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--- Module for private utility functions
--- @param argc integer?
--- @return fun(...): any
local function concat_hash(argc)
return function(...)
return table.concat({ ... }, '%%', 1, argc)
end
end
--- @param idx integer
--- @return fun(...): any
local function idx_hash(idx)
return function(...)
return select(idx, ...)
end
end
--- @param hash integer|string|fun(...): any
--- @return fun(...): any
local function resolve_hash(hash)
if type(hash) == 'number' then
hash = idx_hash(hash)
elseif type(hash) == 'string' then
local c = hash == 'concat' or hash:match('^concat%-(%d+)')
if c then
hash = concat_hash(tonumber(c))
else
error('invalid value for hash: ' .. hash)
end
end
--- @cast hash -integer
return hash
end
--- @generic F: function
--- @param hash integer|string|fun(...): any
--- @param fn F
--- @param strong? boolean
--- @return F
return function(hash, fn, strong)
vim.validate('hash', hash, { 'number', 'string', 'function' })
vim.validate('fn', fn, 'function')
---@type table<any,table<any,any>>
local cache = {}
if not strong then
setmetatable(cache, { __mode = 'kv' })
end
hash = resolve_hash(hash)
return function(...)
local key = hash(...)
if cache[key] == nil then
cache[key] = vim.F.pack_len(fn(...))
end
return vim.F.unpack_len(cache[key])
end
end
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