
+        table.insert(thead_rows, table.remove(rows, 1))
+    end
+
+    return pandoc.Table(
+        {long = caption, short = {}},
+        colspecs,
+        pandoc.TableHead(thead_rows),
+        {new_table_body(rows, header_col_count)},
+        pandoc.TableFoot(),
+        div.attr
+    )
+end
+
+return {{Div = process}}