Re: lvalues and action at distance

Sorry to be a damp squib, but please be very careful what you try to use lvalue refs for.

They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data.

There are other uses, but they can easily start to produce confusing results if you make small mistakes, and that is when you know what you have, and are dealing with. I think blessing them and passing them to others to manipulate is not a good idea.

One of the problems is that they will allow you to replace a substring with either more or less characters than it originally held (just as substr will), but once you have done this, working out what substring the lvref now points to is confusing and will rarely be what you will expect. This is going to get better at some point in the future.

However, if you have two or more lvref pointing to the same string, and one is used to alter the length of overall string, then the substring addressed by the other may or may not change, sometimes in quite radical and confusing ways, depending upon the relationship between the original two. This is not going to change.

Best saved for very localised use, for very specific purposes I think.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?

"Science is about questioning the status quo. Questioning authority".

The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.

Comment on Re: lvalues and action at distance

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Re^2: lvalues and action at distance by blazar (Canon) on Oct 12, 2005 at 07:28 UTC
They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data. They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data. Thank you for the "caveat". Indeed I was thinking of this kind of (what I'd call) "addomesticated" action at distance more in terms of a syntactically and semantically cool possibility to yield yet more WTDI: I was and I am intrigued by the concept and the idea; I was not talking of an actual "need". All in all I realise that my own example may have conveyed the impression that my primary interest was focused on dealing with strings, but that is not the case. It's focused on the implications of (extending) the semantics of "lvalues as something into which you can inject something else to perform some kind of reasonably addomesticated action at distance". (At your own risk and peril, but if you're messing with this kinda stuff, then you're supposed to know what you're doing...)	[reply]

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Re^2: lvalues and action at distance
by blazar (Canon) on Oct 12, 2005 at 07:28 UTC

They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data.
They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data.

Indeed I was thinking of this kind of (what I'd call) "addomesticated" action at distance more in terms of a syntactically and semantically cool possibility to yield yet more WTDI: I was and I am intrigued by the concept and the idea; I was not talking of an actual "need".

All in all I realise that my own example may have conveyed the impression that my primary interest was focused on dealing with strings, but that is not the case. It's focused on the implications of (extending) the semantics of "lvalues as something into which you can inject something else to perform some kind of reasonably addomesticated action at distance". (At your own risk and peril, but if you're messing with this kinda stuff, then you're supposed to know what you're doing...)

[reply]