你如何用lua构建一个读写管道? [英] How do you construct a read-write pipe with lua?

问题描述

我想做相当于:

foo=$(echo "$foo"|someprogram)

在 lua 中——即，我有一个包含一堆文本的变量，我想通过过滤器(在 python 中实现)来运行它.

within lua -- ie, I've got a variable containing a bunch of text, and I'd like to run it through a filter (implemented in python as it happens).

有什么提示吗?

补充:真的很想在不使用临时文件的情况下做到这一点

Added: would really like to do this without using a temporary file

推荐答案

啊哈，一个可能更好的解决方案:

Aha, a possibly better solution:

require('posix')
require('os')
require('io')

function splat_popen(data,cmd)
   rd,wr = posix.pipe()
   io.flush()
   child = posix.fork()
   if child == 0 then
      rd:close()
      wr:write(data)
      io.flush()
      os.exit(1)
   end
   wr:close()

   rd2,wr2 = posix.pipe()
   io.flush()
   child2 = posix.fork()
   if child2 == 0 then
      rd2:close()
      posix.dup(rd,io.stdin)
      posix.dup(wr2,io.stdout)
      posix.exec(cmd)
      os.exit(2)
   end
   wr2:close()
   rd:close()

   y = rd2:read("*a")
   rd2:close()

   posix.wait(child2)
   posix.wait(child)

   return y
end

munged=splat_popen("hello, world","/usr/games/rot13")
print("munged: "..munged.." !")

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