149 lines
3.7 KiB
Lua
149 lines
3.7 KiB
Lua
-- This file implements equivalents of various higher-order WFL functions
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local functional = {}
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function functional.filter(input, condition)
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local filtered_table = {}
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for _,v in ipairs(input) do
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if condition(v) then
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table.insert(filtered_table, v)
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end
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end
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return filtered_table
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end
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function functional.filter_map(input, condition)
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local filtered_table = {}
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for k,v in pairs(input) do
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if condition(k, v) then
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filtered_table[k] = v
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end
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end
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return filtered_table
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end
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function functional.find(input, condition)
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for _,v in ipairs(input) do
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if condition(v) then
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return v
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end
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end
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end
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function functional.find_map(input, condition)
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for k,v in pairs(input) do
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if condition(k,v) then
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return k, v
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end
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end
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end
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function functional.choose(input, value)
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-- Equivalent of choose() function in Formula AI
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-- Returns element of a table with the largest @value (a function)
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-- Also returns the max value and the index
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local max_value, best_input, best_key = -math.huge
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for k,v in ipairs(input) do
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local v2 = value(v)
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if v2 > max_value then
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max_value, best_input, best_key = v2, v, k
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end
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end
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return best_input, max_value, best_key
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end
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function functional.choose_map(input, value)
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-- Equivalent of choose() function in Formula AI
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-- Returns element of a table with the largest @value (a function)
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-- Also returns the max value and the index
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local max_value, best_input, best_key = -math.huge
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for k,v in pairs(input) do
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local v2 = value(k, v)
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if v2 > max_value then
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max_value, best_input, best_key = v2, v, k
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end
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end
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return {key = best_key, value = best_input}, max_value
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end
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function functional.map(input, formula)
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local mapped_table = {}
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for k,v in pairs(input) do
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if type(k) == 'number' then
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table.insert(mapped_table, formula(v))
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else
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mapped_table[k] = formula(v, k)
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end
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end
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return mapped_table
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end
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local known_operators = {
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['+'] = function(a, b) return a + b end,
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['-'] = function(a, b) return a - b end,
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['*'] = function(a, b) return a * b end,
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['/'] = function(a, b) return a / b end,
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['%'] = function(a, b) return a % b end,
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['^'] = function(a, b) return a ^ b end,
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['//'] = function(a, b) return a // b end,
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['&'] = function(a, b) return a & b end,
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['|'] = function(a, b) return a | b end,
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['~'] = function(a, b) return a ~ b end,
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['<<'] = function(a, b) return a << b end,
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['>>'] = function(a, b) return a >> b end,
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['..'] = function(a, b) return a .. b end,
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['=='] = function(a, b) return a == b end,
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['~='] = function(a, b) return a ~= b end,
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['<'] = function(a, b) return a < b end,
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['>'] = function(a, b) return a > b end,
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['<='] = function(a, b) return a <= b end,
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['>='] = function(a, b) return a >= b end,
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['and'] = function(a, b) return a and b end,
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['or'] = function(a, b) return a or b end,
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}
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function functional.reduce(input, operator, identity)
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if type(operator) == 'string' then
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operator = known_operators[operator]
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end
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local result = identity or 0
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for _, v in ipairs(input) do
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result = operator(result, v)
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end
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return result
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end
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function functional.take_while(input, condition)
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local truncated_table = {}
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for _,v in ipairs(input) do
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if not condition(v) then
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break
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end
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table.insert(truncated_table, v)
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end
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return truncated_table
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end
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-- Technically not a higher-order function, but whatever...
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function functional.zip(input)
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local output = {}
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local _, n = functional.choose(input, function(list) return #list end)
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for i = 1, n do
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local elem = {}
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for j, list in ipairs(input) do
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elem[j] = list[i]
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end
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table.insert(output, elem)
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end
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return output
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end
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return functional
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