ietf-mta-filters
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Re: "extensible" grammar

1998-01-25 00:51:06
So I see this as a proposal to constrain the human readability of the
script for all time in order to save a few programmer hours.  This seems
like a really bad tradeoff to me.

Your argument seems inconsistent to me.  First you suggest that a
"multi-level" grammar is complex and hard to understand, then you
argue that it will "save a few programmer hours", (one can only assume
that's because it's actually *less complex*).

You're confusing any number of things here. For one thing, a multi-level
grammar can be quite easy to parse, especially when you only do the outer
generic level. This does not, however, mean that the thing is simple or that
people -- even implementors -- really understand what is going on. What seems
to happen is that they think they do but they don't.

We have decades of experience with one multi-level grammar called RFC822 that
argue this point rather overwhelmingly.

Second, the point is that parsing is the *easy* part. All this whoopla about
language syntax is nothing but an attempt to optimize the already-easy part of
the problem, at the expense of grotting up the hard part -- the semantics --
considerably. Shaving 10% off of the 10% part while adding 10% to the 90% part
is a bad idea, and that's what I see happening here.

But you're opposed to that because it "constrains human readability".

The issue with human readability is that people like to have a fair number of
visual cues as to what is going on. The use of a very regular syntax tends to
compromise the ability to add such cues.

Then, in another note,
you argue that less than 5% of users will write their own scripts, which
leaves me wondering why human readability matters so much....

Once again you're confusing different things. Yes, it is true that only a small
percentage of users (I expect the number to be far lower than 5%) will write
their own scripts. But this only means that it is critically important that the
language appeal to the authors of script generators. This is a fairly demanding
audience, and if the language looks awkard (and I think the latest proposal
looks _very_ awkward) they aren't going to like it.

                                Ned

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