lua filter to convert complex tables to list tables

Author: cscheid

crates/quarto-markdown-pandoc/tools/grid-table-fixer/grid-table-to-list-table.lua

@@ -0,0 +1,189 @@
+-- Lua filter to convert Pandoc grid tables to list-table format
+-- This produces output that can be processed by list-table.lua
+
+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
+
+-- Convert alignment enum to character code
+local function alignment_to_char(align)
+    local align_str = tostring(align)
+    if align_str == 'AlignLeft' then return 'l'
+    elseif align_str == 'AlignRight' then return 'r'
+    elseif align_str == 'AlignCenter' then return 'c'
+    else return 'd' end
+end
+
+-- Convert a cell to a list of blocks with optional attribute span prepended
+local function cell_to_blocks(cell)
+    -- Extract cell properties using Lua API
+    local contents = cell.contents
+    local align = cell.alignment
+    local rowspan = cell.row_span
+    local colspan = cell.col_span
+    local attr = cell.attr
+
+    -- Clone the blocks to avoid modifying the original
+    local blocks = pandoc.Blocks({})
+    for _, block in ipairs(contents) do
+        table.insert(blocks, block:clone())
+    end
+
+    -- If we have non-default cell attributes, prepend an empty span
+    local align_str = tostring(align)
+    if rowspan ~= 1 or colspan ~= 1 or align_str ~= 'AlignDefault' then
+        local span_attr = pandoc.Attr('', {}, {})
+        if colspan ~= 1 then
+            span_attr.attributes.colspan = tostring(colspan)
+        end
+        if rowspan ~= 1 then
+            span_attr.attributes.rowspan = tostring(rowspan)
+        end
+        if align_str ~= 'AlignDefault' then
+            span_attr.attributes.align = alignment_to_char(align)
+        end
+
+        local empty_span = pandoc.Span({}, span_attr)
+
+        -- Insert the empty span at the beginning of the first block's content
+        if #blocks > 0 and blocks[1].content then
+            table.insert(blocks[1].content, 1, empty_span)
+        else
+            -- If there's no content, create a paragraph with just the span
+            blocks = pandoc.Blocks({pandoc.Para({empty_span})})
+        end
+    end
+
+    -- Ensure we have at least one block
+    if #blocks == 0 then
+        blocks = pandoc.Blocks({pandoc.Para({})})
+    end
+
+    return blocks
+end
+
+-- Convert a Pandoc Table to a list-table Div
+local function table_to_list_table(tbl)
+    -- Extract table components using Lua API
+    local attr = tbl.attr
+    local caption = tbl.caption
+    local colspecs = tbl.colspecs
+    local thead = tbl.head
+    local tbodies = tbl.bodies
+    local tfoot = tbl.foot
+
+    -- Build div attributes, starting from table attributes
+    local div_attr = pandoc.Attr(attr.identifier, {'list-table'}, {})
+
+    -- Copy table classes
+    for _, class in ipairs(attr.classes) do
+        table.insert(div_attr.classes, class)
+    end
+
+    -- Copy table attributes
+    for k, v in pairs(attr.attributes) do
+        div_attr.attributes[k] = v
+    end
+
+    -- Count header rows from thead
+    local thead_rows = thead.rows
+    local header_row_count = #thead_rows
+    if header_row_count > 0 then
+        div_attr.attributes['header-rows'] = tostring(header_row_count)
+    end
+
+    -- Extract alignments and widths from colspecs
+    local aligns = {}
+    local widths = {}
+    local has_non_default_widths = false
+
+    for i, colspec in ipairs(colspecs) do
+        -- ColSpec is a pair: [1] = alignment, [2] = width
+        local align = colspec[1]
+        local width = colspec[2]
+
+        table.insert(aligns, alignment_to_char(align))
+
+        -- Width is a number (0.0-1.0) or ColWidthDefault
+        if type(width) == "number" and width > 0 then
+            table.insert(widths, tostring(width))
+            has_non_default_widths = true
+        else
+            -- ColWidthDefault or 0
+            table.insert(widths, "1")
+        end
+    end
+
+    -- Only add aligns if there are non-default alignments
+    local has_non_default_aligns = false
+    for _, a in ipairs(aligns) do
+        if a ~= 'd' then
+            has_non_default_aligns = true
+            break
+        end
+    end
+
+    if has_non_default_aligns then
+        div_attr.attributes.aligns = table.concat(aligns, ',')
+    end
+
+    if has_non_default_widths then
+        div_attr.attributes.widths = table.concat(widths, ',')
+    end
+
+    -- Build div content
+    local content = {}
+
+    -- Add caption if present
+    if caption and caption.long and #caption.long > 0 then
+        for _, block in ipairs(caption.long) do
+            table.insert(content, block)
+        end
+    end
+
+    -- Build list of rows (each row is a list item containing a bullet list of cells)
+    local row_items = {}
+
+    -- Add header rows
+    for _, row in ipairs(thead_rows) do
+        local cells = row.cells
+        local cell_blocks_list = {}
+        for _, cell in ipairs(cells) do
+            table.insert(cell_blocks_list, cell_to_blocks(cell))
+        end
+        -- Each row item contains a single bullet list of cells
+        table.insert(row_items, {pandoc.BulletList(cell_blocks_list)})
+    end
+
+    -- Add body rows from all table bodies
+    for _, tbody in ipairs(tbodies) do
+        for _, row in ipairs(tbody.body) do
+            local cells = row.cells
+            local cell_blocks_list = {}
+            for _, cell in ipairs(cells) do
+                table.insert(cell_blocks_list, cell_to_blocks(cell))
+            end
+            -- Each row item contains a single bullet list of cells
+            table.insert(row_items, {pandoc.BulletList(cell_blocks_list)})
+        end
+    end
+
+    -- Add footer rows if any
+    for _, row in ipairs(tfoot.rows) do
+        local cells = row.cells
+        local cell_blocks_list = {}
+        for _, cell in ipairs(cells) do
+            table.insert(cell_blocks_list, cell_to_blocks(cell))
+        end
+        table.insert(row_items, {pandoc.BulletList(cell_blocks_list)})
+    end
+
+    -- Create the outer bullet list (list of rows)
+    table.insert(content, pandoc.BulletList(row_items))
+
+    return pandoc.Div(content, div_attr)
+end
+
+return {{Table = table_to_list_table}}