function t.map(s,Q)assert(t.callback(s),t.callback(Q))local w=t.keys(s)local A=t.values(Q)return function(s)local Q,t=w(s)if not Q then return false,t or""end local x,M=A(s)if not x then return false,M or""end return true end end do local s=t.keys(t.integer)function t.array(Q)assert(t.callback(Q))local w=t.values(Q)return function(Q)local t,A=s(Q)if t==false then return false,string.format("\091\097\114\114\097\121\093 \037\115",A or"")end local x=0 for s in ipairs(Q)do x=x+1 end for s in pairs(Q)do if s<1 or s>x then return false,string.format("\091\097\114\114\097\121\093 \107\101\121 \037\115 \109\117\115\116 \098\101 \115\101\113\117\101\110\116\105\097\108",tostring(s))end end local M,O=w(Q)if not M then return false,string.format("\091\097\114\114\097\121\093 \037\115",O or"")end return true end end end do local s=t.array(t.callback)function t.union(...)local Q={...}assert(s(Q))return function(s)for Q,w in ipairs(Q)do if w(s)then return true end end return false,"\098\097\100 \116\121\112\101 \102\111\114 \117\110\105\111\110"end end t.some=t.union function t.intersection(...)local Q={...}assert(s(Q))return function(s)for Q,w in ipairs(Q)do local t,A=w(s)if not t then return false,A or""end end return true end end t.every=t.intersection end do local s=t.map(t.any,t.callback)function t.interface(Q)assert(s(Q))return function(s)local w,A=t.table(s)if w==false then return false,A or""end for Q,w in pairs(Q)do local t,A=w(s[Q])if t==false then return false,string.format("\091\105\110\116\101\114\102\097\099\101\093 \098\097\100 \118\097\108\117\101 \102\111\114 \037\115\058\n\t\037\115",tostring(Q),A or"")end end return true end end function t.strictInterface(Q)assert(s(Q))return function(s)local w,A=t.table(s)if w==false then return false,A or""end for Q,w in pairs(Q)do local t,A=w(s[Q])if t==false then return false,string.format("\091\105\110\116\101\114\102\097\099\101\093 \098\097\100 \118\097\108\117\101 \102\111\114 \037\115\058\n\t\037\115",tostring(Q),A or"")end end for s in pairs(s)do if not Q[s]then return false,string.format("\091\105\110\116\101\114\102\097\099\101\093 \117\110\101\120\112\101\099\116\101\100 \102\105\101\108\100 \037\113",tostring(s))end end return true end end end

function t.map(keyCheck, valueCheck)
	assert(t.callback(keyCheck), t.callback(valueCheck))
	local keyChecker = t.keys(keyCheck)
	local valueChecker = t.values(valueCheck)

	return function(value)
		local keySuccess, keyErr = keyChecker(value)
		if not keySuccess then
			return false, keyErr or ""
		end

		local valueSuccess, valueErr = valueChecker(value)
		if not valueSuccess then
			return false, valueErr or ""
		end

		return true
	end
end

do
	local arrayKeysCheck = t.keys(t.integer)
	--[[**
		ensures value is an array and all values of the array match check

		@param check The check to compare all values with

		@returns A function that will return true iff the condition is passed
	**--]]
	function t.array(check)
		assert(t.callback(check))
		local valuesCheck = t.values(check)

		return function(value)
			local keySuccess, keyErrMsg = arrayKeysCheck(value)
			if keySuccess == false then
				return false, string.format("[array] %s", keyErrMsg or "")
			end

			-- # is unreliable for sparse arrays
			-- Count upwards using ipairs to avoid false positives from the behavior of #
			local arraySize = 0

			for _ in ipairs(value) do
				arraySize = arraySize + 1
			end

			for key in pairs(value) do
				if key < 1 or key > arraySize then
					return false, string.format("[array] key %s must be sequential", tostring(key))
				end
			end

			local valueSuccess, valueErrMsg = valuesCheck(value)
			if not valueSuccess then
				return false, string.format("[array] %s", valueErrMsg or "")
			end

			return true
		end
	end
end

do
	local callbackArray = t.array(t.callback)
	--[[**
		creates a union type

		@param ... The checks to union

		@returns A function that will return true iff the condition is passed
	**--]]
	function t.union(...)
		local checks = {...}
		assert(callbackArray(checks))

		return function(value)
			for _, check in ipairs(checks) do
				if check(value) then
					return true
				end
			end

			return false, "bad type for union"
		end
	end

	--[[**
		Alias for t.union
	**--]]
	t.some = t.union

	--[[**
		creates an intersection type

		@param ... The checks to intersect

		@returns A function that will return true iff the condition is passed
	**--]]
	function t.intersection(...)
		local checks = {...}
		assert(callbackArray(checks))

		return function(value)
			for _, check in ipairs(checks) do
				local success, errMsg = check(value)
				if not success then
					return false, errMsg or ""
				end
			end

			return true
		end
	end

	--[[**
		Alias for t.intersection
	**--]]
	t.every = t.intersection
end

do
	local checkInterface = t.map(t.any, t.callback)
	--[[**
		ensures value matches given interface definition

		@param checkTable The interface definition

		@returns A function that will return true iff the condition is passed
	**--]]
	function t.interface(checkTable)
		assert(checkInterface(checkTable))
		return function(value)
			local tableSuccess, tableErrMsg = t.table(value)
			if tableSuccess == false then
				return false, tableErrMsg or ""
			end

			for key, check in pairs(checkTable) do
				local success, errMsg = check(value[key])
				if success == false then
					return false, string.format("[interface] bad value for %s:\n\t%s", tostring(key), errMsg or "")
				end
			end

			return true
		end
	end

	--[[**
		ensures value matches given interface definition strictly

		@param checkTable The interface definition

		@returns A function that will return true iff the condition is passed
	**--]]
	function t.strictInterface(checkTable)
		assert(checkInterface(checkTable))
		return function(value)
			local tableSuccess, tableErrMsg = t.table(value)
			if tableSuccess == false then
				return false, tableErrMsg or ""
			end

			for key, check in pairs(checkTable) do
				local success, errMsg = check(value[key])
				if success == false then
					return false, string.format("[interface] bad value for %s:\n\t%s", tostring(key), errMsg or "")
				end
			end

			for key in pairs(value) do
				if not checkTable[key] then
					return false, string.format("[interface] unexpected field %q", tostring(key))
				end
			end

			return true
		end
	end
end
