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bug#15074: 24.3; Possible typo in the Elisp Reference Manual - section 2
From: |
Eli Zaretskii |
Subject: |
bug#15074: 24.3; Possible typo in the Elisp Reference Manual - section 2.3.3.4 |
Date: |
Mon, 12 Aug 2013 14:38:08 +0300 |
> Date: Mon, 12 Aug 2013 09:38:57 +0100
> From: Sian Mountbatten <poenikatu@fastmail.co.uk>
>
> In section 2.3.3.4 of the Elisp Reference Manual, this sentence occurs:
> The integer that represents such a character has the $2^{27}$ bit
> set.
>
> I have expressed the number using the TeX/LaTeX manner. The
> point is that, in the following paragraph, the text refers to the
> $2^7$ bit. I suspect, therefore, that the 27 mentioned should really
> be 7.
No, it's not a typo: the META modifier bit of a character is indeed
0x8000000.
> If 27 was intended, that would mean that char tables would have
> to accommodate more than 134 million characters! Surely not!
As a matter of fact, char tables can accommodate all the Unicode
character space, but they do that in an efficient way, not by
allocating a flat array. Nevertheless, the META bit is unrelated to
the capacity of a char table, since modifiers are not stored there.