Module:UtilsFunction: Difference between revisions
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function p.identity(...) | function p.identity(...) | ||
return ... | return ... | ||
end | |||
function p.memoize(fn) | |||
local cache = {} | |||
return function(...) | |||
local key = mw.dumpObject({...}) | |||
if not cache[key] then | |||
cache[key] = fn(...) | |||
end | |||
return cache[key] | |||
end | |||
end | end | ||
Revision as of 17:12, 3 May 2020
The functions in this module return other functions, namely iterators. It also contains utility functions for functional programming.
local p = {}
function p.identity(...)
return ...
end
function p.memoize(fn)
local cache = {}
return function(...)
local key = mw.dumpObject({...})
if not cache[key] then
cache[key] = fn(...)
end
return cache[key]
end
end
function p.negate(fn)
return function(...)
return not fn(...)
end
end
function p.noop()
return nil
end
function p.peek(tbl)
mw.logObject(tbl)
return tbl
end
function p.pipe(...)
local state = {...}
return function(functions)
for _, fn in ipairs(functions) do
state = {fn(unpack(state))}
end
return unpack(state)
end
end
-- http://lua-users.org/wiki/RangeIterator
function p.range(a, b, step)
if not b then
b = a
a = 1
end
step = step or 1
local f =
step > 0 and
function(_, lastvalue)
local nextvalue = lastvalue + step
if nextvalue <= b then return nextvalue end
end or
step < 0 and
function(_, lastvalue)
local nextvalue = lastvalue + step
if nextvalue >= b then return nextvalue end
end or
function(_, lastvalue) return lastvalue end
return f, nil, a - step
end
return p