---
--- Lua Fun - a high-performance functional programming library for LuaJIT
---
--- Copyright (c) 2013-2017 Roman Tsisyk <roman@tsisyk.com>
---
--- Distributed under the MIT/X11 License. See COPYING.md for more details.
---
local exports = {}
local methods = {}
-- compatibility with Lua 5.1/5.2
local unpack = rawget(table, "unpack") or unpack
--------------------------------------------------------------------------------
-- Tools
--------------------------------------------------------------------------------
local return_if_not_empty = function(state_x, ...)
if state_x == nil then
return nil
end
return ...
end
local call_if_not_empty = function(fun, state_x, ...)
if state_x == nil then
return nil
end
return state_x, fun(...)
end
local function deepcopy(orig) -- used by cycle()
local orig_type = type(orig)
local copy
if orig_type == 'table' then
copy = {}
for orig_key, orig_value in next, orig, nil do
copy[deepcopy(orig_key)] = deepcopy(orig_value)
end
else
copy = orig
end
return copy
end
local iterator_mt = {
-- usually called by for-in loop
__call = function(self, param, state)
return self.gen(param, state)
end;
__tostring = function(self)
return '<generator>'
end;
-- add all exported methods
__index = methods;
}
local wrap = function(gen, param, state)
return setmetatable({
gen = gen,
param = param,
state = state
}, iterator_mt), param, state
end
exports.wrap = wrap
local unwrap = function(self)
return self.gen, self.param, self.state
end
methods.unwrap = unwrap
--------------------------------------------------------------------------------
-- Basic Functions
--------------------------------------------------------------------------------
local nil_gen = function(_param, _state)
return nil
end
local string_gen = function(param, state)
local state = state + 1
if state > #param then
return nil
end
local r = string.sub(param, state, state)
return state, r
end
local ipairs_gen = ipairs({}) -- get the generating function from ipairs
local pairs_gen = pairs({ a = 0 }) -- get the generating function from pairs
local map_gen = function(tab, key)
local value
local key, value = pairs_gen(tab, key)
return key, key, value
end
local rawiter = function(obj, param, state)
assert(obj ~= nil, "invalid iterator")
if type(obj) == "table" then
local mt = getmetatable(obj);
if mt ~= nil then
if mt == iterator_mt then
return obj.gen, obj.param, obj.state
elseif mt.__ipairs ~= nil then
return mt.__ipairs(obj)
elseif mt.__pairs ~= nil then
return mt.__pairs(obj)
end
end
if #obj > 0 then
-- array
return ipairs(obj)
else
-- hash
return map_gen, obj, nil
end
elseif (type(obj) == "function") then
return obj, param, state
elseif (type(obj) == "string") then
if #obj == 0 then
return nil_gen, nil, nil
end
return string_gen, obj, 0
end
error(string.format('object %s of type "%s" is not iterable',
obj, type(obj)))
end
local iter = function(obj, param, state)
return wrap(rawiter(obj, param, state))
end
exports.iter = iter
local method0 = function(fun)
return function(self)
return fun(self.gen, self.param, self.state)
end
end
local method1 = function(fun)
return function(self, arg1)
return fun(arg1, self.gen, self.param, self.state)
end
end
local method2 = function(fun)
return function(self, arg1, arg2)
return fun(arg1, arg2, self.gen, self.param, self.state)
end
end
local export0 = function(fun)
return function(gen, param, state)
return fun(rawiter(gen, param, state))
end
end
local export1 = function(fun)
return function(arg1, gen, param, state)
return fun(arg1, rawiter(gen, param, state))
end
end
local export2 = function(fun)
return function(arg1, arg2, gen, param, state)
return fun(arg1, arg2, rawiter(gen, param, state))
end
end
local each = function(fun, gen, param, state)
repeat
state = call_if_not_empty(fun, gen(param, state))
until state == nil
end
methods.each = method1(each)
exports.each = export1(each)
methods.for_each = methods.each
exports.for_each = exports.each
methods.foreach = methods.each
exports.foreach = exports.each
--------------------------------------------------------------------------------
-- Generators
--------------------------------------------------------------------------------
local range_gen = function(param, state)
local stop, step = param[1], param[2]
local state = state + step
if state > stop then
return nil
end
return state, state
end
local range_rev_gen = function(param, state)
local stop, step = param[1], param[2]
local state = state + step
if state < stop then
return nil
end
return state, state
end
local range = function(start, stop, step)
if step == nil then
if stop == nil then
if start == 0 then
return nil_gen, nil, nil
end
stop = start
start = stop > 0 and 1 or -1
end
step = start <= stop and 1 or -1
end
assert(type(start) == "number", "start must be a number")
assert(type(stop) == "number", "stop must be a number")
assert(type(step) == "number", "step must be a number")
assert(step ~= 0, "step must not be zero")
if (step > 0) then
return wrap(range_gen, {stop, step}, start - step)
elseif (step < 0) then
return wrap(range_rev_gen, {stop, step}, start - step)
end
end
exports.range = range
local duplicate_table_gen = function(param_x, state_x)
return state_x + 1, unpack(param_x)
end
local duplicate_fun_gen = function(param_x, state_x)
return state_x + 1, param_x(state_x)
end
local duplicate_gen = function(param_x, state_x)
return state_x + 1, param_x
end
local duplicate = function(...)
if select('#', ...) <= 1 then
return wrap(duplicate_gen, select(1, ...), 0)
else
return wrap(duplicate_table_gen, {...}, 0)
end
end
exports.duplicate = duplicate
exports.replicate = duplicate
exports.xrepeat = duplicate
local tabulate = function(fun)
assert(type(fun) == "function")
return wrap(duplicate_fun_gen, fun, 0)
end
exports.tabulate = tabulate
local zeros = function()
return wrap(duplicate_gen, 0, 0)
end
exports.zeros = zeros
local ones = function()
return wrap(duplicate_gen, 1, 0)
end
exports.ones = ones
local rands_gen = function(param_x, _state_x)
return 0, math.random(param_x[1], param_x[2])
end
local rands_nil_gen = function(_param_x, _state_x)
return 0, math.random()
end
local rands = function(n, m)
if n == nil and m == nil then
return wrap(rands_nil_gen, 0, 0)
end
assert(type(n) == "number", "invalid first arg to rands")
if m == nil then
m = n
n = 0
else
assert(type(m) == "number", "invalid second arg to rands")
end
assert(n < m, "empty interval")
return wrap(rands_gen, {n, m - 1}, 0)
end
exports.rands = rands
--------------------------------------------------------------------------------
-- Slicing
--------------------------------------------------------------------------------
local nth = function(n, gen_x, param_x, state_x)
assert(n > 0, "invalid first argument to nth")
-- An optimization for arrays and strings
if gen_x == ipairs_gen then
return param_x[n]
elseif gen_x == string_gen then
if n <= #param_x then
return string.sub(param_x, n, n)
else
return nil
end
end
for i=1,n-1,1 do
state_x = gen_x(param_x, state_x)
if state_x == nil then
return nil
end
end
return return_if_not_empty(gen_x(param_x, state_x))
end
methods.nth = method1(nth)
exports.nth = export1(nth)
local head_call = function(state, ...)
if state == nil then
error("head: iterator is empty")
end
return ...
end
local head = function(gen, param, state)
return head_call(gen(param, state))
end
methods.head = method0(head)
exports.head = export0(head)
exports.car = exports.head
methods.car = methods.head
local tail = function(gen, param, state)
state = gen(param, state)
if state == nil then
return wrap(nil_gen, nil, nil)
end
return wrap(gen, param, state)
end
methods.tail = method0(tail)
exports.tail = export0(tail)
exports.cdr = exports.tail
methods.cdr = methods.tail
local take_n_gen_x = function(i, state_x, ...)
if state_x == nil then
return nil
end
return {i, state_x}, ...
end
local take_n_gen = function(param, state)
local n, gen_x, param_x = param[1], param[2], param[3]
local i, state_x = state[1], state[2]
if i >= n then
return nil
end
return take_n_gen_x(i + 1, gen_x(param_x, state_x))
end
local take_n = function(n, gen, param, state)
assert(n >= 0, "invalid first argument to take_n")
return wrap(take_n_gen, {n, gen, param}, {0, state})
end
methods.take_n = method1(take_n)
exports.take_n = export1(take_n)
local take_while_gen_x = function(fun, state_x, ...)
if state_x == nil or not fun(...) then
return nil
end
return state_x, ...
end
local take_while_gen = function(param, state_x)
local fun, gen_x, param_x = param[1], param[2], param[3]
return take_while_gen_x(fun, gen_x(param_x, state_x))
end
local take_while = function(fun, gen, param, state)
assert(type(fun) == "function", "invalid first argument to take_while")
return wrap(take_while_gen, {fun, gen, param}, state)
end
methods.take_while = method1(take_while)
exports.take_while = export1(take_while)
local take = function(n_or_fun, gen, param, state)
if type(n_or_fun) == "number" then
return take_n(n_or_fun, gen, param, state)
else
return take_while(n_or_fun, gen, param, state)
end
end
methods.take = method1(take)
exports.take = export1(take)
local drop_n = function(n, gen, param, state)
assert(n >= 0, "invalid first argument to drop_n")
local i
for i=1,n,1 do
state = gen(param, state)
if state == nil then
return wrap(nil_gen, nil, nil)
end
end
return wrap(gen, param, state)
end
methods.drop_n = method1(drop_n)
exports.drop_n = export1(drop_n)
local drop_while_x = function(fun, state_x, ...)
if state_x == nil or not fun(...) then
return state_x, false
end
return state_x, true, ...
end
local drop_while = function(fun, gen_x, param_x, state_x)
assert(type(fun) == "function", "invalid first argument to drop_while")
local cont, state_x_prev
repeat
state_x_prev = deepcopy(state_x)
state_x, cont = drop_while_x(fun, gen_x(param_x, state_x))
until not cont
if state_x == nil then
return wrap(nil_gen, nil, nil)
end
return wrap(gen_x, param_x, state_x_prev)
end
methods.drop_while = method1(drop_while)
exports.drop_while = export1(drop_while)
local drop = function(n_or_fun, gen_x, param_x, state_x)
if type(n_or_fun) == "number" then
return drop_n(n_or_fun, gen_x, param_x, state_x)
else
return drop_while(n_or_fun, gen_x, param_x, state_x)
end
end
methods.drop = method1(drop)
exports.drop = export1(drop)
local split = function(n_or_fun, gen_x, param_x, state_x)
return take(n_or_fun, gen_x, param_x, state_x),
drop(n_or_fun, gen_x, param_x, state_x)
end
methods.split = method1(split)
exports.split = export1(split)
methods.split_at = methods.split
exports.split_at = exports.split
methods.span = methods.split
exports.span = exports.split
--------------------------------------------------------------------------------
-- Indexing
--------------------------------------------------------------------------------
local index = function(x, gen, param, state)
local i = 1
for _k, r in gen, param, state do
if r == x then
return i
end
i = i + 1
end
return nil
end
methods.index = method1(index)
exports.index = export1(index)
methods.index_of = methods.index
exports.index_of = exports.index
methods.elem_index = methods.index
exports.elem_index = exports.index
local indexes_gen = function(param, state)
local x, gen_x, param_x = param[1], param[2], param[3]
local i, state_x = state[1], state[2]
local r
while true do
state_x, r = gen_x(param_x, state_x)
if state_x == nil then
return nil
end
i = i + 1
if r == x then
return {i, state_x}, i
end
end
end
local indexes = function(x, gen, param, state)
return wrap(indexes_gen, {x, gen, param}, {0, state})
end
methods.indexes = method1(indexes)
exports.indexes = export1(indexes)
methods.elem_indexes = methods.indexes
exports.elem_indexes = exports.indexes
methods.indices = methods.indexes
exports.indices = exports.indexes
methods.elem_indices = methods.indexes
exports.elem_indices = exports.indexes
--------------------------------------------------------------------------------
-- Filtering
--------------------------------------------------------------------------------
local filter1_gen = function(fun, gen_x, param_x, state_x, a)
while true do
if state_x == nil or fun(a) then break; end
state_x, a = gen_x(param_x, state_x)
end
return state_x, a
end
-- call each other
local filterm_gen
local filterm_gen_shrink = function(fun, gen_x, param_x, state_x)
return filterm_gen(fun, gen_x, param_x, gen_x(param_x, state_x))
end
filterm_gen = function(fun, gen_x, param_x, state_x, ...)
if state_x == nil then
return nil
end
if fun(...) then
return state_x, ...
end
return filterm_gen_shrink(fun, gen_x, param_x, state_x)
end
local filter_detect = function(fun, gen_x, param_x, state_x, ...)
if select('#', ...) < 2 then
return filter1_gen(fun, gen_x, param_x, state_x, ...)
else
return filterm_gen(fun, gen_x, param_x, state_x, ...)
end
end
local filter_gen = function(param, state_x)
local fun, gen_x, param_x = param[1], param[2], param[3]
return filter_detect(fun, gen_x, param_x, gen_x(param_x, state_x))
end
local filter = function(fun, gen, param, state)
return wrap(filter_gen, {fun, gen, param}, state)
end
methods.filter = method1(filter)
exports.filter = export1(filter)
methods.remove_if = methods.filter
exports.remove_if = exports.filter
local grep = function(fun_or_regexp, gen, param, state)
local fun = fun_or_regexp
if type(fun_or_regexp) == "string" then
fun = function(x) return string.find(x, fun_or_regexp) ~= nil end
end
return filter(fun, gen, param, state)
end
methods.grep = method1(grep)
exports.grep = export1(grep)
local partition = function(fun, gen, param, state)
local neg_fun = function(...)
return not fun(...)
end
return filter(fun, gen, param, state),
filter(neg_fun, gen, param, state)
end
methods.partition = method1(partition)
exports.partition = export1(partition)
--------------------------------------------------------------------------------
-- Reducing
--------------------------------------------------------------------------------
local foldl_call = function(fun, start, state, ...)
if state == nil then
return nil, start
end
return state, fun(start, ...)
end
local foldl = function(fun, start, gen_x, param_x, state_x)
while true do
state_x, start = foldl_call(fun, start, gen_x(param_x, state_x))
if state_x == nil then
break;
end
end
return start
end
methods.foldl = method2(foldl)
exports.foldl = export2(foldl)
methods.reduce = methods.foldl
exports.reduce = exports.foldl
local length = function(gen, param, state)
if gen == ipairs_gen or gen == string_gen then
return #param
end
local len = 0
repeat
state = gen(param, state)
len = len + 1
until state == nil
return len - 1
end
methods.length = method0(length)
exports.length = export0(length)
local is_null = function(gen, param, state)
return gen(param, deepcopy(state)) == nil
end
methods.is_null = method0(is_null)
exports.is_null = export0(is_null)
local is_prefix_of = function(iter_x, iter_y)
local gen_x, param_x, state_x = iter(iter_x)
local gen_y, param_y, state_y = iter(iter_y)
local r_x, r_y
for i=1,10,1 do
state_x, r_x = gen_x(param_x, state_x)
state_y, r_y = gen_y(param_y, state_y)
if state_x == nil then
return true
end
if state_y == nil or r_x ~= r_y then
return false
end
end
end
methods.is_prefix_of = is_prefix_of
exports.is_prefix_of = is_prefix_of
local all = function(fun, gen_x, param_x, state_x)
local r
repeat
state_x, r = call_if_not_empty(fun, gen_x(param_x, state_x))
until state_x == nil or not r
return state_x == nil
end
methods.all = method1(all)
exports.all = export1(all)
methods.every = methods.all
exports.every = exports.all
local any = function(fun, gen_x, param_x, state_x)
local r
repeat
state_x, r = call_if_not_empty(fun, gen_x(param_x, state_x))
until state_x == nil or r
return not not r
end
methods.any = method1(any)
exports.any = export1(any)
methods.some = methods.any
exports.some = exports.any
local sum = function(gen, param, state)
local s = 0
local r = 0
repeat
s = s + r
state, r = gen(param, state)
until state == nil
return s
end
methods.sum = method0(sum)
exports.sum = export0(sum)
local product = function(gen, param, state)
local p = 1
local r = 1
repeat
p = p * r
state, r = gen(param, state)
until state == nil
return p
end
methods.product = method0(product)
exports.product = export0(product)
local min_cmp = function(m, n)
if n < m then return n else return m end
end
local max_cmp = function(m, n)
if n > m then return n else return m end
end
local min = function(gen, param, state)
local state, m = gen(param, state)
if state == nil then
error("min: iterator is empty")
end
local cmp
if type(m) == "number" then
-- An optimization: use math.min for numbers
cmp = math.min
else
cmp = min_cmp
end
for _, r in gen, param, state do
m = cmp(m, r)
end
return m
end
methods.min = method0(min)
exports.min = export0(min)
methods.minimum = methods.min
exports.minimum = exports.min
local min_by = function(cmp, gen_x, param_x, state_x)
local state_x, m = gen_x(param_x, state_x)
if state_x == nil then
error("min: iterator is empty")
end
for _, r in gen_x, param_x, state_x do
m = cmp(m, r)
end
return m
end
methods.min_by = method1(min_by)
exports.min_by = export1(min_by)
methods.minimum_by = methods.min_by
exports.minimum_by = exports.min_by
local max = function(gen_x, param_x, state_x)
local state_x, m = gen_x(param_x, state_x)
if state_x == nil then
error("max: iterator is empty")
end
local cmp
if type(m) == "number" then
-- An optimization: use math.max for numbers
cmp = math.max
else
cmp = max_cmp
end
for _, r in gen_x, param_x, state_x do
m = cmp(m, r)
end
return m
end
methods.max = method0(max)
exports.max = export0(max)
methods.maximum = methods.max
exports.maximum = exports.max
local max_by = function(cmp, gen_x, param_x, state_x)
local state_x, m = gen_x(param_x, state_x)
if state_x == nil then
error("max: iterator is empty")
end
for _, r in gen_x, param_x, state_x do
m = cmp(m, r)
end
return m
end
methods.max_by = method1(max_by)
exports.max_by = export1(max_by)
methods.maximum_by = methods.maximum_by
exports.maximum_by = exports.maximum_by
local totable = function(gen_x, param_x, state_x)
local tab, key, val = {}
while true do
state_x, val = gen_x(param_x, state_x)
if state_x == nil then
break
end
table.insert(tab, val)
end
return tab
end
methods.totable = method0(totable)
exports.totable = export0(totable)
local tomap = function(gen_x, param_x, state_x)
local tab, key, val = {}
while true do
state_x, key, val = gen_x(param_x, state_x)
if state_x == nil then
break
end
tab[key] = val
end
return tab
end
methods.tomap = method0(tomap)
exports.tomap = export0(tomap)
--------------------------------------------------------------------------------
-- Transformations
--------------------------------------------------------------------------------
local map_gen = function(param, state)
local gen_x, param_x, fun = param[1], param[2], param[3]
return call_if_not_empty(fun, gen_x(param_x, state))
end
local map = function(fun, gen, param, state)
return wrap(map_gen, {gen, param, fun}, state)
end
methods.map = method1(map)
exports.map = export1(map)
local enumerate_gen_call = function(state, i, state_x, ...)
if state_x == nil then
return nil
end
return {i + 1, state_x}, i, ...
end
local enumerate_gen = function(param, state)
local gen_x, param_x = param[1], param[2]
local i, state_x = state[1], state[2]
return enumerate_gen_call(state, i, gen_x(param_x, state_x))
end
local enumerate = function(gen, param, state)
return wrap(enumerate_gen, {gen, param}, {1, state})
end
methods.enumerate = method0(enumerate)
exports.enumerate = export0(enumerate)
local intersperse_call = function(i, state_x, ...)
if state_x == nil then
return nil
end
return {i + 1, state_x}, ...
end
local intersperse_gen = function(param, state)
local x, gen_x, param_x = param[1], param[2], param[3]
local i, state_x = state[1], state[2]
if i % 2 == 1 then
return {i + 1, state_x}, x
else
return intersperse_call(i, gen_x(param_x, state_x))
end
end
-- TODO: interperse must not add x to the tail
local intersperse = function(x, gen, param, state)
return wrap(intersperse_gen, {x, gen, param}, {0, state})
end
methods.intersperse = method1(intersperse)
exports.intersperse = export1(intersperse)
--------------------------------------------------------------------------------
-- Compositions
--------------------------------------------------------------------------------
local function zip_gen_r(param, state, state_new, ...)
if #state_new == #param / 2 then
return state_new, ...
end
local i = #state_new + 1
local gen_x, param_x = param[2 * i - 1], param[2 * i]
local state_x, r = gen_x(param_x, state[i])
if state_x == nil then
return nil
end
table.insert(state_new, state_x)
return zip_gen_r(param, state, state_new, r, ...)
end
local zip_gen = function(param, state)
return zip_gen_r(param, state, {})
end
-- A special hack for zip/chain to skip last two state, if a wrapped iterator
-- has been passed
local numargs = function(...)
local n = select('#', ...)
if n >= 3 then
-- Fix last argument
local it = select(n - 2, ...)
if type(it) == 'table' and getmetatable(it) == iterator_mt and
it.param == select(n - 1, ...) and it.state == select(n, ...) then
return n - 2
end
end
return n
end
local zip = function(...)
local n = numargs(...)
if n == 0 then
return wrap(nil_gen, nil, nil)
end
local param = { [2 * n] = 0 }
local state = { [n] = 0 }
local i, gen_x, param_x, state_x
for i=1,n,1 do
local it = select(n - i + 1, ...)
gen_x, param_x, state_x = rawiter(it)
param[2 * i - 1] = gen_x
param[2 * i] = param_x
state[i] = state_x
end
return wrap(zip_gen, param, state)
end
methods.zip = zip
exports.zip = zip
local cycle_gen_call = function(param, state_x, ...)
if state_x == nil then
local gen_x, param_x, state_x0 = param[1], param[2], param[3]
return gen_x(param_x, deepcopy(state_x0))
end
return state_x, ...
end
local cycle_gen = function(param, state_x)
local gen_x, param_x, state_x0 = param[1], param[2], param[3]
return cycle_gen_call(param, gen_x(param_x, state_x))
end
local cycle = function(gen, param, state)
return wrap(cycle_gen, {gen, param, state}, deepcopy(state))
end
methods.cycle = method0(cycle)
exports.cycle = export0(cycle)
-- call each other
local chain_gen_r1
local chain_gen_r2 = function(param, state, state_x, ...)
if state_x == nil then
local i = state[1]
i = i + 1
if param[3 * i - 1] == nil then
return nil
end
local state_x = param[3 * i]
return chain_gen_r1(param, {i, state_x})
end
return {state[1], state_x}, ...
end
chain_gen_r1 = function(param, state)
local i, state_x = state[1], state[2]
local gen_x, param_x = param[3 * i - 2], param[3 * i - 1]
return chain_gen_r2(param, state, gen_x(param_x, state[2]))
end
local chain = function(...)
local n = numargs(...)
if n == 0 then
return wrap(nil_gen, nil, nil)
end
local param = { [3 * n] = 0 }
local i, gen_x, param_x, state_x
for i=1,n,1 do
local elem = select(i, ...)
gen_x, param_x, state_x = iter(elem)
param[3 * i - 2] = gen_x
param[3 * i - 1] = param_x
param[3 * i] = state_x
end
return wrap(chain_gen_r1, param, {1, param[3]})
end
methods.chain = chain
exports.chain = chain
--------------------------------------------------------------------------------
-- Operators
--------------------------------------------------------------------------------
local operator = {
----------------------------------------------------------------------------
-- Comparison operators
----------------------------------------------------------------------------
lt = function(a, b) return a < b end,
le = function(a, b) return a <= b end,
eq = function(a, b) return a == b end,
ne = function(a, b) return a ~= b end,
ge = function(a, b) return a >= b end,
gt = function(a, b) return a > b end,
----------------------------------------------------------------------------
-- Arithmetic operators
----------------------------------------------------------------------------
add = function(a, b) return a + b end,
div = function(a, b) return a / b end,
floordiv = function(a, b) return math.floor(a/b) end,
intdiv = function(a, b)
local q = a / b
if a >= 0 then return math.floor(q) else return math.ceil(q) end
end,
mod = function(a, b) return a % b end,
mul = function(a, b) return a * b end,
neq = function(a) return -a end,
unm = function(a) return -a end, -- an alias
pow = function(a, b) return a ^ b end,
sub = function(a, b) return a - b end,
truediv = function(a, b) return a / b end,
----------------------------------------------------------------------------
-- String operators
----------------------------------------------------------------------------
concat = function(a, b) return a..b end,
len = function(a) return #a end,
length = function(a) return #a end, -- an alias
----------------------------------------------------------------------------
-- Logical operators
----------------------------------------------------------------------------
land = function(a, b) return a and b end,
lor = function(a, b) return a or b end,
lnot = function(a) return not a end,
truth = function(a) return not not a end,
}
exports.operator = operator
methods.operator = operator
exports.op = operator
methods.op = operator
--------------------------------------------------------------------------------
-- module definitions
--------------------------------------------------------------------------------
-- a special syntax sugar to export all functions to the global table
setmetatable(exports, {
__call = function(t, override)
for k, v in pairs(t) do
if rawget(_G, k) ~= nil then
local msg = 'function ' .. k .. ' already exists in global scope.'
if override then
rawset(_G, k, v)
print('WARNING: ' .. msg .. ' Overwritten.')
else
print('NOTICE: ' .. msg .. ' Skipped.')
end
else
rawset(_G, k, v)
end
end
end,
})
return exports
