Re: string.gsub accepting a callable userdata
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- Subject: Re: string.gsub accepting a callable userdata
- From: Jerome Vuarand <jerome.vuarand@...>
- Date: 2012年12月13日 18:02:45 +0000
2012年12月13日 steve donovan <steve.j.donovan@gmail.com>:
> That does work - gsub respects __index, which is nice (I had to check this)
>
> Best global solution in such a situation is the following monkey patch:
>
> local gsub,type = string.gsub,type
>
> function string.gsub(s,pat,repl)
> if type(repl) == 'userdata' then
> local obj = repl
> repl = function(...) return obj(...) end
> end
> return gsub(s,pat,repl)
> end
To avoid the creation of a closure on each call, you can cache one:
local gsub,type = string.gsub,type
local ref = setmetatable({}, {__weak='v'})
local function unref(...) return ref[1](...) end
function string.gsub(s,pat,repl)
if type(repl) == 'userdata' then
ref[1] = repl
repl = unref
end
return gsub(s,pat,repl)
end