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added tablex.copy is an alias for tablex.shallow_copy, same for overlay, bunch of whitespace changes, some additional asserts

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This commit is contained in:
Max Cahill 2022-03-07 12:00:05 +11:00
parent de5c803389
commit 213ba5df0f
1 changed files with 29 additions and 15 deletions
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32
tablex.lua
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@ -331,6 +331,7 @@ end
-- Copy a table
-- See shallow_overlay to shallow copy into an existing table to avoid garbage.
function tablex.shallow_copy(t)
assert:type(t, "table", "tablex.shallow_copy - t", 1)
if type(t) == "table" then
local into = {}
for k, v in pairs(t) do
@ -341,29 +342,39 @@ function tablex.shallow_copy(t)
return t
end
local function deep_copy(t, copied)
--alias
tablex.copy = tablex.shallow_copy
--implementation for deep copy
--traces stuff that has already been copied, to handle circular references
local function _deep_copy_impl(t, already_copied)
local clone = t
if type(t) == "table" then
if copied[t] then
clone = copied[t]
if already_copied[t] then
--something we've already encountered before
clone = already_copied[t]
elseif type(t.copy) == "function" then
--something that provides its own copy function
clone = t:copy()
assert:type(clone, "table", "copy() didn't return a copy")
assert:type(clone, "table", "member copy() function didn't return a copy")
else
--a plain table to clone
clone = {}
for k, v in pairs(t) do
clone[k] = deep_copy(v, copied)
clone[k] = _deep_copy_impl(v, already_copied)
end
setmetatable(clone, getmetatable(t))
copied[t] = clone
already_copied[t] = clone
end
end
return clone
end
-- Recursively copy values of a table.
-- Retains the same keys as original table -- they're not cloned.
function tablex.deep_copy(t)
return deep_copy(t, {})
assert:type(t, "table", "tablex.deep_copy - t", 1)
return _deep_copy_impl(t, {})
end
-- Overlay tables directly onto one another, merging them together.
@ -383,6 +394,8 @@ function tablex.shallow_overlay(dest, ...)
return dest
end
tablex.overlay = tablex.shallow_overlay
-- Overlay tables directly onto one another, merging them together into something like a union.
-- Also overlays nested tables, but doesn't clone them (so a nested table may be added to dest).
-- Takes as many tables as required,
@ -437,6 +450,7 @@ function tablex.shallow_equal(a, b)
end
end
-- second loop to ensure a isn't missing any keys from b.
-- we don't compare the values - if any are missing we're not equal
for k, v in pairs(b) do
if a[k] == nil then
return false
@ -462,8 +476,8 @@ function tablex.deep_equal(a, b)
return false
end
end
-- second loop to ensure a isn't missing any keys from b, so we can skip
-- recursion.
-- second loop to ensure a isn't missing any keys from b
-- we don't compare the values - if any are missing we're not equal
for k, v in pairs(b) do
if a[k] == nil then
return false