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slightly refactor the table filter
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@chrisfenner
chrisfenner committed Feb 8, 2024
1 parent f8fd0ce commit 5a0e11e
Showing 1 changed file with 131 additions and 126 deletions.
257 changes: 131 additions & 126 deletions filter/tabularx.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -51,150 +51,155 @@ function GetCellCode(cell)
return cell_code
end

-- This function iterates a List of Rows and creates the code for each row.
-- The 'width' parameter is a necessary hint due to potential column-spanning.
-- If 'header' is true, we style every element in bold.
-- If 'no_first_hline' is true, we omit the first hline (if applicable).
-- If 'plain' is true, we don't change the colors (but keep it bold).
-- https://pandoc.org/lua-filters.html#type-list
-- https://pandoc.org/lua-filters.html#type-row
-- TODO: This code's a real spaghetti factory. Refactor it in the future.
function TabularRows(rows, header, no_first_hline, plain, colspecs)
function TabularRow(height, colspecs, skips, rows_with_rowspans, row, i, plain, no_first_hline, header)
local width = Length(colspecs)
local height = Length(rows)
local latex_code = ''
-- Keep a 2d array of bools for which cells we know we need to skip.
local skips = {}
local rows_with_rowspans = {}

-- For each row in the list of rows,
for i, row in ipairs(rows) do
local n = 1
-- Prepare a list of latex snippets to be concatenated together below.
local row_code = {}

-- Draw horizontal rules using cline, for each non-skipped cell (so we don't draw a line through a rowspan cell).
local clines_code = ''
local any_skips = false
if not plain and (i > 1 or not no_first_hline) then
for j = 1,width do
if skips[(i-1)*width + j] then
any_skips = true
else
clines_code = clines_code .. string.format("\\cline{%d-%d}", j, j)
end
end
-- Simplify a whole row of clines as just an hline.
-- In addition to making the LaTeX code prettier, this serves an
-- important purpose. clines can be separated from their row
-- (in the case of a page break) while hlines are kept with with
-- their row.
-- Since xltabular avoids breaking rowspans across pages,
-- we completely avoid problems like
-- https://github.com/TrustedComputingGroup/pandoc/issues/115
-- by doing this.
if not any_skips then
clines_code = "\\hline"
local n = 1
-- Prepare a list of latex snippets to be concatenated together below.
local row_code = {}

-- Draw horizontal rules using cline, for each non-skipped cell (so we don't draw a line through a rowspan cell).
local clines_code = ''
local any_skips = false
if not plain and (i > 1 or not no_first_hline) then
for j = 1,width do
if skips[(i-1)*width + j] then
any_skips = true
else
clines_code = clines_code .. string.format("\\cline{%d-%d}", j, j)
end
end
-- Simplify a whole row of clines as just an hline.
-- In addition to making the LaTeX code prettier, this serves an
-- important purpose. clines can be separated from their row
-- (in the case of a page break) while hlines are kept with with
-- their row.
-- Since xltabular avoids breaking rowspans across pages,
-- we completely avoid problems like
-- https://github.com/TrustedComputingGroup/pandoc/issues/115
-- by doing this.
if not any_skips then
clines_code = "\\hline"
end
end

-- For each cell in the row,
local j = 1
while j <= width do
-- We may need to leave this cell empty due to a previous row/colspan.
if skips[(i-1)*width + j] then
-- Even more complicated: We may need to put a multicolumn here (in the event that there are multiple
-- skipped cells in a row).
local skipstart = j
local skipend = j
while skips[(i-1)*width + skipend+1] do
skipend = skipend + 1
end
if skipstart == skipend then
table.insert(row_code, ' ')
else
local left_line = ''
local right_line = ''
if not plain then
if skipstart == 1 then
-- We only have to put a | on the left side of the colspec if we're the leftmost column.
left_line = '|'
end
right_line = '|'
-- For each cell in the row,
local j = 1
while j <= width do
-- We may need to leave this cell empty due to a previous row/colspan.
if skips[(i-1)*width + j] then
-- Even more complicated: We may need to put a multicolumn here (in the event that there are multiple
-- skipped cells in a row).
local skipstart = j
local skipend = j
while skips[(i-1)*width + skipend+1] do
skipend = skipend + 1
end
if skipstart == skipend then
table.insert(row_code, ' ')
else
local left_line = ''
local right_line = ''
if not plain then
if skipstart == 1 then
-- We only have to put a | on the left side of the colspec if we're the leftmost column.
left_line = '|'
end
table.insert(row_code, string.format('\\multicolumn{%d}{%sl%s}{ }', (skipend-skipstart) + 1, left_line, right_line))
end
j = j + (skipend-skipstart) + 1
-- Otherwise, let's write some content into the cell.
elseif row.cells[n] then
local cell = row.cells[n]
local cell_code = '{' .. GetCellCode(cell) .. '}'
if header then
cell_code = '{\\bfseries ' .. cell_code .. '}'
right_line = '|'
end
table.insert(row_code, string.format('\\multicolumn{%d}{%sl%s}{ }', (skipend-skipstart) + 1, left_line, right_line))
end
j = j + (skipend-skipstart) + 1
-- Otherwise, let's write some content into the cell.
elseif row.cells[n] then
local cell = row.cells[n]
local cell_code = '{' .. GetCellCode(cell) .. '}'
if header then
cell_code = '{\\bfseries ' .. cell_code .. '}'
end

-- If this sell spans columns, we have to use multicolumn.
-- If this cell spans rows, we have to use multirow.
-- We also need to tell ourselves about it, because we have to write blanks for all
-- the cells that get covered up empty.
if cell.row_span > 1 or cell.col_span > 1 then
if cell.row_span > 1 then
for skipi=i,i+cell.row_span-1 do
rows_with_rowspans[skipi] = true
end
cell_code = string.format('\\multirow{%d}{=}{%s}', cell.row_span, cell_code)
-- If this sell spans columns, we have to use multicolumn.
-- If this cell spans rows, we have to use multirow.
-- We also need to tell ourselves about it, because we have to write blanks for all
-- the cells that get covered up empty.
if cell.row_span > 1 or cell.col_span > 1 then
if cell.row_span > 1 then
for skipi=i,i+cell.row_span-1 do
rows_with_rowspans[skipi] = true
end
local left_line = ''
local right_line = ''
if not plain then
if j == 1 then
-- We only have to put a | on the left side of the colspec if we're the leftmost column.
left_line = '|'
end
right_line = '|'
cell_code = string.format('\\multirow{%d}{=}{%s}', cell.row_span, cell_code)
end
local left_line = ''
local right_line = ''
if not plain then
if j == 1 then
-- We only have to put a | on the left side of the colspec if we're the leftmost column.
left_line = '|'
end
if cell.col_span > 1 then
-- Get the total width of all the columns we're spanning.
-- This allows us to place block elements inside multicolumn cells.
local total_column_width = ColumnWidth(colspecs[j])
for z = j+1,j+cell.col_span-1 do
total_column_width = total_column_width .. '+' .. ColumnWidth(colspecs[z])
end
total_column_width = total_column_width .. ColumnAdjustmentValue
cell_code = string.format('\\multicolumn{%d}{%sp{%s}%s}{%s}', cell.col_span, left_line, total_column_width, right_line, cell_code)
right_line = '|'
end
if cell.col_span > 1 then
-- Get the total width of all the columns we're spanning.
-- This allows us to place block elements inside multicolumn cells.
local total_column_width = ColumnWidth(colspecs[j])
for z = j+1,j+cell.col_span-1 do
total_column_width = total_column_width .. '+' .. ColumnWidth(colspecs[z])
end

-- Mark skips for the next rows but not the current one.
-- tabularx/multirow/multicolumn want us to NOT provide empty "& &" cells after a multicolumn.
-- Multirow cells DO need empty "& &" cells populated.
for skipi=i+1,i+cell.row_span-1 do
for skipj=j,j+cell.col_span-1 do
skips[(skipi-1)*width + skipj] = true
end
total_column_width = total_column_width .. ColumnAdjustmentValue
cell_code = string.format('\\multicolumn{%d}{%sp{%s}%s}{%s}', cell.col_span, left_line, total_column_width, right_line, cell_code)
end

-- Mark skips for the next rows but not the current one.
-- tabularx/multirow/multicolumn want us to NOT provide empty "& &" cells after a multicolumn.
-- Multirow cells DO need empty "& &" cells populated.
for skipi=i+1,i+cell.row_span-1 do
for skipj=j,j+cell.col_span-1 do
skips[(skipi-1)*width + skipj] = true
end
end

-- Store this cell's code for concatenation below.
table.insert(row_code, cell_code)
-- Increment j by the colspan of the current cell.
j = j + cell.col_span
n = n + 1
else
-- Not skipping this cell, but we have no more data. That means we're done with this row.
break
end
end

local linebreak = '\\\\'
if header or i == height or rows_with_rowspans[i] then
-- Use the \\* break which keeps rows together even when there's a page break.
-- Use this on header/footer lines, the last row in the body, and on
-- any rows where there was a rowspan.
linebreak = linebreak .. '*'
-- Store this cell's code for concatenation below.
table.insert(row_code, cell_code)
-- Increment j by the colspan of the current cell.
j = j + cell.col_span
n = n + 1
else
-- Not skipping this cell, but we have no more data. That means we're done with this row.
break
end
end

local linebreak = '\\\\'
if header or i == height or rows_with_rowspans[i] then
-- Use the \\* break which keeps rows together even when there's a page break.
-- Use this on header/footer lines, the last row in the body, and on
-- any rows where there was a rowspan.
linebreak = linebreak .. '*'
end

return clines_code .. ' ' .. table.concat(row_code, ' & ') .. string.format(' %s\n', linebreak)
end

-- This function iterates a List of Rows and creates the code for each row.
-- If 'header' is true, we style every element in bold.
-- If 'no_first_hline' is true, we omit the first hline (if applicable).
-- If 'plain' is true, we don't change the colors (but keep it bold).
-- https://pandoc.org/lua-filters.html#type-list
-- https://pandoc.org/lua-filters.html#type-row
function TabularRows(rows, header, no_first_hline, plain, colspecs)
local height = Length(rows)
local latex_code = ''
-- Keep a 2d array of bools for which cells we know we need to skip.
local skips = {}
local rows_with_rowspans = {}

-- For each row in the list of rows,
for i, row in ipairs(rows) do
local row_code = TabularRow(height, colspecs, skips, rows_with_rowspans, row, i, plain, no_first_hline, header)

-- The entire row is all the cells joined by '&' with a '\\' at the end.
latex_code = latex_code .. clines_code .. ' ' .. table.concat(row_code, ' & ') .. string.format(' %s\n', linebreak)
latex_code = latex_code .. row_code .. '\n'
end

latex_code = latex_code .. '\n'
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