1. RE: more match() problems
Mike Nelson wrote:
>
>
> Derek Parnell wrote:
>
> <snip>
> > match() LOOKS FOR SLICES - ALWAYS.
> > find() LOOKS FOR ELEMENTS - ALWAYS.
> </snip>
>
> This is entirely correct and is as it should be. I would further
> emphasize
> that find() and match() only work at the top level.
>
> Since match() always looks for slices, an atom as the first parameter is
> and
> should be an error. An empty sequence as the first parameter is also an
> error--a return of 0 is preferable, as it would eliminate some special
> case
> checking from code using match().
>
> -- Mike Nelson
>
>
Hi Mike,
I see your point.
I really only wanted match to be able to do
i=match("",sequence) --rets 0
That's really all i wanted.
In every case i think i've ever used match, ive used
a variable sequence as the first argument, so i guess im
not as worried about having it allow an atom as the first
argument as some other people might be.
Take care,
Al
2. RE: more match() problems
Derek Parnell wrote:
>
>
> On Wed, 28 May 2003 07:43:20 +0000, Al Getz <Xaxo at aol.com> wrote:
>
> >
> > Hello again,
> >
> > Looking closer at the match() function,
> > i find that it doesnt really work very well
> > unless you are only using it on one level sequences (like {1,2,3} or
> > "abc").
> >
> > Untill this point, i dont think i ever used it
> > for anything else, but since we were looking at it
> > anyway i thought i would mention this.
> >
> > match({2,3},{1,2,3})
> >
> > returns the number 2, because the 'slice' was found
> > in the second sequence. Works fine.
> >
> > Now,
> >
> > match({{1,2,3}},{{1,2,3}})
> >
> > returns the number 1, because again the 'slice' (although this time
> > deeper) was found in
> > the second sequence. Works fine.
> >
> > Nowwwwwwwww...
> >
> > what does
> >
> > match({{2,3}},{{1,2,3}})
> >
> > return? (same example with the 1 missing in first arg)
> >
> > If you said the number 2, you are correct, because
> > the 'slice' could be found in the second sequence
> > at the required level, right???
> >
> > Well, guess again!
> > The Eu match command returns a big fat zero!
> >
> > Yes, that's right,
> >
> > i=match({{1,2,3}},{{1,2,3}}) -- rets 1
> > but
> > i=match({{2,3}},{{1,2,3}}) -- rets 0
> >
> >
> > Care to try to figure that out?
>
> Sure. Let's look at all the possible slices of {{1,2,3}}, shall we.
>
> s = {{1,2,3}}
> Length of s is 1, right?
> So then there is only one slice, namely s[1..1] and its value is
> {{1,2,3}}.
>
> Now the LHS side of your match was {{2,3}}. Can you locate this value in
>
> any of the slices (all one of them) of s?
>
>
> > I guess i went too far in assuming there was a method
> > to the madness.
> >
> > Anomaly number 97316 and counting...
>
> Not an anomaly at all. I keep saying this but it doesn't seem to be
> making
> it across the language barrier...
>
> match() LOOKS FOR SLICES - ALWAYS.
> find() LOOKS FOR ELEMENTS - ALWAYS.
>
>
> --
>
> cheers,
> Derek Parnell
>
Yeah? no kiddin???
I realized i made the same mistake Kat made, but
the post went through already, and there is no
way to edit a post on Topica like there is in other
message boards i post on. Once you hit that
button, that's it.
It's a shame it solicited a response, because
that response was a wasted effort.
Thanks anyway,
Al
3. RE: more match() problems
Derek Parnell wrote:
>
>
> On Wed, 28 May 2003 07:43:20 +0000, Al Getz <Xaxo at aol.com> wrote:
>
> >
> > Hello again,
> >
> > Looking closer at the match() function,
> > i find that it doesnt really work very well
> > unless you are only using it on one level sequences (like {1,2,3} or
> > "abc").
> >
> > Untill this point, i dont think i ever used it
> > for anything else, but since we were looking at it
> > anyway i thought i would mention this.
> >
> > match({2,3},{1,2,3})
> >
> > returns the number 2, because the 'slice' was found
> > in the second sequence. Works fine.
> >
> > Now,
> >
> > match({{1,2,3}},{{1,2,3}})
> >
> > returns the number 1, because again the 'slice' (although this time
> > deeper) was found in
> > the second sequence. Works fine.
> >
> > Nowwwwwwwww...
> >
> > what does
> >
> > match({{2,3}},{{1,2,3}})
> >
> > return? (same example with the 1 missing in first arg)
> >
> > If you said the number 2, you are correct, because
> > the 'slice' could be found in the second sequence
> > at the required level, right???
> >
> > Well, guess again!
> > The Eu match command returns a big fat zero!
> >
> > Yes, that's right,
> >
> > i=match({{1,2,3}},{{1,2,3}}) -- rets 1
> > but
> > i=match({{2,3}},{{1,2,3}}) -- rets 0
> >
> >
> > Care to try to figure that out?
>
> Sure. Let's look at all the possible slices of {{1,2,3}}, shall we.
>
> s = {{1,2,3}}
> Length of s is 1, right?
> So then there is only one slice, namely s[1..1] and its value is
> {{1,2,3}}.
>
> Now the LHS side of your match was {{2,3}}. Can you locate this value in
>
> any of the slices (all one of them) of s?
>
>
> > I guess i went too far in assuming there was a method
> > to the madness.
> >
> > Anomaly number 97316 and counting...
>
> Not an anomaly at all. I keep saying this but it doesn't seem to be
> making
> it across the language barrier...
>
> match() LOOKS FOR SLICES - ALWAYS.
> find() LOOKS FOR ELEMENTS - ALWAYS.
>
>
> --
>
> cheers,
> Derek Parnell
>
Yeah? no kiddin???
I realized i made the same mistake Kat made, but
the post went through already, and there is no
way to edit a post like there is in other
message boards i post on. Once you hit that
button, that's it.
It's a shame it solicited a response, because
that response was a wasted effort.
Thanks anyway,
Al
4. RE: more match() problems
- Posted by gertie at visionsix.com
May 28, 2003
On 28 May 2003, at 18:05, Al Getz wrote:
<snip>
> > > I guess i went too far in assuming there was a method
> > > to the madness.
> > >
> > > Anomaly number 97316 and counting...
> >
> > Not an anomaly at all. I keep saying this but it doesn't seem to be
> > making
> > it across the language barrier...
> >
> > match() LOOKS FOR SLICES - ALWAYS.
> > find() LOOKS FOR ELEMENTS - ALWAYS.
> >
> >
> > --
> >
> > cheers,
> > Derek Parnell
> >
>
> Yeah? no kiddin???
>
> I realized i made the same mistake Kat made, but
> the post went through already, and there is no
> way to edit a post on Topica like there is in other
> message boards i post on. Once you hit that
> button, that's it.
How i'd like to see it happen isn't a mistake. Presuming it would actually
behave that way would be a mistake. Rather like the news report here: "you
don't expect government employees to mistreat you on the phone", but i do
expect that. I don't think it's right that they do, but i expect them to.
> It's a shame it solicited a response, because
> that response was a wasted effort.
Was not wasted! Other replies were generated, there may be a consensus
that match(atom,sequence) should fall thru to find(). Besides, Derek has a
way with that south hemisphere english that is clearer than Canadian
sometimes.
Kat
5. RE: more match() problems
- Posted by gertie at visionsix.com
May 28, 2003
On 28 May 2003, at 18:14, Al Getz wrote:
>
>
> Mike Nelson wrote:
> >
> >
> > Derek Parnell wrote:
> >
> > <snip>
> > > match() LOOKS FOR SLICES - ALWAYS.
> > > find() LOOKS FOR ELEMENTS - ALWAYS.
> > </snip>
> >
> > This is entirely correct and is as it should be. I would further
> > emphasize
> > that find() and match() only work at the top level.
> >
> > Since match() always looks for slices, an atom as the first parameter is and
> > should be an error. An empty sequence as the first parameter is also an
> > error--a return of 0 is preferable, as it would eliminate some special case
> > checking from code using match().
> >
> > -- Mike Nelson
> >
> >
> Hi Mike,
>
> I see your point.
>
> I really only wanted match to be able to do
> i=match("",sequence) --rets 0
>
> That's really all i wanted.
Me to, everything else would be gravey.
> In every case i think i've ever used match, ive used
> a variable sequence as the first argument, so i guess im
> not as worried about having it allow an atom as the first
> argument as some other people might be.
I always do something like this:
if atom(x)
then z = match({x},y)
else z = match(x,y)
end if
or
if sequence(x)
then z = match(x,y)
else exit -- cannot use a goto eoroutine here!
end if
If i don't, sure as heck x will be "" eventually and the app will crash. Testing
for equal(x,"") or (length(x) = 0 ) repeatedly, over and over, ad nauseum
helps(?) too.
Kat
