1 files changed, 90 insertions, 0 deletions
diff --git a/prose.lua b/prose.lua
new file mode 100644
index 0000000..ceadec0
--- /dev/null
+++ b/prose.lua
@@ -0,0 +1,90 @@
+local html = require'html'
+
+local extensions = {}
+
+local function prose(S, text)
+	-- this may be a hack
+	local replacements = {}
+	local SO, SI = "\x0e", "\x0f"
+	-- if debugview then SO,SI = "\x1b[7m", "\x1b[0m" end
+	local function emplace(s)
+		table.insert(replacements, s)
+		return SO .. #replacements .. SI
+	end
+
+	-- no way to match 'after ws or at start of string'
+	-- so, just add ws to start and end of string
+	-- this may also be a hack
+	text = ' ' .. text .. ' '
+
+	local function simple_sub(delim, tagname)
+		return {
+			"(%s)"..delim..'(.-)'..delim..'(%W)', -- wo wimple
+			function(a,x,b) return a..emplace(html.T[tagname](x))..b end
+		}
+	end
+
+	local function extension(str)
+		local verb, rest = str:match("^{(%w+);%s*(.*)}$")
+		if verb then
+			return emplace(extensions[verb](S, rest))
+		end
+		local verbonly = str:match("^{(%w+)}$")
+		if verbonly then
+			return emplace(extensions[verbonly](S))
+		end
+		error("invalid extension syntax: "..str)
+	end
+
+	local subs = {
+		{ "%b{}", extension },
+		simple_sub('%*', 'strong'),
+		simple_sub('_', 'em'),
+		simple_sub('`', 'code'),
+	}
+
+	for i, row in ipairs(subs) do
+		local pattern,replacement = row[1], row[2]
+		text = text:gsub(pattern,replacement)
+	end
+
+	text = text:gsub("^%s*",""):gsub("%s*$","")
+	-- print(text)
+	local insects = {""}
+	local n = 1
+	while n <= #text do
+		local _, nn, id = text:find('^'..SO:gsub("%[","%%[").."(%d+)"..SI:gsub("%[","%%["), n)
+		if nn then
+			table.insert(insects, replacements[tonumber(id)])
+			table.insert(insects, "")
+			n = nn + 1
+		else
+			local c = text:sub(n,n)
+			-- print("'"..c.."'")
+			insects[#insects] = insects[#insects] .. c
+			n = n + 1
+		end
+	end
+
+	-- for i,n in ipairs(insects) do print(i,type(n),n) end
+
+	return insects
+end
+
+extensions.fn = function(S,text)
+	S.footnotes = S.footnotes or {}
+	local n = #S.footnotes + 1
+	local link_id = "fnref_"..n
+	local note_id = "fn_"..n
+	S.footnotes[n] = html.T.li({id=note_id}, {
+		prose(S,text), html.safe"&nbsp;",
+		html.T.a({href="#"..link_id, role="doc-backlink"}, html.safe"&#x21a9;&#xfe0e;")})
+	return html.T.sup({id=link_id}, html.T.a({href="#"..note_id, role='doc-noteref'}, '('..n..')'))
+end
+
+extensions.fns = function(S)
+	if not S.footnotes then return "" end
+	return {html.T.hr{}, html.T.ol(S.footnotes)}
+end
+
+return prose