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- Subject: Re: Command line library load in Lua 5.2
- From: Dirk Laurie <dirk.laurie@...>
- Date: Thu, 3 Nov 2011 15:56:25 +0200
2011/11/3 Matthew Wild <email@example.com>:
> I'm confused... if you're going to use require(), that also sets
> package.loaded if not already set. So... how is -l useful if you have
> to call require right after anyway?
Don't think of '-l' as being merely convenient. Think of it as
providing command-line control over loading of modules.
For example: the program has:
mod1 = require "mod1"
mod2 = require "mod2"
mod3 = require "mod3"
mod12 = require "mod12"
These modules are supposed to be independent of each other, but the
program has an obscure bug. You suspect that one of these modules is
setting a global which affects one of the others. Without any need to
edit the source (which may have been supplied to you as bytecode) you
can do this:
$ lua -l mod4 prog.lua
Now "mod4" gets loaded first.
And this sort of application is why I'm pushing for extending the
syntax of '-l' to allow
$ lua -l mod4=mod4_patched prog.lua
That would allow '-l' to achieve command-line templating.