implement sed plugin

plugins/sed.lua

@@ -0,0 +1,148 @@
+local LastMessage = {}
+
+-- Meeeeh.
+local function esc(x)
+   return (x:gsub('%%', '%%%%')
+            :gsub('^%^', '%%^')
+            :gsub('%$$', '%%$')
+            :gsub('%(', '%%(')
+            :gsub('%)', '%%)')
+            :gsub('%.', '%%.')
+            :gsub('%[', '%%[')
+            :gsub('%]', '%%]')
+            :gsub('%*', '%%*')
+            :gsub('%+', '%%+')
+            :gsub('%-', '%%-')
+            :gsub('%?', '%%?'))
+end
+
+local memoize = function(Username, Channel, Message)
+	if LastMessage[Channel] == nil then
+		LastMessage[Channel] = {}
+	end
+
+	LastMessage[Channel][Username] = Message
+end
+
+local sed = function(Username, Channel, Message)
+	if LastMessage[Channel] == nil then
+		return
+	end
+	if LastMessage[Channel][Username] == nil then
+		return
+	end
+	local Last = LastMessage[Channel][Username]
+
+	if #Message < 4 then
+		return
+	end
+
+	local Delim = Message:sub(2,2)
+
+	if Message:sub(1,1) ~= "s" then
+		return
+	end
+
+	local Global = false
+	local Inner = Message:sub(3, -2)
+	if #Message > 4 and Message:sub(-2, -1) == (Delim .. "g") then
+		Global = true
+		Inner = Message:sub(3,-3)
+	elseif Message:sub(-1,-1) ~= Delim then
+		return
+	end
+
+	if #Inner < 1 then
+		return
+	end
+
+	-- Meh.
+	local First = ""
+	local Second = ""
+	local Found = false
+	for i = 0, #Inner do
+		local Cur = Inner:sub(i, i)
+		if not Found then
+			if Cur == Delim then
+				Found = true
+			else
+				First = First .. Cur
+		    	end
+		else
+			if Cur == Delim then
+				return
+			else
+				Second = Second .. Cur
+			end
+		end
+	end
+
+	if #First < 1 then
+		return
+	end
+
+	local n = 1
+	if Global then
+		n = nil
+	end
+	local Replaced = Last:gsub(esc(First), Second, n)
+	Channel:Say(Username .. " meant " .. Replaced)
+
+	-- memoize corrected version
+	memoize(Username, Channel, Replaced)
+
+	return true
+end
+
+local Test = false
+-- Mun runtime has no pcall, detect this way.
+if plugin == nil then
+	Test = true
+end
+
+if Test then
+	local Channel = {}
+	Channel.Say = function(chan, What)
+		chan.Said = What
+	end
+
+	local mustEqual = function(a, b)
+		if a ~= b then
+			print(tostring(a) .. " != " .. tostring(b))
+		end
+	end
+
+	memoize("q3k", Channel, "lorem ipsum dolor sit amet")
+	sed("q3k", Channel, "s,ipsum,foo,")
+	mustEqual(Channel.Said, "q3k meant lorem foo dolor sit amet")
+	Channel.Said = nil
+
+	memoize("q3k", Channel, "lorem ipsum dolor sit amet")
+	sed("q3k", Channel, "s,ipsum,foo/")
+	mustEqual(Channel.Said, nil)
+	sed("q3k", Channel, "s/no/don/t/")
+	mustEqual(Channel.Said, nil)
+	sed("q3k", Channel, "s///")
+	mustEqual(Channel.Said, nil)
+	sed("q3k", Channel, "s//")
+	mustEqual(Channel.Said, nil)
+
+	Channel.Said = nil
+	memoize("q3k", Channel, "barfoo barbaz foobar")
+	sed("q3k", Channel, "s/foo/what/g")
+	mustEqual(Channel.Said, "q3k meant barwhat barbaz whatbar")
+
+	Channel.Said = nil
+	memoize("q3k", Channel, "barfoo barbaz foobar")
+	sed("q3k", Channel, "s/foo/what/")
+	mustEqual(Channel.Said, "q3k meant barwhat barbaz foobar")
+
+	print("ok")
+else
+	plugin.AddHook("irc.Message", "sed", function(Username, Channel, Message)
+		local replaced = sed(Username, Channel, Message)
+		if not replaced then
+			memoize(Username, Channel, Message)
+		end
+	end)
+end