cortav  Diff

				table.insert(ret, (hookfn(me:delegate(ext),...)))
			end
			return ret
		end;
	};
}

-- renderer engines
function ct.render.html(doc, opts)
	local doctitle = opts['title']








	local f = string.format































































	local ids = {}
	local canonicalID = {}
	local function getSafeID(obj,pfx)

		pfx = pfx or ''
		if canonicalID[obj] then
			return canonicalID[obj]
		elseif obj.id and ids[pfx .. obj.id] then
			local objid = pfx .. obj.id
			local newid
			local i = 1
................................................................................
					i = i + 1 until not ids[cid]
			end
			ids[cid] = obj
			canonicalID[obj] = cid
			return cid
		end
	end

	local footnotes = {}
	local footnotecount = 0

	local langsused = {}
	local langpairs = {
		lua = { color = 0x9377ff };
		terra = { color = 0xff77c8 };
		c = { name = 'C', color = 0x77ffe8 };
		html = { color = 0xfff877 };
		scheme = { color = 0x77ff88 };
		lisp = { color = 0x77ff88 };
		fortran = { color = 0xff779a };
		python = { color = 0xffd277 };
		ruby = { color = 0xcdd6ff };
	}

	local stylesets = {
		footnote = [[
			div.footnote {
			font-family: 90%;
				display: none;
				grid-template-columns: 1em 1fr min-content;
				grid-template-rows: 1fr min-content;
				position: fixed;
				padding: 1em;
				background: @tone(0.05);
				border: black;
				margin:auto;
			}
			div.footnote:target { display:grid; }
			@media screen {
				div.footnote {
					left: 10em;
					right: 10em;
					max-width: calc(@width + 2em);
					max-height: 30vw;
					bottom: 1em;
				}
			}
			@media print {
				div.footnote {
					position: relative;
				}
				div.footnote:first-of-type {
					border-top: 1px solid black;
				}
			}

			div.footnote > a[href="#0"]{
				grid-row: 2/3;
				grid-column: 3/4;
				display: block;
				padding: 0.2em 0.7em;
				text-align: center;
				text-decoration: none;
				background: @tone(0.2);
				color: @tone(1);
				border: 1px solid black;
				margin-top: 0.6em;
				-webkit-user-select: none;
				-ms-user-select: none;
				user-select: none;
				-webkit-user-drag: none;
				user-drag: none;
			}
			div.footnote > a[href="#0"]:hover {
				background: @tone(0.3);
				color: @tone(2);
			}
			div.footnote > a[href="#0"]:active {
				background: @tone(0.05);
				color: @tone(0.4);
			}
			@media print {
				div.footnote > a[href="#0"]{
					display:none;
				}
			}
			div.footnote > div.number {
				text-align:right;
				grid-row: 1/2;
				grid-column: 1/2;
			}
			div.footnote > div.text {
				grid-row: 1/2;
				grid-column: 2/4;
				padding-left: 1em;
				overflow-y: scroll;
			}
		]];
		header = [[
			body { padding: 0 2.5em !important }
			h1,h2,h3,h4,h5,h6 { border-bottom: 1px solid @tone(0.7); }
			h1 { font-size: 200%; border-bottom-style: double !important; border-bottom-width: 3px !important; margin: 0em -1em; }
			h2 { font-size: 130%; margin: 0em -0.7em; }
			h3 { font-size: 110%; margin: 0em -0.5em; }
			h4 { font-size: 100%; font-weight: normal; margin: 0em -0.2em; }
			h5 { font-size: 90%; font-weight: normal; }
			h6 { font-size: 80%; font-weight: normal; }
			h3, h4, h5, h6 { border-bottom-style: dotted !important; }
			h1,h2,h3,h4,h5,h6 { 
				margin-top: 0;
				margin-bottom: 0;
			}
			:is(h1,h2,h3,h4,h5,h6) + p {
				margin-top: 0.4em;
			}

		]];
		headingAnchors = [[
			:is(h1,h2,h3,h4,h5,h6) > a[href].anchor {
				text-decoration: none;
				font-size: 1.2em;
				padding: 0.3em;
				opacity: 0%;
				transition: 0.3s;
				font-weight: 100;
			}
			:is(h1,h2,h3,h4,h5,h6):hover > a[href].anchor {
				opacity: 50%;
			}
			:is(h1,h2,h3,h4,h5,h6) > a[href].anchor:hover {
				opacity: 100%;
			}

			]] .. -- this is necessary to avoid the sections jumping around
			      -- when focus changes from one to another
			[[ section {
				border: 1px solid transparent;
			}

			section:target {
				margin-left: -2em;
				margin-right: -2em;
				padding: 0 2em;
				background: @tone(0.04);
				border: 1px dotted @tone(0.3);
			}

			section:target > :is(h1,h2,h3,h4,h5,h6) {

			}
		]];
		paragraph = [[
			p {
				margin: 0.7em 0;
				text-align: justify;
			}
			section {
				margin: 1.2em 0;
			}
			section:first-child { margin-top: 0; }
		]];
		accent = [[
			@media screen {
				body { background: @bg; color: @fg }
				a[href] {
					color: @tone(0.7 30);
					text-decoration-color: @tone/0.4(0.7 30);
				}
				a[href]:hover {
					color: @tone(0.9 30);
					text-decoration-color: @tone/0.7(0.7 30);
				}
				h1 { color: @tone(2); }
				h2 { color: @tone(1.5); }
				h3 { color: @tone(1.2); }
				h4 { color: @tone(1); }
				h5,h6 { color: @tone(0.8); }
			}
			@media print {
				a[href] {
					text-decoration: none;
					color: black;
					font-weight: bold;
				}
				h1,h2,h3,h4,h5,h6 {
					border-bottom: 1px black;
				}
			}
		]];
		aside = [[
			section > aside {
				text-align: justify;
				margin: 0 1.5em;
				padding: 0.5em 0.8em;
				background: @tone(0.05);
				font-size: 90%;
				border-left: 5px solid @tone(0.2 15);
				border-right: 5px solid @tone(0.2 15);
			}
			section > aside p {
				margin: 0;
				margin-top: 0.6em;
			}
			section > aside p:first-child {
				margin: 0;
			}
      ]];
		code = [[
			code {
				display: inline-block;
				background: @tone(0.9);
				color: @bg;
				font-family: monospace;
				font-size: 90%;
				padding: 3px 5px;
			}
		]];
		var = [[
			var {
				font-style: italic;
				font-family: monospace;
				color: @tone(0.7);
			}
			code var {
				color: @tone(0.25);
			}
		]];
		math = [[
			span.equation {
				display: inline-block;
				background: @tone(0.08);
				color: @tone(2);
				padding: 0.1em 0.3em;
				border: 1px solid @tone(0.5);
			}
		]];
		abbr = [[
			abbr[title] { cursor: help; }
		]];
		editors_markup = [[]];
		block_code_listing = [[
			figure.listing {
				font-family: monospace;
				background: @tone(0.05);
				color: @fg;
				padding: 0;
				margin: 0.3em 0;
				counter-reset: line-number;
				position: relative;
				border: 1px solid @fg;
			}
			figure.listing>div {
				white-space: pre-wrap;
				tab-size: 3;
				-moz-tab-size: 3;
				counter-increment: line-number;
				text-indent: -2.3em;
				margin-left: 2.3em;
			}
			figure.listing>:is(div,hr)::before {
				width: 1.0em;
				padding: 0.2em 0.4em;
				text-align: right;
				display: inline-block;
				background-color: @tone(0.2);
				border-right: 1px solid @fg;
				content: counter(line-number);
				margin-right: 0.3em;
			}
			figure.listing>hr::before {
				color: transparent;
				padding-top: 0;
				padding-bottom: 0;
			}
			figure.listing>div::before {
				color: @fg;
			}
			figure.listing>div:last-child::before {
				padding-bottom: 0.5em;
			}
			figure.listing>figcaption:first-child {
				border: none;
				border-bottom: 1px solid @fg;
			}
			figure.listing>figcaption::after {
				display: block;
				float: right;
				font-weight: normal;
				font-style: italic;
				font-size: 70%;
				padding-top: 0.3em;
			}
			figure.listing>figcaption {
				font-family: sans-serif;
				font-size: 120%;
				padding: 0.2em 0.4em;
				border: none;
				color: @tone(2);
			}
			figure.listing > hr {
				border: none;
				margin: 0;
				height: 0.7em;
				counter-increment: line-number;
			}
		]];
	}

	local stylesNeeded = {}

	local render_state_handle = {
		doc = doc;
		opts = opts;
		style_rules = styles; -- use stylesneeded if at all possible
		stylesets = stylesets;
		stylesets_active = stylesNeeded;
		obj_htmlid = getSafeID;
		-- remaining fields added later
	}

	local renderJob = doc:job('render_html', nil, render_state_handle)
	doc.stage.job = renderJob;

	local runhook = function(h, ...)
		return renderJob:hook(h, render_state_handle, ...)
	end

	local tagproc do
		local elt = function(t,attrs)
			return f('<%s%s>', t,
				attrs and ss.reduce(function(a,b) return a..b end, '',
					ss.map(function(v,k)
						if v == true
							then          return ' '..k
							elseif v then return f(' %s="%s"', k, v)
						end
					end, attrs)) or '')
		end

		tagproc = {
			toTXT = {
				tag = function(t,a,v) return v  end;
				elt = function(t,a)   return '' end;
				catenate = table.concat;
			};
			toIR = {
				tag = function(t,a,v,o) return {
					tag = t, attrs = a;
					nodes = type(v) == 'string' and {v} or v, src = o
				} end;

				elt = function(t,a,o) return {
					tag = t, attrs = a, src = o
				} end;

				catenate = function(...) return ... end;
			};
			toHTML = {
				elt = elt;
				tag = function(t,attrs,body)
					return f('%s%s</%s>', elt(t,attrs), body, t)
				end;
				catenate = table.concat;
			};
		}
	end

	local function getBaseRenderers(procs, span_renderers)
		local tag, elt, catenate = procs.tag, procs.elt, procs.catenate
		local htmlDoc = function(title, head, body)
			return [[<!doctype html>]] .. tag('html',nil,
				tag('head', nil,
					elt('meta',{charset = 'utf-8'}) ..
					(title and tag('title', nil, title) or '') ..
					(head or '')) ..
				tag('body', nil, body or ''))
		end

		local function htmlSpan(spans, block, sec)
			local text = {}
			for k,v in pairs(spans) do
				if type(v) == 'string' then
					v=v:gsub('[<>&"]', function(x)
							return string.format('&#%02u;', string.byte(x))
						end)
					for fn, ext in renderJob:each('hook','render_html_sanitize') do
						v = fn(renderJob:delegate(ext), v)
					end
					table.insert(text,v)
				else
					table.insert(text, (span_renderers[v.kind](v, block, sec)))
				end
			end
			return table.concat(text)
		end
		return {htmlDoc=htmlDoc, htmlSpan=htmlSpan}
	end

	local spanparse = function(...)
		local s = ct.parse_span(...)
		doc.docjob:hook('meddle_span', s)
		return s
	end

	local cssRulesFor = {}
	local function getSpanRenderers(procs)
		local tag, elt, catenate = procs.tag, procs.elt, procs.catenate
		local span_renderers = {}
		local plainrdr = getBaseRenderers(tagproc.toTXT, span_renderers)
		local htmlSpan = getBaseRenderers(procs, span_renderers).htmlSpan

		function span_renderers.format(sp,...)
			local tags = { strong = 'strong', emph = 'em', strike = 'del', insert = 'ins', literal = 'code', variable = 'var'}
			if sp.style == 'literal' and not opts['fossil-uv'] then
				stylesNeeded.code = true
			elseif sp.style == 'strike' or sp.style == 'insert' then
				stylesNeeded.editors_markup = true
			elseif sp.style == 'variable' then
				stylesNeeded.var = true
			end
			return tag(tags[sp.style],nil,htmlSpan(sp.spans,...))
		end

		function span_renderers.deref(t,b,s)
			local r = b.origin:ref(t.ref)
			local name = t.ref
			if name:find'%.' then name = name:match '^[^.]*%.(.+)$' end
			if type(r) == 'string' then
				stylesNeeded.abbr = true
				return tag('abbr',{title=r},next(t.spans) and htmlSpan(t.spans,b,s) or name)
			end
			if r.kind == 'resource' then
				local rid = getSafeID(r, 'res-')
				if r.class == 'image' then
					if not cssRulesFor[r] then
						local css = prepcss(string.format([[
							section p > .%s {
							}
						]], rid))
						stylesets[r] = css
						cssRulesFor[r] = css
						stylesNeeded[r] = true
					end
					return tag('div',{class=rid},catenate{'blaah'})
				elseif r.class == 'video' then
					local vid = {}
					return tag('video',nil,vid)
				elseif r.class == 'font' then
					b.origin:fail('fonts cannot be instantiated, use %font directive instead')
				end
			else
				b.origin:fail('%s is not an object that can be embedded', t.ref)
			end
		end

		function span_renderers.var(v,b,s)
			local val
			if v.pos then
				if not v.origin.invocation then
					v.origin:fail 'positional arguments can only be used in a macro invocation'
				elseif not v.origin.invocation.args[v.pos] then
					v.origin.invocation.origin:fail('macro invocation %s missing positional argument #%u', v.origin.invocation.macro, v.pos)
				end
				val = v.origin.invocation.args[v.pos]
			else
				val = v.origin.doc:context_var(v.var, v.origin)
			end
			if v.raw then
				return val
			else
				return htmlSpan(ct.parse_span(val, v.origin), b, s)
			end
		end

		function span_renderers.raw(v,b,s)
			return htmlSpan(v.spans, b, s)
		end

		function span_renderers.link(sp,b,s)
			local href
			if b.origin.doc.sections[sp.ref] then
				href = '#' .. sp.ref
			else
				if sp.addr then href = sp.addr else
					local r = b.origin:ref(sp.ref)
					if type(r) == 'table' then
						href = '#' .. getSafeID(r)
					else href = r end
				end
			end
			return tag('a',{href=href},next(sp.spans) and htmlSpan(sp.spans,b,s) or href)
		end

		span_renderers['line-break'] = function(sp,b,s)
			return elt('br')
		end

		function span_renderers.macro(m,b,s)
			local macroname = plainrdr.htmlSpan(
				ct.parse_span(m.macro, b.origin), b,s)
			local r = b.origin:ref(macroname)
			if type(r) ~= 'string' then
				b.origin:fail('%s is an object, not a reference', t.ref)
			end
			local mctx = b.origin:clone()
			mctx.invocation = m
			return htmlSpan(ct.parse_span(r, mctx),b,s)
		end
		function span_renderers.math(m,b,s)
			stylesNeeded.math = true
			return tag('span',{class='equation'},htmlSpan(m.spans, b, s))
		end;
		function span_renderers.directive(d,b,s)
			if d.ext == 'html' then
			elseif b.origin.doc:allow_ext(d.ext) then
			elseif d.crit then
				b.origin:fail('critical extension %s unavailable', d.ext)
			elseif d.failthru then
				return htmlSpan(d.spans, b, s)
			end
		end
		function span_renderers.footnote(f,b,s)
			stylesNeeded.footnote = true
			local source, sid, ssec = b.origin:ref(f.ref)
			local cnc = getSafeID(ssec) .. ' ' .. sid
			local fn
			if footnotes[cnc] then
				fn = footnotes[cnc]
			else
				footnotecount = footnotecount + 1
				fn = {num = footnotecount, origin = b.origin, fnid=cnc, source = source}
				fn.id = getSafeID(fn)
				footnotes[cnc] = fn
			end
			return tag('a', {href='#'..fn.id}, htmlSpan(f.spans) ..
						tag('sup',nil, fn.num))
		end

		return span_renderers
	end

	local function getBlockRenderers(procs, sr)
		local tag, elt, catenate = procs.tag, procs.elt, procs.catenate
		local null = function() return catenate{} end

		local block_renderers = {
			anchor = function(b,s)
				return tag('a',{id = getSafeID(b)},null())
			end;
			paragraph = function(b,s)
				stylesNeeded.paragraph = true;
				return tag('p', nil, sr.htmlSpan(b.spans, b, s), b)
			end;
			directive = function(b,s)
				-- deal with renderer directives
				local _, cmd, args = b.words(2)
				if cmd == 'page-title' then
					if not opts.title then doctitle = args end
				elseif b.critical then
					b.origin:fail('critical HTML renderer directive “%s” not supported', cmd)
				end
			end;
			label = function(b,s)
				if ct.sec.is(b.captions) then
					if not (opts['fossil-uv'] or opts.snippet) then
						stylesNeeded.header = true
					end
					local h = math.min(6,math.max(1,b.captions.depth))
					return tag(f('h%u',h), nil, sr.htmlSpan(b.spans, b, s), b)
				else
					-- handle other uses of labels here
				end
			end;
			['list-item'] = function(b,s)
				return tag('li', nil, sr.htmlSpan(b.spans, b, s), b)
			end;
			table = function(b,s)
				local tb = {}
				for i, r in ipairs(b.rows) do
					local row = {}
					for i, c in ipairs(r) do
						table.insert(row, tag(c.header and 'th' or 'td',
						{align=c.align}, sr.htmlSpan(c.spans, b)))
					end
					table.insert(tb, tag('tr',nil,catenate(row)))
				end
				return tag('table',nil,catenate(tb))
			end;
			listing = function(b,s)
				stylesNeeded.block_code_listing = true
				local nodes = ss.map(function(l)
					if #l > 0 then
						return tag('div',nil,sr.htmlSpan(l, b, s))
					else
						return elt('hr')
					end
				end, b.lines)
				if b.title then
					table.insert(nodes,1, tag('figcaption',nil,sr.htmlSpan(b.title)))
				end
				if b.lang then langsused[b.lang] = true end
				return tag('figure', {class='listing', lang=b.lang, id=b.id and getSafeID(b)}, catenate(nodes))
			end;
			aside = function(b,s)
				local bn = {}
				stylesNeeded.aside = true
				if #b.lines == 1 then
					bn[1] = sr.htmlSpan(b.lines[1], b, s)
				else
					for _,v in pairs(b.lines) do
						table.insert(bn, tag('p', {}, sr.htmlSpan(v, b, s)))
					end
				end
				return tag('aside', {}, bn)
			end;
			['break'] = function() -- HACK
				-- lists need to be rewritten to work like asides
				return '';
			end;
		}
		return block_renderers;
	end

	local function getRenderers(procs)
		local span_renderers = getSpanRenderers(procs)
		local r = getBaseRenderers(procs,span_renderers)
		r.block_renderers = getBlockRenderers(procs, r)
		return r
	end

	local astproc = {
		toHTML = getRenderers(tagproc.toHTML);
		toTXT  = getRenderers(tagproc.toTXT);
		toIR   = { };
	}
	astproc.toIR.span_renderers = ss.clone(astproc.toHTML);
	astproc.toIR.block_renderers = getBlockRenderers(tagproc.toIR,astproc.toHTML);
		-- note we use HTML here instead of IR span renderers, because as things
		-- currently stand we don't need that level of resolution. if we ever
		-- get to the point where we want to be able to twiddle spans around
		-- we'll need to introduce an IR span renderer

	render_state_handle.astproc = astproc;
	render_state_handle.tagproc = tagproc;

	-- bind to legacy names
	-- yikes this needs to be cleaned up so badly
	local ir = {}
	local dr = astproc.toHTML -- default renderers
	local plainr = astproc.toTXT
	local irBlockRdrs = astproc.toIR.block_renderers;

	render_state_handle.ir = ir;

	local function renderBlocks(blocks, irs)
		for i, block in ipairs(blocks) do
			local rd
			if irBlockRdrs[block.kind] then
				rd = irBlockRdrs[block.kind](block,sec)
			else
				local rdr = renderJob:proc('render',block.kind,'html')
				if rdr then
					rd = rdr({
						state = render_state_handle;
						tagproc = tagproc.toIR;
						astproc = astproc.toIR;
					}, block, sec)
				end
			end
			if rd then
				if opts['heading-anchors'] and block == sec.heading_node then
					stylesNeeded.headingAnchors = true
					table.insert(rd.nodes, ' ')
					table.insert(rd.nodes, {
						tag = 'a';
						attrs = {href = '#' .. irs.attrs.id, class='anchor'};
						nodes = {type(opts['heading-anchors'])=='string' and opts['heading-anchors'] or '&sect;'};
					})
				end
				if rd.src and rd.src.origin.lang then
					if not rd.attrs then rd.attrs = {} end
					rd.attrs.lang = rd.src.origin.lang
				end
				table.insert(irs.nodes, rd)
				runhook('ir_section_node_insert', rd, irs, sec)
			end
		end
	end
	runhook('ir_assemble', ir)
	for i, sec in ipairs(doc.secorder) do
		if doctitle == nil and sec.depth == 1 and sec.heading_node then
			doctitle = astproc.toTXT.htmlSpan(sec.heading_node.spans, sec.heading_node, sec)
		end
		local irs
		if sec.kind == 'ordinary' then
			if #(sec.blocks) > 0 then
				irs = {tag='section',attrs={id = getSafeID(sec)},nodes={}}
				runhook('ir_section_build', irs, sec)
				renderBlocks(sec.blocks, irs)
			end
		elseif sec.kind == 'blockquote' then
		elseif sec.kind == 'listing' then
		elseif sec.kind == 'embed' then
		end
		if irs then table.insert(ir, irs) end
	end

	for _, fn in pairs(footnotes) do
		local tag = tagproc.toIR.tag
		local body = {nodes={}}
		local ftir = {}
		for l in fn.source:gmatch('([^\n]*)') do
			ct.parse_line(l, fn.origin, ftir)
		end
		renderBlocks(ftir,body)
		local note = tag('div',{class='footnote',id=fn.id}, {
			tag('div',{class='number'}, tostring(fn.num)),
			tag('div',{class='text'}, body.nodes),
			tag('a',{href='#0'},'close')
		})
		table.insert(ir, note)
	end

	-- restructure passes
	runhook('ir_restructure_pre', ir)
	
	---- list insertion pass
	local lists = {}
	for _, sec in pairs(ir) do
		if sec.tag == 'section' then
			local i = 1 while i <= #sec.nodes do local v = sec.nodes[i]
				if v.tag == 'li' then
					local ltag
					if v.src.ordered
						then ltag = 'ol'
						else ltag = 'ul'
					end
					local last = i>1 and sec.nodes[i-1]
					if last and last.embed == 'list' and not (
						last.ref[#last.ref].src.depth   == v.src.depth and
						last.ref[#last.ref].src.ordered ~= v.src.ordered
					) then
						-- add to existing list
						table.insert(last.ref, v)
						table.remove(sec.nodes, i) i = i - 1
					else
						-- wrap in list
						local newls = {v}
						sec.nodes[i] = {embed = 'list', ref = newls}
						table.insert(lists,newls)
					end
				end
			i = i + 1 end
		end
	end

	for _, sec in pairs(ir) do
		if sec.tag == 'section' then
			for i, elt in pairs(sec.nodes) do
				if elt.embed == 'list' then
					local function fail_nest()
						elt.ref[1].src.origin:fail('improper list nesting')
					end
					local struc = {attrs={}, nodes={}}
					if elt.ref[1].src.ordered then struc.tag = 'ol' else struc.tag = 'ul' end
					if elt.ref[1].src.depth ~= 1 then fail_nest() end

					local stack = {struc}
					local copyNodes = function(old,new)
						for i,v in ipairs(old) do new[#new + i] = v end
					end
					for i,e in ipairs(elt.ref) do
						if e.src.depth > #stack then
							if e.src.depth - #stack > 1 then fail_nest() end
							local newls = {attrs={}, nodes={e}}
							copyNodes(e.nodes,newls)
							if e.src.ordered then newls.tag = 'ol' else newls.tag='ul' end
							table.insert(stack[#stack].nodes[#stack[#stack].nodes].nodes, newls)
							table.insert(stack, newls)
						else
							if e.src.depth < #stack then
								-- pop entries off the stack
								for i=#stack, e.src.depth+1, -1 do stack[i] = nil end
							end
							table.insert(stack[#stack].nodes, e)
						end
					end

					sec.nodes[i] = struc
				end
			end
		end
	end
	
	runhook('ir_restructure_post', ir)

	-- collection pass
	local function collect_nodes(t)
		local ts = ''
		for i,v in ipairs(t) do
			if type(v) == 'string' then
				ts = ts .. v
			elseif v.nodes then
				ts = ts .. tagproc.toHTML.tag(v.tag, v.attrs, collect_nodes(v.nodes))
			elseif v.text then
				ts = ts .. tagproc.toHTML.tag(v.tag,v.attrs,v.text)
			else
				ts = ts .. tagproc.toHTML.elt(v.tag,v.attrs)
			end
		end
		return ts
	end
	local body = collect_nodes(ir)

	for k in pairs(langsused) do
		local spec = langpairs[k] or {color=0xaaaaaa}
		stylesets.block_code_listing = stylesets.block_code_listing .. string.format(
			[[section > figure.listing[lang="%s"]>figcaption::after
				{ content: '%s'; color: #%06x }]],
			k, spec.name or k, spec.color)
	end

	local prepcss = function(css)
		local tone = function(fac, sat, sep, alpha)
			local hsl = function(h,s,l,a)
				local v = string.format('%s, %u%%, %u%%', h,s,l)
				if a then
					return string.format('hsla(%s, %s)', v,a)
				else
					return string.format('hsl(%s)', v)
				end
			end
			sat = sat or 1
			fac = math.max(math.min(fac, 1), 0)
			sat = math.max(math.min(sat, 1), 0)
			if opts.accent then
				local hue = 'var(--accent)'
				local hsep = tonumber(opts['hue-spread'])
				if hsep and sep and sep ~= 0 then
					hue = string.format('calc(%s - %s)', hue, sep * hsep)
				end
				return hsl(hue, math.floor(100*sat), math.floor(100*fac), alpha)
			else
				local g = math.floor(0xFF * fac)
				return string.format('#' .. string.rep('%02x',alpha and 4 or 3), g,g,g,alpha and math.floor(0xFF*alpha))
			end
		end
		local replace = function(var,alpha,param)
			local tonespan = opts.accent and .1 or 0
			local tbg = opts['dark-on-light'] and 1.0 - tonespan or tonespan
			local tfg = opts['dark-on-light'] and tonespan or 1.0 - tonespan
			if var == 'bg' then
				return tone(tbg,nil,nil,tonumber(alpha))
			elseif var == 'fg' then
				return tone(tfg,nil,nil,tonumber(alpha))
			elseif var == 'width' then
				return opts['width'] or '100vw'
			elseif var == 'tone' then
				local l, sep, sat
				for i=1,3 do -- 🙄
					l,sep,sat = param:match('^%('..string.rep('([^%s]*)%s*',i)..'%)$')
					if l then break end
				end
				l = ss.math.lerp(tonumber(l), tbg, tfg)
				return tone(l, tonumber(sat), tonumber(sep), tonumber(alpha))
			end
		end
		css = css:gsub('@(%b[]):(%b[])', function(v,d) return opts[v:sub(2,-2)] or v:sub(2,-2) end)
		css = css:gsub('@(%w+)/([0-9.]+)(%b())', replace)
		css = css:gsub('@(%w+)(%b())', function(a,b) return replace(a,nil,b) end)
		css = css:gsub('@(%w+)/([0-9.]+)', replace)
		css = css:gsub('@(%w+)', function(a,b) return replace(a,nil,b) end)
		return (css:gsub('%s+',' '))
	end

	local styles = {}
	if opts.width then
		table.insert(styles, string.format([[body {padding:0 1em;margin:auto;max-width:%s}]], opts.width))
	end
	if opts.accent then
		table.insert(styles, string.format(':root {--accent:%s}', opts.accent))
	end
	if opts.accent or (not opts['dark-on-light']) and (not opts['fossil-uv']) then
		stylesNeeded.accent = true
	end


	for k in pairs(stylesNeeded) do
		if not stylesets[k] then ct.exns.unimpl('styleset %s not implemented (!)',  k):throw() end
		table.insert(styles, prepcss(stylesets[k]))
	end

	local head = {}
	local styletag = ''
	if opts['link-css'] then
		local css = opts['link-css']
		if type(css) ~= 'string' then ct.exns.mode('must be a string', 'html:link-css'):throw() end
		styletag = styletag .. tagproc.toHTML.elt('link',{rel='stylesheet',type='text/css',href=opts['link-css']})
	end
	if next(styles) then
		if opts['gen-styles'] then
			styletag = styletag .. tagproc.toHTML.tag('style',{type='text/css'},table.concat(styles))
		end
		table.insert(head, styletag)
	end

	if opts['fossil-uv'] then
		return tagproc.toHTML.tag('div',{class='fossil-doc',['data-title']=doctitle},styletag .. body)
	elseif opts.snippet then
		return styletag .. body
	else
		return dr.htmlDoc(doctitle, next(head) and table.concat(head), body)
	end
end

do -- define span control sequences
	local function formatter(sty)
		return function(s,c)
			return {
				kind = 'format';
				style = sty;
................................................................................
				end
				return r
			end)
			local m = {s} --TODO
			return {
				kind = 'math';
				original = s;
				spans = m;
				origin = c:clone();
			};
		end};
		{seq = '&', parse = function(s, c)
			local r, t = s:match '^([^%s]+)%s*(.-)$'
			return {
				kind = 'deref';
				spans = (t and t ~= "") and ct.parse_span(t, c) or {};
				ref = r; 
				origin = c:clone();
			}
		end};
		{seq = '^', parse = function(s, c)
			local fn, t = s:match '^([^%s]+)%s*(.-)$'
			return {
				kind = 'footnote';
................................................................................
			table.insert(spans,o)
		elseif c == '[' then
			flush()
			local substr, following = delimited('[',']',str:sub(p.byte))
			p.next.byte = following + p.byte
			local found = false
			for _,i in pairs(ct.spanctls) do
				if startswith(substr, i.seq) then
					found = true
					table.insert(spans, i.parse(substr:sub(1+#i.seq), ctx))
					break
				end
			end
			if not found then
				ctx:fail('no recognized control sequence in [%s]', substr)

				table.insert(ret, (hookfn(me:delegate(ext),...)))
			end
			return ret
		end;
	};
}

-- common renderer utility functions
ct.tool = {}


function ct.tool.mathfmt(ctx, eqn)
	local buf = ''
	local m = ss.enum {'num','var','op'}
	local lsc = 0
	local spans = {}

	local flush = function()
		local o
		if buf ~= '' then
			if lsc == 0 then
				o = buf
			elseif lsc == m.num then
				o = {
					kind = 'format';
					style = 'literal';
					spans = {buf};
				}
			elseif lsc == m.var then
				o = {
					kind = 'format';
					style = 'variable';
					spans = {buf};
				}
			elseif lsc == m.op then
				o = {
					kind = 'format';
					style = 'strong';
					spans = {buf};
				}
			end
			if o then
				table.insert(spans, o)
			end
		end
		buf = ''
		lsc = 0
	end

	for c, p in ss.str.each(ctx.doc.enc, eqn) do
		local cl = ss.str.classify(ctx.doc.enc, c)
		local nc = 0
		if not cl.space then
			if cl.numeral then
				nc = m.num
			elseif cl.mathop or cl.symbol then
				nc = m.op
			elseif cl.letter then
				nc = m.var
			end
			if nc ~= lsc then
				flush()
				lsc = nc
			end
			buf = buf .. c
		end
	end
	flush()
	return spans
end

function ct.tool.namespace()
-- some renderers need to be able to generate unique IDs for
-- objects, including ones that users have not assigned IDs
-- to, and objects with the same name in different unlabeled
-- sections. to handle this, we provide a "namespace" mechanism,
-- where some lua table (really its address in memory) is used
-- as a handle for the object and a unique ID is attached to it.
-- if the object has an ID of its own, it is guaranteed to be
-- unique and returned; otherwise, a generic id of the form
-- `x-%u` is generated, where %u is an integer that increments
-- for every new object
	local ids = {}
	local canonicalID = {}

	return function(obj,pfx)
		pfx = pfx or ''
		if canonicalID[obj] then
			return canonicalID[obj]
		elseif obj.id and ids[pfx .. obj.id] then
			local objid = pfx .. obj.id
			local newid
			local i = 1
................................................................................
					i = i + 1 until not ids[cid]
			end
			ids[cid] = obj
			canonicalID[obj] = cid
			return cid
		end
	end






























































































































































































































































































































end




















































































































































































































-- renderer engines
























































































































































































































































































































































































do -- define span control sequences
	local function formatter(sty)
		return function(s,c)
			return {
				kind = 'format';
				style = sty;
................................................................................
				end
				return r
			end)
			local m = {s} --TODO
			return {
				kind = 'math';
				original = s;
				spans = {s};
				origin = c:clone();
			};
		end};
		{seq = '&', parse = function(s, c)
			local r, t = s:match '^([^%s]+)%s*(.-)$'
			return {
				kind = 'deref';
				spans = (t and t ~= "") and ct.parse_span(t, c) or {};
				ref = r;
				origin = c:clone();
			}
		end};
		{seq = '^', parse = function(s, c)
			local fn, t = s:match '^([^%s]+)%s*(.-)$'
			return {
				kind = 'footnote';
................................................................................
			table.insert(spans,o)
		elseif c == '[' then
			flush()
			local substr, following = delimited('[',']',str:sub(p.byte))
			p.next.byte = following + p.byte
			local found = false
			for _,i in pairs(ct.spanctls) do
				if ss.str.begins(substr, i.seq) then
					found = true
					table.insert(spans, i.parse(substr:sub(1+#i.seq), ctx))
					break
				end
			end
			if not found then
				ctx:fail('no recognized control sequence in [%s]', substr)