RE: html tree question. clumsy ?
Thanks for your info Rob. But look at what you wrote: "I'm pretty sure",
"I understand it to mean", "I believe"...
My comments and solutions are based on my _actually_writing_code_ to try
to do the things you muse about, and _it_did_not_work_.
Don't take this the wrong way Rob, I just want to make things clear for
other people reading this who might run into the same problem and/or be
inclined to try it out.
- - Martin
> -Original Message-
> From: Rob Dixon [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, September 23, 2003 5:27 PM
> To: [EMAIL PROTECTED]
> Subject: Re: html tree question. clumsy ?
>
>
> Martin Thurn wrote:
> > I ran into similar problems for my module WWW::Search.
> > No, out-of-the-box you can not re-use an
> HTML::TreeBuilder object to parse
> > a new file.
>
> I'm pretty sure you're wrong about that. HTML::TreeBuilder subclasses
> HTML::Parser, which provides the 'new', 'parse',
> 'parse_file', and 'eof'
> methods. The documentation says:
>
> After $p->eof has been called, the parse() and
> parse_file() methods
> can be invoked to feed new documents with the parser object.
>
> which is poor English, but I understand it to mean that, once
> the 'eof'
> method has been called, any further calls to 'parse' or 'parse_file'
> will create a new HTML tree from scratch.
>
> > BUT you can use the following code as a "reset". I.e. call
> > parse, muck with the tree, do the following four lines, and
> call parse
> > again. This does the same as new() but without changing
> the store_comments,
> > store_pis settings, etc:
> >
> > $self->{'_head'} = $self->insert_element('head',1);
> > $self->{'_pos'} = undef; # pull it back up
> > $self->{'_body'} = $self->insert_element('body',1);
> > $self->{'_pos'} = undef; # pull it back up again
>
> HTML::Parser will itself insert any implicit , and
> tags when further input is parsed.
>
> > The reason you can't re-use your HTML::Element is because it's a
> > reference, and when the tree gets deleted, your Element
> gets deleted right
> > along with it.
>
> Once you have called $tree->delete the object no longer exists, but I
> believe $tree->delete_content or $tree->eof will allow you to reuse
> the same object for parsing a new document.
>
> Rob
>
>
Re: html tree question. clumsy ?
At 09:42 AM 2003-09-23, James.Q.L wrote:
1. will $tree->parse_file(parse a new file) will overwrite the old parsed
$tree content?
No, don't try that. You can call parse_file on a $tree only once. As far
as I remember, there's no re-using it.
so that i dont have to delete the tree in the sub?
Why not just delete the tree?
As to your question here:
## why can't keep it outside ?/
my $literal = HTML::Element->new('~literal','text' => $insert);
I think because once you insert the $literal object into a tree, then when
you later destroy the tree, that deletes that $literal object, too.
(Deleting a tree basically means deleting every attribute in every node in
the tree.)
--
Sean M. Burkehttp://search.cpan.org/~sburke/
Re: html tree question. clumsy ?
--- Rob Dixon <[EMAIL PROTECTED]> wrote: > Martin Thurn wrote: > > I ran into similar problems for my module WWW::Search. > > No, out-of-the-box you can not re-use an HTML::TreeBuilder object to parse > > a new file. > > I'm pretty sure you're wrong about that. HTML::TreeBuilder subclasses > HTML::Parser, which provides the 'new', 'parse', 'parse_file', and 'eof' > methods. The documentation says: > > After $p->eof has been called, the parse() and parse_file() methods > can be invoked to feed new documents with the parser object. > > which is poor English, but I understand it to mean that, once the 'eof' > method has been called, any further calls to 'parse' or 'parse_file' > will create a new HTML tree from scratch. but from HTML::TreeBuilder, " $root->eof() This signals that you're finished parsing content into this tree; this runs various kinds of crucial cleanup on the tree. This is called for you when you call $root->parse_file(...), but not when you call $root->parse(...). So if you call $root->parse(...), then you must call $root->eof() once you've finished feeding all the chunks to parse(...), and before you actually start doing anything else with the tree in $root." it said 'This is called for you when you call $root->parse_file'. > > The reason you can't re-use your HTML::Element is because it's a > > reference, and when the tree gets deleted, your Element gets deleted right > > along with it. > > Once you have called $tree->delete the object no longer exists, but I > believe $tree->delete_content or $tree->eof will allow you to reuse > the same object for parsing a new document. > > Rob > i tried both delete_content and eof, it either yield error or the first file being parsed is written to the rest of parsing file. something like this define new tree $tree in new sub, parse file with $tree, do something , then called $tree->delete_content or/and $tree->eof Qiang __ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com
Re: html tree question. clumsy ?
James.Q.L wrote:
>
> Thurn, Martin wrote:
> >
> > I ran into similar problems for my module WWW::Search.
> > No, out-of-the-box you can not re-use an HTML::TreeBuilder object to parse
> > a new file. BUT you can use the following code as a "reset". I.e. call
> > parse, muck with the tree, do the following four lines, and call parse
> > again. This does the same as new() but without changing the store_comments,
> > store_pis settings, etc:
> >
> > $self->{'_head'} = $self->insert_element('head',1);
> > $self->{'_pos'} = undef; # pull it back up
> > $self->{'_body'} = $self->insert_element('body',1);
> > $self->{'_pos'} = undef; # pull it back up again
>
> i will look into how that can be added to $tree later.
> but a reset method from HTML::TreeBuilder would be nice.
As per my previous post, I think $tree->eof or $tree->delete_content will
do the trick.
> > The reason you can't re-use your HTML::Element is because it's a
> > reference, and when the tree gets deleted, your Element gets deleted right
> > along with it.
> >
> > - - Martin Thurn
> >
>
> just found that $h->clone can get around this. too bad i can't do the same to a tree
> before it
> parses the file.
>
> from HTML::Element,
>
> You are free to clone HTML::TreeBuilder trees, just as long as: 1) they're done
> being parsed, or
> 2) you don't expect to resume parsing into the clone. (You can continue parsing into
> the original;
> it is never affected.)
>
> just to make sure, (english isn't my first language) does it say that i can't clone
> a tree if it
> doesn't parse something?
No. What this is saying is that you can't do:
my $tree = new HTML::TreeBuilder;
$tree->parse($string1);
$tree->parse($string2);
my $tree2 = $tree->clone;
$tree2->parse($string3);
But, here, you could write
$tree->parse($string4);
In other words, you can't carry on parsing HTML text into a cloned
tree, but the original tree is unaffected.
HTH,
Rob
Re: html tree question. clumsy ?
Martin Thurn wrote:
> I ran into similar problems for my module WWW::Search.
> No, out-of-the-box you can not re-use an HTML::TreeBuilder object to parse
> a new file.
I'm pretty sure you're wrong about that. HTML::TreeBuilder subclasses
HTML::Parser, which provides the 'new', 'parse', 'parse_file', and 'eof'
methods. The documentation says:
After $p->eof has been called, the parse() and parse_file() methods
can be invoked to feed new documents with the parser object.
which is poor English, but I understand it to mean that, once the 'eof'
method has been called, any further calls to 'parse' or 'parse_file'
will create a new HTML tree from scratch.
> BUT you can use the following code as a "reset". I.e. call
> parse, muck with the tree, do the following four lines, and call parse
> again. This does the same as new() but without changing the store_comments,
> store_pis settings, etc:
>
> $self->{'_head'} = $self->insert_element('head',1);
> $self->{'_pos'} = undef; # pull it back up
> $self->{'_body'} = $self->insert_element('body',1);
> $self->{'_pos'} = undef; # pull it back up again
HTML::Parser will itself insert any implicit , and
tags when further input is parsed.
> The reason you can't re-use your HTML::Element is because it's a
> reference, and when the tree gets deleted, your Element gets deleted right
> along with it.
Once you have called $tree->delete the object no longer exists, but I
believe $tree->delete_content or $tree->eof will allow you to reuse
the same object for parsing a new document.
Rob
RE: html tree question. clumsy ?
--- "Thurn, Martin" <[EMAIL PROTECTED]> wrote:
> I ran into similar problems for my module WWW::Search.
> No, out-of-the-box you can not re-use an HTML::TreeBuilder object to parse
> a new file. BUT you can use the following code as a "reset". I.e. call
> parse, muck with the tree, do the following four lines, and call parse
> again. This does the same as new() but without changing the store_comments,
> store_pis settings, etc:
>
> $self->{'_head'} = $self->insert_element('head',1);
> $self->{'_pos'} = undef; # pull it back up
> $self->{'_body'} = $self->insert_element('body',1);
> $self->{'_pos'} = undef; # pull it back up again
i will look into how that can be added to $tree later.
but a reset method from HTML::TreeBuilder would be nice.
> The reason you can't re-use your HTML::Element is because it's a
> reference, and when the tree gets deleted, your Element gets deleted right
> along with it.
>
> - - Martin Thurn
>
just found that $h->clone can get around this. too bad i can't do the same to a tree
before it
parses the file.
from HTML::Element,
You are free to clone HTML::TreeBuilder trees, just as long as: 1) they're done being
parsed, or
2) you don't expect to resume parsing into the clone. (You can continue parsing into
the original;
it is never affected.)
just to make sure, (english isn't my first language) does it say that i can't clone a
tree if it
doesn't parse something?
Qiang
__
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com
RE: html tree question. clumsy ?
I ran into similar problems for my module WWW::Search.
No, out-of-the-box you can not re-use an HTML::TreeBuilder object to parse
a new file. BUT you can use the following code as a "reset". I.e. call
parse, muck with the tree, do the following four lines, and call parse
again. This does the same as new() but without changing the store_comments,
store_pis settings, etc:
$self->{'_head'} = $self->insert_element('head',1);
$self->{'_pos'} = undef; # pull it back up
$self->{'_body'} = $self->insert_element('body',1);
$self->{'_pos'} = undef; # pull it back up again
The reason you can't re-use your HTML::Element is because it's a
reference, and when the tree gets deleted, your Element gets deleted right
along with it.
- - Martin Thurn
