More powerful chat text templating available

game/engines/default/engine/Chat.lua

@@ -19,6 +19,7 @@
 
 require "engine.class"
 require "engine.dialogs.Chat"
+local slt2 = require "slt2"
 
 --- Handle chats between the player and NPCs
 module(..., package.seeall, class.make)
@@ -30,6 +31,7 @@ function _M:init(name, npc, player, data)
 	self.player = player
 	self.name = name
 	data = setmetatable(data or {}, {__index=_G})
+	self.data = data
 
 	local f, err = loadfile("/data/chats/"..name..".lua")
 	if not f and err then error(err) end
@@ -53,7 +55,7 @@ function _M:addChat(c)
 	self:triggerHook{"Chat:add", c=c}
 
 	assert(c.id, "no chat id")
-	assert(c.text, "no chat text")
+	assert(c.text or c.template, "no chat text or template")
 	assert(c.answers, "no chat answers")
 	self.chats[c.id] = c
 	print("[CHAT] loaded", c.id, c)
@@ -81,7 +83,12 @@ end
 
 --- Gets the chat with the given id
 function _M:get(id)
-	return self.chats[id]
+	local c = self.chats[id]
+	if c and c.template then
+		local tpl = slt2.loadstring(c.template)
+		c.text = slt2.render(tpl, {data=self.data, player=self.player, npc=self.npc})
+	end
+	return c
 end
 
 --- Replace some keywords in the given text

game/thirdparty/slt2.lua

+--[[
+-- slt2 - Simple Lua Template 2
+--
+-- Project page: https://github.com/henix/slt2
+--
+-- @License
+-- MIT License
+--]]
+
+local slt2 = {}
+
+-- a tree fold on inclusion tree
+-- @param init_func: must return a new value when called
+local function include_fold(template, start_tag, end_tag, fold_func, init_func)
+	local result = init_func()
+
+	start_tag = start_tag or '<?'
+	end_tag = end_tag or '?>'
+	local start_tag_inc = start_tag..'include:'
+
+	local start1, end1 = string.find(template, start_tag_inc, 1, true)
+	local start2 = nil
+	local end2 = 0
+
+	while start1 ~= nil do
+		if start1 > end2 + 1 then -- for beginning part of file
+			result = fold_func(result, string.sub(template, end2 + 1, start1 - 1))
+		end
+		start2, end2 = string.find(template, end_tag, end1 + 1, true)
+		assert(start2, 'end tag "'..end_tag..'" missing')
+		do -- recursively include the file
+			local filename = assert(loadstring('return '..string.sub(template, end1 + 1, start2 - 1)))()
+			assert(filename)
+			local fin = assert(io.open(filename))
+			-- TODO: detect cyclic inclusion?
+			result = fold_func(result, include_fold(fin:read('*a'), start_tag, end_tag, fold_func, init_func), filename)
+			fin:close()
+		end
+		start1, end1 = string.find(template, start_tag_inc, end2 + 1, true)
+	end
+	result = fold_func(result, string.sub(template, end2 + 1))
+	return result
+end
+
+-- preprocess included files
+-- @return string
+function slt2.precompile(template, start_tag, end_tag)
+	return table.concat(include_fold(template, start_tag, end_tag, function(acc, v)
+		if type(v) == 'string' then
+			table.insert(acc, v)
+		elseif type(v) == 'table' then
+			table.insert(acc, table.concat(v))
+		else
+			error('Unknown type: '..type(v))
+		end
+		return acc
+	end, function() return {} end))
+end
+
+-- unique a list, preserve order
+local function stable_uniq(t)
+	local existed = {}
+	local res = {}
+	for _, v in ipairs(t) do
+		if not existed[v] then
+			table.insert(res, v)
+			existed[v] = true
+		end
+	end
+	return res
+end
+
+-- @return { string }
+function slt2.get_dependency(template, start_tag, end_tag)
+	return stable_uniq(include_fold(template, start_tag, end_tag, function(acc, v, name)
+		if type(v) == 'string' then
+		elseif type(v) == 'table' then
+			if name ~= nil then
+				table.insert(acc, name)
+			end
+			for _, subname in ipairs(v) do
+				table.insert(acc, subname)
+			end
+		else
+			error('Unknown type: '..type(v))
+		end
+		return acc
+	end, function() return {} end))
+end
+
+-- @return { name = string, code = string / function}
+function slt2.loadstring(template, start_tag, end_tag, tmpl_name)
+	-- compile it to lua code
+	local lua_code = {}
+
+	start_tag = start_tag or '<?'
+	end_tag = end_tag or '?>'
+
+	local output_func = "coroutine.yield"
+
+	template = slt2.precompile(template, start_tag, end_tag)
+
+	local start1, end1 = string.find(template, start_tag, 1, true)
+	local start2 = nil
+	local end2 = 0
+
+	local cEqual = string.byte('=', 1)
+
+	while start1 ~= nil do
+		if start1 > end2 + 1 then
+			table.insert(lua_code, output_func..'('..string.format("%q", string.sub(template, end2 + 1, start1 - 1))..')')
+		end
+		start2, end2 = string.find(template, end_tag, end1 + 1, true)
+		assert(start2, 'end_tag "'..end_tag..'" missing')
+		if string.byte(template, end1 + 1) == cEqual then
+			table.insert(lua_code, output_func..'('..string.sub(template, end1 + 2, start2 - 1)..')')
+		else
+			table.insert(lua_code, string.sub(template, end1 + 1, start2 - 1))
+		end
+		start1, end1 = string.find(template, start_tag, end2 + 1, true)
+	end
+	table.insert(lua_code, output_func..'('..string.format("%q", string.sub(template, end2 + 1))..')')
+
+	local ret = { name = tmpl_name or '=(slt2.loadstring)' }
+	if setfenv == nil then -- lua 5.2
+		ret.code = table.concat(lua_code, '\n')
+	else -- lua 5.1
+		ret.code = assert(loadstring(table.concat(lua_code, '\n'), ret.name))
+	end
+	return ret
+end
+
+-- @return { name = string, code = string / function }
+function slt2.loadfile(filename, start_tag, end_tag)
+	local fin = assert(io.open(filename))
+	local all = fin:read('*a')
+	fin:close()
+	return slt2.loadstring(all, start_tag, end_tag, filename)
+end
+
+local mt52 = { __index = _ENV }
+local mt51 = { __index = _G }
+
+-- @return a coroutine function
+function slt2.render_co(t, env)
+	local f
+	if setfenv == nil then -- lua 5.2
+		if env ~= nil then
+			setmetatable(env, mt52)
+		end
+		f = assert(load(t.code, t.name, 't', env or _ENV))
+	else -- lua 5.1
+		if env ~= nil then
+			setmetatable(env, mt51)
+		end
+		f = setfenv(t.code, env or _G)
+	end
+	return f
+end
+
+-- @return string
+function slt2.render(t, env)
+	local result = {}
+	local co = coroutine.create(slt2.render_co(t, env))
+	while coroutine.status(co) ~= 'dead' do
+		local ok, chunk = coroutine.resume(co)
+		if not ok then
+			error(chunk)
+		end
+		table.insert(result, chunk)
+	end
+	return table.concat(result)
+end
+
+return slt2