Re: [ANN] Lua 5.3.0 (work2) now available (number coercion holy crusade)
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- Subject: Re: [ANN] Lua 5.3.0 (work2) now available (number coercion holy crusade)
- From: William Ahern <william@...>
- Date: 2014年3月24日 18:43:35 -0700
On Mon, Mar 24, 2014 at 08:41:22PM -0400, Rena wrote:
> On Mar 24, 2014 6:34 PM, "Hisham" <[1]h@hisham.hm> wrote:
<snip>
> > who really likes a disciplined, typed world
<snip>
> I feel like format strings are one place where coercion is not a bad
> thing. It's all about making concise code that's easy to read and
> understand. When you write string.format("%d", x) it's clear that you
> intend x to represent a number, so having an implicit tonumber() around
> it makes sense. (Plus if x is, say, a table, an implicit conversion can
> throw an "expected number, got table" error,while if I'm remembering
> correctly tonumber(x) would return nil, making it harder to track down
> the bug.)
>
> In fact I don't see why such coercion is a bad thing in most cases,
> since context usually exists. You know that the operands to + must be
> numbers and .. must be strings.
>
All I know is that at work I always had to patch the Lua 5.1 VM to
implicitly call tostring on %s arguments.
I personally prefer stronger typing, but most of the engineers found the 5.1
behavior infuriating.
So I'm happy 5.2 and 5.3 invoke the tostring metamethod by default. I
imagine that I would receive similar complaints if the format specifier %d
didn't also coerce strings to numbers, especially considering that (%d+)
pattern matches return strings.