Re: [Scheme-reports] fresh empty strings

[Ray Dillinger <bear@x>]

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On 01/21/2012 05:47 AM, Andy Wingo wrote:

> An empty string (vector, bytevector, etc) does not have any locations
> for the characters, but it does have a location for the length.

Nope.  While most implementations do store a length, it
isn't a "location" according to the language of the standard --
ie, it cannot be mutated directly and there is nothing that
is required to treat it as a location rather than as a value.

Because the length of all empty vectors is equal, storing it
multiple times is strictly useless.  Ditto empty strings.

I say it's perfectly fine (desirable, even) for an implementation
to have a distinguished immediate value for the empty string,
the empty vector, etc, the same way there is an immediate value
for the empty list, and for all instances of such entities to
be eq? if they are of the same type.

				Bear


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