Re: Questions about string.pack() and string.unpack()

[Coda Highland <chighland@...>]

On Wed, Nov 19, 2014 at 5:06 PM, Sean Conner <sean@conman.org> wrote:
>
>   I'm looking over string.pack() and string.unpack() in Lua 5.3, and I have
> a few questions:
>
> 1.  Why is string.unpack(fmt,s[,pos]) instead of string.unpack(s,fmt[,pos])?
>     This means I can't do:
>
>                 magic,timestamp,tag = raw:unpack("I4I4I4")
>
>     Instead, it's:
>
>                 magic,timestamp,tag = string.unpack("I4I4I4",raw)
>
>     This also means I may have to cache the string table in a local variable
>     in a module when it might be avoided.   The former also "reads" better
>     to me.

The rationale is because most functions (e.g. printf) take their
format strings as the first parameter.

Why not ("l4l4l4"):unpack(raw)? That avoids the caching the string table.

/s/ Adam