1 files changed, 87 insertions, 0 deletions
diff --git a/html.lua b/html.lua
new file mode 100644
index 0000000..87ecc53
--- /dev/null
+++ b/html.lua
@@ -0,0 +1,87 @@
+local function fmt_attrs(attrs)
+	local function fmt_attr(k,v)
+		if v == true then
+			return k
+		else
+			if type(v) == "table" then v = table.concat(v," ") end
+			return ('%s="%s"'):format(k,v)
+		end
+	end
+
+	local o = ""
+	for k,v in pairs(attrs) do
+		o = o .. " " .. fmt_attr(k,v)
+	end
+	return o
+end
+
+local html
+local function fmt_tag(tag)
+	local attrs = tag.attrs and fmt_attrs(tag.attrs) or ""
+	local selfclosing = (tag.body == "")
+	local sameline = type(tag.body) == "string" or (type(tag.body) == "table" and tag.body.tag)
+	local maybenl = sameline and "" or "\n"
+	if selfclosing then
+		return ("<%s%s/>"):format(tag.tname,attrs)
+	else
+		return ("<%s%s>%s%s</%s>"):format(tag.tname,attrs,maybenl,html(tag.body),tag.tname)
+	end
+end
+
+local function tag(tname, a1, a2)
+	-- tag(tname,body) or tag(tname,attrs,body)
+	local body, attrs
+	if a2 then attrs=a1 body=a2 else attrs=nil body=a1 end
+	return setmetatable({tag=true,tname=tname,attrs=attrs,body=body},{__tostring=fmt_tag})
+end
+
+-- instead of tag('ul', {x, y, z})
+-- you can do T.ul{ x, y, z}
+local T = setmetatable({}, {__index=function(_,tname)
+	return function (...)
+		return tag(tname, ...)
+	end
+end})
+
+local function safe(s)
+	-- marks s as safe, doesn't escape it
+	assert(type(s) == "string","can only mark string as safe")
+	return setmetatable({safe=true,s=s},{__tostring=function(x)return x.s end})
+end
+
+local function escape(s)
+	s=s:gsub("&","&amp;")
+	s=s:gsub("<","&lt;")
+	s=s:gsub(">","&gt;")
+	s=s:gsub('"',"&quot;")
+	return safe(s)
+end
+
+
+html = function (x)
+	if type(x) == "string" then
+		return escape(x)
+	elseif type(x) == "table" then
+		if x.safe then
+			-- safestr. already escaped
+			return x
+		elseif x.tag then
+			-- it's a tag
+			return safe( tostring(x) )
+		else
+			-- just a regular list
+			local o = ""
+			for _,item in ipairs(x) do
+				o = o .. tostring(html(item)) .. "\n"
+			end
+			return safe(o)
+		end
+	end
+end
+
+return {
+	html = html,
+	tag = tag,
+	safe = safe,
+	T = T,
+}