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Ok, failing on nil may be useful.

But booleans?

I see this mostly been done in debug messages.
I think I'll roll my own special debug formatting in C which
concats all args and tostrings what isn't string already.

Thanks.

On 08/25/2014 08:30 AM, Dirk Laurie wrote:

The pressing question for most of us is productivity rather than
processing time. Consider the following situation: somewhere
in my program, I have the statement

    full_name = first_name .. " " .. surname

Nobody reading the program is going to think there is
a mistake.

Unfortunately, some distance earlier, I gave a value to "firstname",
not "first_name". At present, at this very statement, Lua
throws an error because first_name is nil, I find the mistake
immediately and correct it.

How would it be if the first time I notice this mistake is when
annoyed clients ring up one after the other to tell me their names
are not "nil Zoller" etc?



2014-08-25 7:51 GMT+02:00 Dirk Zoller <duz@sol-3.de>:

Hi All,

Looking at Lua-Reference for 5.2 section 3.4.2.
Coercion happens to numbers when used where a string is expected.
It is done the same way as tostring() would.

Why only to numbers and not to all other things, tostring() gives an answer
for,
like specifically "nil", and "true"/"false"?

Timing it, I find that

    "text " .. x

with x a number is measurably faster than

    "text " .. tostring(x)

Having seen concatenation fail on nil or booleans, some people develop the
habit to tostring() everything, including numbers.

I think, the concatenation (and %s in format and ...)
should uniformly tostring() everything that is possible.

Thanks
Dirk