Add trie

init.lua

@@ -67,7 +67,8 @@ local components = {
     table = {},
     text = {string = "local"},
     threading = {},
-    vector = {}
+    vector = {},
+    trie = {}
 }
 
 modlib = {}

trie.lua

@@ -0,0 +1,121 @@
+local trie = getfenv(1)
+
+function new(table) return setmetatable(table or {}, trie) end
+
+function insert(self, word, value, overwrite)
+	for i = 1, word:len() do
+		local char = word:sub(i, i)
+		self[char] = self[char] or {}
+		self = self[char]
+	end
+	local previous_value = self.value
+	if not previous_value or overwrite then self.value = value or true end
+	return previous_value
+end
+
+function remove(self, word)
+	local branch, character = self, word:sub(1, 1)
+	for i = 1, word:len() - 1 do
+		local char = word:sub(i, i)
+		if not self[char] then return end
+		if self[char].value or next(self, next(self)) then
+			branch = self
+			character = char
+		end
+		self = self[char]
+	end
+	local char = word:sub(word:len())
+	if not self[char] then return end
+	self = self[char]
+	local previous_value = self.value
+	self.value = nil
+	if branch and not next(self) then branch[character] = nil end
+	return previous_value
+end
+
+--> value if found
+--> nil else
+function get(self, word)
+	for i = 1, word:len() do
+		local char = word:sub(i, i)
+		self = self[char]
+		if not self then return end
+	end
+	return self.value
+end
+
+function suggestion(self, remainder)
+	local until_now = {}
+	local subtries = { [self] = until_now }
+	local suggestion, value
+	while next(subtries) do
+		local new_subtries = {}
+		local leaves = {}
+		for trie, word in pairs(subtries) do
+			if trie.value then table.insert(leaves, { word = word, value = trie.value }) end
+		end
+		if #leaves > 0 then
+			if remainder then
+				local best_leaves = {}
+				local best_score = 0
+				for _, leaf in pairs(leaves) do
+					local score = 0
+					for i = 1, math.min(#leaf.word, string.len(remainder)) do
+						-- calculate intersection
+						if remainder:sub(i, i) == leaf.word[i] then score = score + 1 end
+					end
+					if score == best_score then table.insert(best_leaves, leaf)
+					elseif score > best_score then best_leaves = { leaf } end
+				end
+				leaves = best_leaves
+			end
+			-- TODO select best instead of random
+			local leaf = leaves[math.random(1, #leaves)]
+			suggestion, value = table.concat(leaf.word), leaf.value
+			break
+		end
+		for trie, word in pairs(subtries) do
+			for char, subtrie in pairs(trie) do
+				local word = { unpack(word) }
+				table.insert(word, char)
+				new_subtries[subtrie] = word
+			end
+		end
+		subtries = new_subtries
+	end
+	return suggestion, value
+end
+
+--> value if found
+--> nil, suggestion, value of suggestion else
+function search(self, word)
+	for i = 1, word:len() do
+		local char = word:sub(i, i)
+		if not self[char] then
+			local until_now = word:sub(1, i - 1)
+			local suggestion, value = suggestion(self, word:sub(i))
+			return nil, until_now .. suggestion, value
+		end
+		self = self[char]
+	end
+	local value = self.value
+	if value then return value end
+	local until_now = word
+	local suggestion, value = suggestion(self)
+	return nil, until_now .. suggestion, value
+end
+
+function find_longest(self, query, query_offset)
+	local leaf_pos = query_offset
+	local last_leaf
+	for i = query_offset, query:len() do
+		local char = query:sub(i, i)
+		self = self[char]
+		if not self then break
+		elseif self.value then
+			last_leaf = self.value
+			leaf_pos = i
+		end
+	end
+	return last_leaf, leaf_pos
+end