Re: REs as generators
On Thu, Dec 12, 2002 at 10:35:47AM +1100, Damian Conway wrote: Dave Storrs wrote: - the ability for the programmer to set limiters (??better name??) on the junction, which will specify how the junction should collapse--e.g. always collapse to the lowest/highest value that hasn't been supplied yet, or to the lowest/highest unsupplied value that causes a particular code block to return true, or whatever. Junctions don't collapse. They distribute. Remember: Junctions Aren't Quantum. Ah. Obviously, I don't know JAQ. (sorry) However, I don't believe this answers my question...or, more likely, I am just misunderstanding junctions. I believe that this code: my $i = one(7...); print $i; Is roughly equivalent to this English: - declare a lexical variable $i - create a junction. The states of the junction are (7..Inf). The type of the junction is one - assign the junction to $i - distribute the junction [that still doesn't sound right, but ok] by choosing one of the states (at random??) - print the number chosen in the previous step. First of all, am I correct about this? Second, what I was originally asking is this: could there be some way for the programmer to attach a (method/code block/sub/whatever) to the junction, such that when the state is chosen, the default method of choosing a state is overriden by the code supplied by the programmer. --Dks
Re: REs as generators
Mailing-List: contact [EMAIL PROTECTED]; run by ezmlm Date: Wed, 11 Dec 2002 17:24:54 -0800 From: Dave Storrs [EMAIL PROTECTED] Mail-Followup-To: [EMAIL PROTECTED] [EMAIL PROTECTED] Content-Disposition: inline X-SMTPD: qpsmtpd/0.20, http://develooper.com/code/qpsmtpd/ On Thu, Dec 12, 2002 at 10:35:47AM +1100, Damian Conway wrote: Dave Storrs wrote: - the ability for the programmer to set limiters (??better name??) on the junction, which will specify how the junction should collapse--e.g. always collapse to the lowest/highest value that hasn't been supplied yet, or to the lowest/highest unsupplied value that causes a particular code block to return true, or whatever. Junctions don't collapse. They distribute. Remember: Junctions Aren't Quantum. Ah. Obviously, I don't know JAQ. (sorry) However, I don't believe this answers my question...or, more likely, I am just misunderstanding junctions. I believe that this code: my $i = one(7...); print $i; Is roughly equivalent to this English: - declare a lexical variable $i - create a junction. The states of the junction are (7..Inf). The type of the junction is one - assign the junction to $i - distribute the junction [that still doesn't sound right, but ok] by choosing one of the states (at random??) - print the number chosen in the previous step. No collapsing. Not without an explicit .pick. It would call Cprint with each of the values of $i (unless print was designed to accept a junction, in which case you'd get some stringification/serialization of the junction). Cprint would return a one() junction of whatever print returned after printing each value, but what do you care, they're all in the garbage anyway? :) First of all, am I correct about this? No. As I just explained. Second, what I was originally asking is this: could there be some way for the programmer to attach a (method/code block/sub/whatever) to the junction, such that when the state is chosen, the default method of choosing a state is overriden by the code supplied by the programmer. Your question is now irrelevant. Luke
Re: REs as generators
On Wed, Dec 11, 2002 at 06:53:20PM -0800, Randal L. Schwartz wrote:
Rich == Rich Morin [EMAIL PROTECTED] writes:
Rich On occasion, I have found it useful to cobble up a little language
Rich that allows me to generate a list of items, using a wild-card or some
Rich other syntax, as:
Richfoo[0-9][0-9] yields foo00, foo01, ...
Rich I'm wondering whether Perl should have a similar capability, using REs.
Well, here's a cheap way:
my @list = glob ('foo{0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9}');
:-)
Cheap in terms of programmer effort. But it uses a lot of RAM in perl5.
Enough the the golfers get upset that some of the shortest solutions don't
work because they run out of swap. IIRC Hugo is lucky because his auction of
an improvement for perl 5.10 could easily have ended up with a bidder who
wanted multiway globs to work in much less RAM.
Nicholas Clark
Re: REs as generators
Luke Palmer wrote: LP my $foos = 'foo' ~ any(0..9) ~ any(0..9); Actually $foos will be a junction. You could use Cstates to get each state out of the junction in an array. my @foos = states $foos; Luke's right on target (as usual :-). Just one slight niggle. I suspect Cstates may be a method only, so that would be either: my @foos = states $foos:; or: my @foos = $foos.states; Though, I suppose we might argue that Cstates is as fundamental to Perl 6 as Cgrep or Csort, and so ought to have a built-in as well. Hmmm. Damian
Re: REs as generators
Date: Wed, 11 Dec 2002 19:15:53 +1100 From: Damian Conway [EMAIL PROTECTED] I suspect Cstates may be a method only, so that would be either: my @foos = states $foos:; or: my @foos = $foos.states; Though, I suppose we might argue that Cstates is as fundamental to Perl 6 as Cgrep or Csort, and so ought to have a built-in as well. Hmmm. Can junctions have methods? How do you tell the difference between calling a junction's method and calling a method on each of its states? Luke
Re: REs as generators
On Tue, Dec 10, 2002 at 03:38:58PM -0800, Rich Morin wrote: On occasion, I have found it useful to cobble up a little language that allows me to generate a list of items, using a wild-card or some other syntax, as: foo[0-9][0-9] yields foo00, foo01, ... I'm wondering whether Perl should have a similar capability, using REs. Will Perl6 still have the increment a string ability? I can't count the number of times that's been my saving grace when I needed to portably and easily generate a unique filename. --Dks
Re: REs as generators
Luke Palmer asked: Can junctions have methods? If we decide they can, yes. ;-) How do you tell the difference between calling a junction's method and calling a method on each of its states? If it's a method of the class Junction (or one of its four subclasses) then it's a method call on the junction itself. If it's not defined in the built-in class, then it's a method call distributed over the states of the junction. Damian
Re: REs as generators
Dave Storrs wrote: On Tue, Dec 10, 2002 at 10:37:10PM -0700, Luke Palmer wrote: Why use regexen when you can just use junctions? my $foos = 'foo' ~ any(0..9) ~ any(0..9); At what moment does a junction actually create all of its states? Hmm...perhaps a clearer way to say that is At what moment does a junction allocate memory for, and initialize that memory with, all of its states? That will have to be done lazily in some cases at least: if $input == any(13...); so maybe it should be done lazily in all cases. - the ability for the programmer to set limiters (??better name??) on the junction, which will specify how the junction should collapse--e.g. always collapse to the lowest/highest value that hasn't been supplied yet, or to the lowest/highest unsupplied value that causes a particular code block to return true, or whatever. Junctions don't collapse. They distribute. Remember: Junctions Aren't Quantum. Damian
Re: REs as generators
Rich == Rich Morin [EMAIL PROTECTED] writes:
Rich On occasion, I have found it useful to cobble up a little language
Rich that allows me to generate a list of items, using a wild-card or some
Rich other syntax, as:
Richfoo[0-9][0-9] yields foo00, foo01, ...
Rich I'm wondering whether Perl should have a similar capability, using REs.
Well, here's a cheap way:
my @list = glob ('foo{0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9}');
:-)
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
[EMAIL PROTECTED] URL:http://www.stonehenge.com/merlyn/
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
Re: REs as generators
RM == Rich Morin [EMAIL PROTECTED] writes: RM On occasion, I have found it useful to cobble up a little language RM that allows me to generate a list of items, using a wild-card or some RM other syntax, as: RMfoo[0-9][0-9] yields foo00, foo01, ... RM I'm wondering whether Perl should have a similar capability, using REs. the problem is that regexes can be very wide in accepting data but your needs are narrow. how do you expand . or .* ? what you want is more like a macro facility. my favorite macro support came with macro-11. it had .IRPC (indefinite repeat char) so you could do this (untested and surely bad syntax :) .IRPC $A, 0123456789 .IRPC $B, 0123456789 .ASCII 'foo$A$B' .END .END there has been debate here about what level of macro support to have. we can't do lisp's as we don't have easy access to generated code and we have to be better than cpp which is useless IMO as you don't have nested calls and loops. but for stuff like table and data structure building we should have some way to generate perl source/data with decent control. uri -- Uri Guttman -- [EMAIL PROTECTED] http://www.stemsystems.com - Stem and Perl Development, Systems Architecture, Design and Coding Search or Offer Perl Jobs http://jobs.perl.org
Re: REs as generators
On Tue, Dec 10, 2002 at 03:38:58PM -0800, Rich Morin wrote:
On occasion, I have found it useful to cobble up a little language
that allows me to generate a list of items, using a wild-card or some
other syntax, as:
foo[0-9][0-9] yields foo00, foo01, ...
I'm wondering whether Perl should have a similar capability, using REs.
Dominus has an example of an 'odometer' written using closures. If
you want to specify a simple sequence like this using a regex, then
you need to parse the regex (but in reverse).
Alternatively, you could write a generic odometer generator generator
that takes a series of scalars and lists:
my $generator = make_generator('foo', [0..9], [0..9]);
while ($_ = $generator-()) {
## progressively generate foo00, foo01, ...
}
Z.
Re: REs as generators
Mailing-List: contact [EMAIL PROTECTED]; run by ezmlm
Date: Tue, 10 Dec 2002 21:07:34 -0500
From: Adam Turoff [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Content-Disposition: inline
X-SMTPD: qpsmtpd/0.20, http://develooper.com/code/qpsmtpd/
On Tue, Dec 10, 2002 at 03:38:58PM -0800, Rich Morin wrote:
On occasion, I have found it useful to cobble up a little language
that allows me to generate a list of items, using a wild-card or some
other syntax, as:
foo[0-9][0-9] yields foo00, foo01, ...
I'm wondering whether Perl should have a similar capability, using REs.
Dominus has an example of an 'odometer' written using closures. If
you want to specify a simple sequence like this using a regex, then
you need to parse the regex (but in reverse).
Alternatively, you could write a generic odometer generator generator
that takes a series of scalars and lists:
my $generator = make_generator('foo', [0..9], [0..9]);
while ($_ = $generator-()) {
## progressively generate foo00, foo01, ...
}
Z.
It only differentiates between arrays an non-, but it would be trivial
to add other semantics, if you figure out what they actually are.
sub make_generator(*@pats) {
return unless @pats;
given shift @pats - $pattern {
when Array {
for @$pattern - $item {
my $generator = make_generator(@pats);
yield $item ~ $_ for $generator;
}
}
otherwise {
my $generator = make_generator(@pats);
yield $pattern ~ $_ for $generator;
}
}
}
You'd use it just like I did in the sub, as an iterator.
This would have been dastardly complex without corouties. :-)
Luke
Re: REs as generators
Mailing-List: contact [EMAIL PROTECTED]; run by ezmlm Date: Tue, 10 Dec 2002 15:38:58 -0800 From: Rich Morin [EMAIL PROTECTED] X-SMTPD: qpsmtpd/0.20, http://develooper.com/code/qpsmtpd/ On occasion, I have found it useful to cobble up a little language that allows me to generate a list of items, using a wild-card or some other syntax, as: foo[0-9][0-9] yields foo00, foo01, ... I'm wondering whether Perl should have a similar capability, using REs. Why use regexen when you can just use junctions? my $foos = 'foo' ~ any(0..9) ~ any(0..9); That's a bit shorter that the code sample I just wrote... not by much though :-P. Unfortunately, this one doesn't come in order, but a Csort should fix that. We have a Ipowerful language on our hands, people. Luke
Re: REs as generators
LP == Luke Palmer [EMAIL PROTECTED] writes: LP Why use regexen when you can just use junctions? LP my $foos = 'foo' ~ any(0..9) ~ any(0..9); should that be @foos or will it make an anon list of the foos and store the ref? LP We have a Ipowerful language on our hands, people. i know but changing my brane to think like that will take some time and practice. i brought up a macro idea but this is what i wanted to do with maps or nested loops. uri -- Uri Guttman -- [EMAIL PROTECTED] http://www.stemsystems.com - Stem and Perl Development, Systems Architecture, Design and Coding Search or Offer Perl Jobs http://jobs.perl.org
Re: REs as generators
LP == Luke Palmer [EMAIL PROTECTED] writes: LP my $foos = 'foo' ~ any(0..9) ~ any(0..9); should that be @foos or will it make an anon list of the foos and store the ref? LP Actually $foos will be a junction. You could use Cstates to get LP each state out of the junction in an array. LP my @foos = states $foos; that is going to take a while to become normalized in my neurons. very useful but not in my vernacular yet. uri -- Uri Guttman -- [EMAIL PROTECTED] http://www.stemsystems.com - Stem and Perl Development, Systems Architecture, Design and Coding Search or Offer Perl Jobs http://jobs.perl.org
