host statement scope rules (ISC DHCP 3.0.5b1)

Ted Lemon mellon at
Sun Jul 30 06:52:47 UTC 2006

Simon Hobson wrote:
> Which is worrying as I'm sure Ted is one of the people telling us 
> that there is no difference for ages - even if he hasn't said it 
> himself, it's the first time anyone has queried 'accepted wisdom' of 
> the list.

We had a big teaching on this in India just this past month.   In order
to understand the meaning of a statement, you have to consider it in its
context - was what the person was saying intended to convey the literal
meaning of the words, or was it an incomplete or possibly even incorrect
statement that was intended to create a useful and functional degree of
understanding in the mind of the questioner, despite its factual
inaccuracy.   In my case, you also have to consider the degree of mental
affliction present at the time of writing.

The fact is that it's pretty clear to anybody who's read all the source
code and hacked on it on a full-time basis for a couple of years how
scoping works.   To such a person, simple misunderstandings about the
way it works are simply annoying, because the person with the
misunderstanding is obviously just being obstinate.   So a person with
this degree of familiarity with the code may sometimes respond with
perhaps more vehemence and less nuance than is called for to questions
of this nature.

With the benefit of a few years separation from active support of the
product, it is much easier for such a person to admit to the possibility
that perhaps someone who is *not* deeply intimate with the code might
*legitimately* fail to understand in what sense host declarations are
scoped, and in what sense they are not.   And, indeed, that the
existance of this distinction is a bug, and not, as it may have seemed
at the time, a perfectly sensible and understandable implementation detail.

So you can in fact take my most recent expostulation on this matter as
the literal truth, as I understand it, and my previous expostulations as
figurative, in the sense that while they perhaps (dare I hope?) conveyed
what the person asking the question needed to hear, they did not
articulate a complete description of how the system worked.

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