Does anyone has already seen a non mutable String based on std::string - Page 2

Vincent RICHOMME

Hi,

I am currently implementing some basic classes from .NET into modern C++.
And I would like to know if someone would know a non mutable string class.

May 28 '06

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3157

Roland Pibinger

On 28 May 2006 10:57:50 -0700, "kwikius" >You might want to look at
The most popular downloads in the Boost

Vault, where fixed_string was most popular download:

http://tinyurl.com/rstoa

Note that the version there was reviewed but not accepted:

http://www.boost.org/more/formal_review_schedule.html
Grande confusione! boost::fixed_st ring is not an immutable string
class/template. The mentioned Boost library is boost::const_st ring<>
(which, of course, is not an accepted Boost library ;-).
The reasons were IIRC that the implementation had moved away from the
expected concept of a fixed string and so wasnt what potential users
were looking for. However the large amount of downloads suggests that
there is a lot of interest in this functionality. I havent looked at
your version in detail but from looking at the intro, it looks like it
might be worth posting a link to it on the boost developers list to see
whether there is interest. I think there might be.

Thank you for considering my code 'boost-able' but my goal was exactly
the opposite. 'fix_str' consists of very lightweight classes (not
templates, no traits and policies involved) with specified performance
characteristics for copying, assignment and default construction
(unlike std::string).

Best regards,
Roland Pibinger

May 28 '06 #11

Roland Pibinger

On Sun, 28 May 2006 20:58:48 +0200, "Alf P. Steinbach"
<al***@start.no > wrote:

An immutable string class is different from 'std::string const' in that
its operations do not carry the overhead associated with mutability, and
that it supports assignment and thus can be used in standard containers.

Functionalit y-wise it is similar to

typedef boost::shared_p tr<std::string const> ValueString;

Actually, that should be avoided! Immutable objects make only sense as
immutable value objects. In C++ (not in Java) 'value object' means
that an assignment replaces (=mutates) the original object, not just a
reference to it. A totally immutable value object would not be very
useful in C++ (e.g. you could not assign a return value). I asked some
time ago for a name for 'assignable-but-otherwise-immutable-objects'.
The concept seems to be known but there is no established name for it.

http://groups.google.com/group/comp....1ef8b7634c0dc7

Best regards,
Roland Pibinger

May 28 '06 #12

kwikius

Roland Pibinger wrote:

Thank you for considering my code 'boost-able' but my goal was exactly
the opposite.
The opposite of boost-able... ? Would that be unboost-able. Is this a
deliberate aim? :-)
'fix_str' consists of very lightweight classes (not
templates, no traits and policies involved) with specified performance
characteristics for copying, assignment and default construction
(unlike std::string).

AFAIK http://www.boost.org has no requirement that a candidate library
uses templates, traits or policies.

regrads
Andy Little

May 29 '06 #13

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