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See setfenv() in the lua docs

http://www.lua.org/manual/5.0/manual.html#5.1

> -----Original Message-----
> From: lua-bounces@bazar2.conectiva.com.br 
> [mailto:lua-bounces@bazar2.conectiva.com.br] On Behalf Of 
> Peter Hickman
> Sent: Monday, March 29, 2004 12:50 PM
> To: Lua list
> Subject: Controlling scoping
> 
> 
> I have a little project where I turn pages like...
> 
> [Lua]$ cat test1.html
> <html>
>         <head>
>                 <title>This is a test Lua page</title>
>         </head>
>         <body>
>                 <p>Todays date is [% io.write(os.date("%Y/%m/%d 
> %H:%M:%S")) %]</p>
>                 <p>We can also calculate 1 + 1 = [% io.write(
> 1
> +
> 1
> )%]</p>
>                 <p>And now a list:</p>
>                 <ol>
> [%  a = {'tom', 'dick', 'harry'}
>         for i,v in ipairs(a) do %]
>                         <li>[% io.write(v) %]</li>
> [%  end%]
>                 </ol>
>                 <p>[% x = 42 %]Here we set x to [% io.write(x) %]</p>
>         </body>
> </html>
> [Lua]$
> 
> into functions...
> io.write("<html>\n      <head>\n                <title>This is a test 
> Lua page</title>\n        </head>\n       <body>\n           
> <p>Todays 
> date is ")
> io.write(os.date("%Y/%m/%d %H:%M:%S"))
> io.write("</p>\n                <p>We can also calculate 1 + 1 = ")
> io.write( 1 + 1 )
> io.write("</p>\n                <p>And now a list:</p>\n      
>           
> <ol>\n")
> a = {'tom', 'dick', 'harry'}  for i,v in ipairs(a) do
>   io.write("                      <li>")
>   io.write(v)
>   io.write("</li> \n")
> end
> io.write("              </ol>\n         <p>")
> x = 42
> io.write("Here we set x to ")
> io.write(x)
> io.write("</p>\n        </body>\n</html>\n")
> 
> Which when called will render the page...
> <html>
>         <head>
>                 <title>This is a test Lua page</title>
>         </head>
>         <body>
>                 <p>Todays date is 2004/03/29 21:44:37</p>
>                 <p>We can also calculate 1 + 1 = 2</p>
>                 <p>And now a list:</p>
>                 <ol>
>                         <li>tom</li>
>                         <li>dick</li>
>                         <li>harry</li>
>                 </ol>
>                 <p>Here we set x to 42</p>
>         </body>
> </html>
> 
> I can store the function in a table and call whenever I need 
> to display 
> the page. A bit like JSP or Mason.
> 
> The problem that I have is shown in the following example 
> which strips 
> things down...
> [Lua]$ cat example.lua
> #!/usr/local/bin/lua
> 
> s1 = "x = 42"
> s2 = "print(x)"
> 
> c1 = loadstring(s1)
> c2 = loadstring(s2)
> 
> c2()
> c1()
> c2()
> [Lua]$
> 
> When I run this I get
> nil
> 42
> as the output. But what I really want is
> nil
> nil
> 
> I want the scope of c1 to be independent of c2. Now in the example I 
> could use
> s1 = "local x = 42"
> but in the LSP's (Lua Server Pages perhaps) I don't want the 
> programmer 
> to have to explicitly scope all their variables as local 
> because 1, its 
> a real pain and 2, some are going to slip through and make for a very 
> difficult bug. Any ideas how I might wrap the compiled 
> functions (c1 and 
> c2) up so that all the variables they use are local to the functions?
>