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