真高兴啊。。。。实际的为开源事业做了点点贡献：），很久前指出的一个lua stdlib的bug得到确认
呵呵，是关于lua stdlib 库的set模块的bug，其实作者好像确认很久了。。。。但是我这段时间一直没有上gmail，所以没有看到。。。作者说，在新版中已经修改此bug…今天下了最新版，发现真是这样：）呵呵，真高兴啊，吸收了开源社区的那么多营养。。。总算有点报答了。。。当然，这仅仅是起步：）
实际流程贴一下。。。满足一下虚荣心。。。其实仅仅是一个很小的很容易发现的bug。。。呵呵，我当时学lua才一两周。。也不可能发现多么难的bug….lol
原来的lua stdlib set中某段程序如下：
-- @func propersubset: Find whether one set is a proper subset of another
-- @param s, t: sets
-- @returns
-- @param r: true if s is a proper subset of t, false otherwise
function propersubset (s, t)
return subset (s, t) and not subset (t, s)
end
-- @func equal: Find whether two sets are equal
-- @param s, t: sets
-- @returns
-- @param r: true if sets are equal, false otherwise
function equal (s, t)
return subset (s, t) and subset (s, t)
end
-- @head Metamethods for sets
-- set + table = union
metatable.__add = union
-- set - table = set difference
metatable.__sub = difference
-- set / table = intersection
metatable.__div = intersection
-- set <= table = subset
metatable.__le = subset
于是我发邮件给作者
hi all,
Thank you very much for your hard working with the LuaForWindows,I enjoy it so mush.
there is a bug to report as my return.
the set.lua file in the lualibs, 117th line.
source as this code:”return subset (s, t) and subset (s, t)”
it obviously should be “return subset (s,t) and subset(t, s)”
which means they are equal when s is the subset t and t is the subset s.
I hope I’m right and didn’t disturb you.
BTW,there is a surprising attribute.
In the set’s operations,div(/) mean intersection that is different from custom.
In the custom mul(*) denotes it,just like the «programming in Lua» writes in the 13th captial named “metatable and meatmethod”
Thank you for reading my poor Chinglish. lol,I’m Chinese.
Best wishes.
your honest
JTianLing from jtianling{at}gmail.com
luaforwindows的作者回信
Andrew Wilson to me, rrt, luaforwindows
show details Sep 3 Reply
Thanks for the bug report JTianLing, this particular module comes from
the stdlib library , I’ll copy your report of this issue to the
administrator of that project http://luaforge.net/projects/stdlib/
.
Your English is great, you wouldn’t want to even hear my Mandarin.
关心
Andrew Wilson
呵呵，不知道他这里说关心是什么意思……，惊奇的是。。。。他竟然还真能打中文字。。。。E文系统应该是没有中文输入法的吧。。。。
最后lua stdlib的作者回信：
Reuben Thomas to Andrew, me, luaforwindows
show details Sep 4 Reply
Thanks, this is quite correct. I’ve made a new release with this fix.
I see, I had actually forgotten that * is used in Modula-3 in the same way. I am happy to change this so that * is intersection and / is symmetric difference.
Thanks, I’ve made another release with these changes, and coincidentally fixed set.difference, which was also broken.
呵呵，最新版的set如下，可见已经修复，并且连那个我称为surprising attribute 的“/”符号表示交集也改了：）
-- @func intersection: Find the intersection of two sets
-- @param s, t: sets
-- @returns
-- @param r: set intersection of s and t
function intersection (s, t)
local r = new {}
for e in elements (s) do
if member (t, e) then
insert (r, e)
end
end
return r
end
-- @func union: Find the union of two sets
-- @param s, t: sets
-- @returns
-- @param r: set union of s and t
function union (s, t)
local r = new {}
for e in elements (s) do
insert (r, e)
end
for e in elements (t) do
insert (r, e)
end
return r
end
-- @func subset: Find whether one set is a subset of another
-- @param s, t: sets
-- @returns
-- @param r: true if s is a subset of t, false otherwise
function subset (s, t)
for e in elements (s) do
if not member (t, e) then
return false
end
end
return true
end
-- @func propersubset: Find whether one set is a proper subset of another
-- @param s, t: sets
-- @returns
-- @param r: true if s is a proper subset of t, false otherwise
function propersubset (s, t)
return subset (s, t) and not subset (t, s)
end
-- @func equal: Find whether two sets are equal
-- @param s, t: sets
-- @returns
-- @param r: true if sets are equal, false otherwise
function equal (s, t)
return subset (s, t) and subset (t, s)
end
-- @head Metamethods for sets
-- set + table = union
metatable.__add = union
-- set - table = set difference
metatable.__sub = difference
-- set * table = intersection
metatable.__mul = intersection
-- set / table = symmetric difference
metatable.__div = symmetric_difference
-- set <= table = subset
metatable.__le = subset
-- set < table = proper subset
metatable.__lt = propersubset
这虽然是一件芝麻一样的小事，但却是我个人第一次真正的为开源社区做贡献。。。。虽然仅仅是以bug report的形式：）立此存照：）
Posted By 九天雁翎 at 九天雁翎的博客 on 2008年10月27日