WikiDiscuss

On Sat, Dec 18, 2004 at 08:01:57PM -0500, Pierre Abbat wrote:
> On Saturday 18 December 2004 18:52, Robin Lee Powell wrote:
> > On Sat, Dec 18, 2004 at 08:13:24AM -0500, Pierre Abbat wrote:
> > > Is a C program sufficiently unambiguous?
> >
> > Absolutely not. It's not a formalism, it's a piece of code.
>
> Is there a formalism that I can translate valfendi into?

I don't know what formalisms you know, so I can't really answer
that.

> The problem appears to be that you and I think differently.

Yes. I tried to explain this to you when I was asking you question
about the valfendi algorithm some months ago. I gave up after a
while; I couldn't figure out what you were talking about.

> When I wrote valfendi, I separated, as well as I could, the
> operation of splitting a stream of phonemes into words from the
> operation of determining whether those words are valid. This is
> easier for me to understand. To do that, I have to find the string
> that matches one regular expression (or parsing expression or
> whatever) at the beginning of the remaining text, then check
> whether that string, no more and no less, matches another
> expression.

That is a fundamentally algorithmic way of thinking, yes.

> For instance, if the text is /dAmymlongEnavau/, the first
> expression matches /dAmymlongEna/, which the second does not
> match, although it does match /dAmymlo/. I could write a PEG with
> two expressions, called lex-brivla and valid-brivla, and then
> write "brivla <- &lex-brivla valid-brivla", but that would match
> /dAmymlongEnavau/ and consume /dAmymlo/, even though lex-brivla
> matched /dAmymlongEna/. Trying to do both checks at once is
> confusing to me, though you seem to understand it.

You've taken brivla out of context, so it's hard to go from what you
just said to something useful, but I assume that the top level is
something like:

morphology <- word*

word <- cmavo / brivla / cmene

Then with your brivla, it only consumes dAmymlo, but that's fine
because the next run of "word" will start at "ng" (which will
probably cause breakage, but that's fine I hope). I have no idea if
this helps you; as with the algorithm itself, I'm not certain I
actually have any real idea what you're asking.

One way to do what you want, I suppose, would be to add another
stage to the parser. Right now, it's got a morphology stage and a
grammar stage. You could break morphology into word-grouping and
word-recognition stages. I have not the slightest idea why this
approach is useful however.

> So, is there something sufficiently programming-language-like that
> I can check that it's doing the same as valfendi,

See, umm, that's impossible. There is no way, in general, to
compare to non-trivial programs to show that they are doing the same
thing. This would be the whole reason I like formalisms.

-Robin