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- Subject: Conversion of strings to numbers and numbers to strings.
- From: David Jones <drj@...>
- Date: Tue, 30 May 2006 12:04:12 +0100
I find that the reference manual for Lua 5.1 is disturbingly vague on
the matter of converting numbers to strings and strings to numbers.
Pretty much all it says is in section 2.2.1, string to number is done
"following the usual conversion rules", and number to string is done
"in a reasonable format".
I realise that the Lua team cannot reasonably make it absolutely
precise, because even if luaconf.h has not been modified by the user,
the underlying operations depend on the C library. But I feel that
some more could be said, for example:
Reasonable sized integers will be converted to a string that does not
include a decimal point.
When converting strings to numbers, preceding and trailing whitespace
When converting strings to numbers, an optional minus sign is
Both hexadecimal and decimal (floating point) conversions are possible.
I feel that they would be useful additions to the manual.
By the way, I was surprised by the result of
return '-0x1' + 0
I was even more surprised when it gave a different answer on my PowerPC
OS X machine (where it gives -1) than on an Intel Windows XP machine
(where it gives 4294967295).