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Brace expansion: Difference between revisions
Added Lua.
Thundergnat (talk | contribs) m (→{{header|C sharp}}: Regularize header markup to recommended on category page) |
(Added Lua.) |
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{}} some }{,{\\ edge \,}{ cases, {here} \\\\\}
{}} some }{,{\\ edge \,}{ cases, {here} \\\\\}
</pre>
=={{header|Lua}}==
{{trans|Python}}
Note that this code isn't very memory efficient.
<lang Lua>local function wrapEachItem(items, prefix, suffix)
local itemsWrapped = {}
for i, item in ipairs(items) do
itemsWrapped[i] = prefix .. item .. suffix
end
return itemsWrapped
end
local function getAllItemCombinationsConcatenated(aItems, bItems)
local combinations = {}
for _, a in ipairs(aItems) do
for _, b in ipairs(bItems) do
table.insert(combinations, a..b)
end
end
return combinations
end
local getItems -- Forward declaration.
local function getGroup(s, pos, depth)
local groupItems = {}
local foundComma = false
while pos <= #s do
local items
items, pos = getItems(s, pos, depth)
if pos > #s then break end
for _, item in ipairs(items) do
table.insert(groupItems, item)
end
local c = s:sub(pos, pos)
if c == "}" then -- Possibly end of group.
if foundComma then return groupItems, pos+1 end
return wrapEachItem(groupItems, "{", "}"), pos+1 -- No group.
elseif c == "," then
foundComma, pos = true, pos+1
end
end
return nil -- No group.
end
function getItems(s, pos, depth)
local items = {""}
while pos <= #s do
local c = s:sub(pos, pos)
if depth > 0 and (c == "," or c == "}") then -- End of item in surrounding group.
return items, pos
end
local groupItems, nextPos = nil
if c == "{" then -- Possibly start of a group.
groupItems, nextPos = getGroup(s, pos+1, depth+1)
end
if groupItems then
items, pos = getAllItemCombinationsConcatenated(items, groupItems), nextPos
else
if c == "\\" and pos < #s then -- Escaped character.
pos = pos + 1
c = c .. s:sub(pos, pos)
end
items, pos = wrapEachItem(items, "", c), pos+1
end
end
return items, pos
end
local tests = [[
~/{Downloads,Pictures}/*.{jpg,gif,png}
It{{em,alic}iz,erat}e{d,}, please.
{,{,gotta have{ ,\, again\, }}more }cowbell!
{}} some }{,{\\{ edge, edge} \,}{ cases, {here} \\\\\}
]]
for test in tests:gmatch"[^\n]+" do
print(test)
for _, item in ipairs(getItems(test, 1, 0)) do
print("\t"..item)
end
print()
end</lang>
{{out}}
<pre>
~/{Downloads,Pictures}/*.{jpg,gif,png}
~/Downloads/*.jpg
~/Downloads/*.gif
~/Downloads/*.png
~/Pictures/*.jpg
~/Pictures/*.gif
~/Pictures/*.png
...
{}} some }{,{\\{ edge, edge} \,}{ cases, {here} \\\\\}
{}} some }{,{\\ edge \,}{ cases, {here} \\\\\}
{}} some }{,{\\ edge \,}{ cases, {here} \\\\\}
</pre>
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