Re: string.gsub accepting a callable userdata

[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index] [Thread Index]

• Subject: Re: string.gsub accepting a callable userdata
• From: David Favro <lua@...>
• Date: 2012年12月13日 14:14:32 -0500

---

On 12/13/2012 01:02 PM, Jerome Vuarand wrote:

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

Wouldn't this be non-reentrant should the called userdata itself call gsub() [or cause it to be called via loaded script]? ref[1] would now be the inner gsub()'s repl, and when the outer gsub() finds another match it will call unref() again which will dereference to the wrong repl.

---

• Follow-Ups:
  • Re: string.gsub accepting a callable userdata, Jerome Vuarand

• References:
  • string.gsub accepting a callable userdata, steve donovan
  • Re: string.gsub accepting a callable userdata, Wesley Smith
  • Re: string.gsub accepting a callable userdata, steve donovan
  • Re: string.gsub accepting a callable userdata, Jerome Vuarand

• Prev by Date: Re: string.gsub accepting a callable userdata
• Next by Date: Re: string.gsub accepting a callable userdata
• Previous by thread: Re: string.gsub accepting a callable userdata
• Next by thread: Re: string.gsub accepting a callable userdata
• Index(es):
  • Date
  • Thread