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[OT] Help for a RegEx

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  [OT] Help for a RegEx Fonntuggnio <JoeFonntuggnio@libbbero.it> - 2023-08-02 19:38 +0200
    Re: [OT] Help for a RegEx Christian Gollwitzer <auriocus@gmx.de> - 2023-08-02 20:00 +0200
      Re: [OT] Help for a RegEx MarioCPPP <NoliMihiFrangereMentulam@libero.it> - 2023-08-03 00:52 +0200
    Re: [OT] Help for a RegEx Paavo Helde <eesnimi@osa.pri.ee> - 2023-08-02 21:15 +0300
      Re: [OT] Help for a RegEx scott@slp53.sl.home (Scott Lurndal) - 2023-08-02 18:20 +0000
        Re: [OT] Help for a RegEx MarioCPPP <NoliMihiFrangereMentulam@libero.it> - 2023-08-03 00:56 +0200
      Re: [OT] Help for a RegEx MarioCPPP <NoliMihiFrangereMentulam@libero.it> - 2023-08-03 00:55 +0200
        Re: [OT] Help for a RegEx Paavo Helde <eesnimi@osa.pri.ee> - 2023-08-03 11:36 +0300
          Re: [OT] Help for a RegEx MarioCPPP <NoliMihiFrangereMentulam@libero.it> - 2023-08-04 02:01 +0200
            Re: [OT] Help for a RegEx Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-04 01:26 +0100
              Re: [OT] Help for a RegEx MarioCPPP <NoliMihiFrangereMentulam@libero.it> - 2023-08-05 02:17 +0200
                Re: [OT] Help for a RegEx jak <nospam@please.ty> - 2023-08-14 10:37 +0200
                  Re: [OT] Help for a RegEx MarioCCCP <NoliMihiFrangereMentulam@libero.it> - 2023-08-15 14:14 +0200
                    Re: [OT] Help for a RegEx jak <nospam@please.ty> - 2023-08-16 21:24 +0200
                      Re: [OT] Help for a RegEx MarioCCCP <NoliMihiFrangereMentulam@libero.it> - 2023-08-18 21:05 +0200
                        Re: [OT] Help for a RegEx jak <nospam@please.ty> - 2023-08-19 09:18 +0200
    Re: [OT] Help for a RegEx Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-08-02 11:58 -0700
    Re: [OT] Help for a RegEx wij <wyniijj5@gmail.com> - 2023-08-12 23:33 -0700

#91194 — [OT] Help for a RegEx

Sorry for the total OT, but I failed to build a RegEx with 
the "help" (rotfl) of three different so called IA, getting 
to nothing

I am scanning an HTML document (not in javascript, so I do 
not have access to DOM nodes from inside) and I need to 
match EVERY <p> whole tag.

for whole I mean, starting from the <p and ending with the 
corresponding </p>, but such paragrapha MAY (and may not) 
contain

a long list of attributes, with or without zero or more \n 
\r \t characters, valid, before the >.

An innerText possibly multiline, also with or without zero 
or more \n \r \t characters inside the text.

I have tried most suggestions from Bearly, ChatGpt and 
You.Com IA, but none worked

(my test is the RegEx engine from KATE Editor with the 
loaded HTML. It is handy since it highlights in yellow the 
matches, and I can verify that the RegEx tried fail to 
detect perfectly valid paragraphs).

If sb happens to be familiar with RegEx supporting 
"invisible" characters ... I'd be very grateful for any hint.
Ciao !

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#91195

Am 02.08.23 um 19:38 schrieb Fonntuggnio:
> 
> Sorry for the total OT, but I failed to build a RegEx with the "help" 
> (rotfl) of three different so called IA, getting to nothing
> 
> I am scanning an HTML document (not in javascript, so I do not have 
> access to DOM nodes from inside) and I need to match EVERY <p> whole tag.
> 
> for whole I mean, starting from the <p and ending with the corresponding 
> </p>, but such paragrapha MAY (and may not) contain

This may not be possible at all. RegExes cannot match nesting pairs, 
i.e. if your <p></p> contains other <p></p> pairs then you have reached 
the end of what a RE is capable of. Also due to the way these tags are 
structured, you need at least negative lookahead for it, which also not 
all RE engines support.

If you do
<p.*</p>

then the RE would catch from the first <p to the last </p>, hence you 
need to specify the .* with a lookahead like (?!</p>), or use a 
non-greedy RE.

> a long list of attributes, with or without zero or more \n \r \t 
> characters, valid, before the >.

> (my test is the RegEx engine from KATE Editor with the loaded HTML. 
> If sb happens to be familiar with RegEx supporting "invisible" 
> characters ... I'd be very grateful for any hint.

This may as well be the problem. Some RE engines treat newline 
characters as special, i.e. it may be that Kate matches only *within* a 
line.

In short - maybe a RE engine is simply not a good tool to do that. Then 
use an XML parser instead.

	Christian

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#91199

On 02/08/23 20:00, Christian Gollwitzer wrote:
> Am 02.08.23 um 19:38 schrieb Fonntuggnio:
>>
>> Sorry for the total OT, but I failed to build a RegEx with 
>> the "help" (rotfl) of three different so called IA, 
>> getting to nothing
>>
>> I am scanning an HTML document (not in javascript, so I do 
>> not have access to DOM nodes from inside) and I need to 
>> match EVERY <p> whole tag.
>>
>> for whole I mean, starting from the <p and ending with the 
>> corresponding </p>, but such paragrapha MAY (and may not) 
>> contain
> 
> This may not be possible at all. RegExes cannot match 
> nesting pairs, i.e. if your <p></p> contains other <p></p> 

this may be safely excluded. Other type of tags (like <i> or 
<em> may be nested, but not <p> itself). Is it still a problem ?

> pairs then you have reached the end of what a RE is capable 
> of. Also due to the way these tags are structured, you need 
> at least negative lookahead for it, which also not all RE 
> engines support.
> 
> If you do
> <p.*</p>
> 
> then the RE would catch from the first <p to the last </p>, 
> hence you need to specify the .* with a lookahead like 
> (?!</p>), or use a non-greedy RE.

the .* seem to fail facing multiline and tabs alas

> 
>> a long list of attributes, with or without zero or more \n 
>> \r \t characters, valid, before the >.
> 
>> (my test is the RegEx engine from KATE Editor with the 
>> loaded HTML. If sb happens to be familiar with RegEx 
>> supporting "invisible" characters ... I'd be very grateful 
>> for any hint.
> 
> This may as well be the problem. Some RE engines treat 
> newline characters as special, i.e. it may be that Kate 
> matches only *within* a line.

mmmmmm intresting.
What other editor would you recommend then ?

> 
> In short - maybe a RE engine is simply not a good tool to do 
> that. Then use an XML parser instead.
> 
>      Christian
> 

-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91196

02.08.2023 20:38 Fonntuggnio kirjutas:
> 
> Sorry for the total OT, but I failed to build a RegEx with the "help" 
> (rotfl) of three different so called IA, getting to nothing
> 
> I am scanning an HTML document (not in javascript, so I do not have 
> access to DOM nodes from inside) and I need to match EVERY <p> whole tag.
> 
> for whole I mean, starting from the <p and ending with the corresponding 
> </p>, but such paragrapha MAY (and may not) contain

I'm afraid HTML cannot be parsed with a regex in general. Also, the HTML 
rules are very lax, for example there is no such guarantee that there 
actually appears a corresponding terminating </p> tag.

Also, there is no guarantee that the actual content is contained in the 
<p> tags, it might well be outside and all the <p> tags might actually 
be empty <p/>.

For extracting the content of unknown pages reliably you would probably 
need some kind of a state machine, with a fair knowledge of obscure HTML 
rules. Of course, there are libraries for that.

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#91197

Paavo Helde <eesnimi@osa.pri.ee> writes:
>02.08.2023 20:38 Fonntuggnio kirjutas:
>> 
>> Sorry for the total OT, but I failed to build a RegEx with the "help" 
>> (rotfl) of three different so called IA, getting to nothing
>> 
>> I am scanning an HTML document (not in javascript, so I do not have 
>> access to DOM nodes from inside) and I need to match EVERY <p> whole tag.
>> 
>> for whole I mean, starting from the <p and ending with the corresponding 
>> </p>, but such paragrapha MAY (and may not) contain
>
>I'm afraid HTML cannot be parsed with a regex in general. Also, the HTML 
>rules are very lax, for example there is no such guarantee that there 
>actually appears a corresponding terminating </p> tag.
>
>Also, there is no guarantee that the actual content is contained in the 
><p> tags, it might well be outside and all the <p> tags might actually 
>be empty <p/>.
>
>For extracting the content of unknown pages reliably you would probably 
>need some kind of a state machine, with a fair knowledge of obscure HTML 
>rules. Of course, there are libraries for that.

Best way to deal with HTML is using xslt processors.  You may want
to run the html text through a canonicalizer first.

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#91201

On 02/08/23 20:20, Scott Lurndal wrote:
> Paavo Helde <eesnimi@osa.pri.ee> writes:
>> 02.08.2023 20:38 Fonntuggnio kirjutas:
>>>
>>> Sorry for the total OT, but I failed to build a RegEx with the "help"
>>> (rotfl) of three different so called IA, getting to nothing
>>>
>>> I am scanning an HTML document (not in javascript, so I do not have
>>> access to DOM nodes from inside) and I need to match EVERY <p> whole tag.
>>>
>>> for whole I mean, starting from the <p and ending with the corresponding
>>> </p>, but such paragrapha MAY (and may not) contain
>>
>> I'm afraid HTML cannot be parsed with a regex in general. Also, the HTML
>> rules are very lax, for example there is no such guarantee that there
>> actually appears a corresponding terminating </p> tag.
>>
>> Also, there is no guarantee that the actual content is contained in the
>> <p> tags, it might well be outside and all the <p> tags might actually
>> be empty <p/>.
>>
>> For extracting the content of unknown pages reliably you would probably
>> need some kind of a state machine, with a fair knowledge of obscure HTML
>> rules. Of course, there are libraries for that.
> 
> Best way to deal with HTML is using xslt processors.  You may want
> to run the html text through a canonicalizer first.

both terms were unknown to me beforehand, so I thank you 
since I can do some searches

> 

-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91200

On 02/08/23 20:15, Paavo Helde wrote:
> 02.08.2023 20:38 Fonntuggnio kirjutas:
>>
>> Sorry for the total OT, but I failed to build a RegEx with 
>> the "help" (rotfl) of three different so called IA, 
>> getting to nothing
>>
>> I am scanning an HTML document (not in javascript, so I do 
>> not have access to DOM nodes from inside) and I need to 
>> match EVERY <p> whole tag.

it is HTML generated by LibreOffice .odt, so rather well 
formatted (if not elegant)

>>
>> for whole I mean, starting from the <p and ending with the 
>> corresponding </p>, but such paragrapha MAY (and may not) 
>> contain
> 
> I'm afraid HTML cannot be parsed with a regex in general. 
> Also, the HTML rules are very lax, for example there is no 
> such guarantee that there actually appears a corresponding 
> terminating </p> tag.

I have read manually a lot of the generated code, and I had 
no evidence of bad formatting

> 
> Also, there is no guarantee that the actual content is 
> contained in the <p> tags, it might well be outside and all 
> the <p> tags might actually be empty <p/>.

true, <td> and some other contain some renderized text. But 
for my purpose just paragraphs could suffice.

> 
> For extracting the content of unknown pages 

they are not unknown : they are .odt exported as HTML, by 
LibreOffice.

> reliably you 
> would probably need some kind of a state machine, with a 
> fair knowledge of obscure HTML rules. Of course, there are 
> libraries for that.
> 

-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91202

03.08.2023 01:55 MarioCPPP kirjutas:
> On 02/08/23 20:15, Paavo Helde wrote:
>>
>> For extracting the content of unknown pages 
> 
> they are not unknown : they are .odt exported as HTML, by LibreOffice.

Well, that makes things easier. If we can exclude some complications 
like CDATA, HTML comments and nested <p> tags, then it might be indeed 
possible to use regex to extract some content.

Be sure to use a non-greedy regex to match the closest end tag </p>, and 
the equivalent of /s or dotall for '.' to match newlines (or use 
(.|\r|\n) instead of dot). This seems to work at first glance:

grep -Po '<p (.|\r|\n)*?</p>' abc.xhtml

(-P is needed for grep to support non-greedy search).

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#91204

On 03/08/23 10:36, Paavo Helde wrote:
> <p (.|\r|\n)*?</p>

intresting. I tried this one and it detects most of 
paragraphs, except those that does not have attributes 
within the <p> opening tag.

Is it there a way to also include those ones ?


-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91205

MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:

> On 03/08/23 10:36, Paavo Helde wrote:
>> <p (.|\r|\n)*?</p>
>
> intresting. I tried this one and it detects most of paragraphs, except
> those that does not have attributes within the <p> opening tag.
>
> Is it there a way to also include those ones ?

PH's regex insists on a space after the "<p".  Whilst this is not
exactly the same as requiring an attribute it will be effectively the
same.  You could try

  <p[ >](.|\r|\n)*?</p>

but I can't stress enough -- none of this can really work in all cases.

-- 
Ben.

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#91209

On 04/08/23 02:26, Ben Bacarisse wrote:
> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
> 
>> On 03/08/23 10:36, Paavo Helde wrote:
>>> <p (.|\r|\n)*?</p>
>>
>> intresting. I tried this one and it detects most of paragraphs, except
>> those that does not have attributes within the <p> opening tag.
>>
>> Is it there a way to also include those ones ?
> 
> PH's regex insists on a space after the "<p".  Whilst this is not
> exactly the same as requiring an attribute it will be effectively the
> same.  You could try
> 
>    <p[ >](.|\r|\n)*?</p>
> 
> but I can't stress enough -- none of this can really work in all cases.
> 

ok, tnx for the prudent disclaimer

Your variant found 3883 matches against 3644 matches found 
by the previous one.

scanning visually the book, it seems this RegEx is able to 
find ALL.

I'll try variants with h1...h10 to find headings also.

Many thanks for this precious hint

Now I try to better understand the Expression :D

-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91251

MarioCPPP ha scritto:
> On 04/08/23 02:26, Ben Bacarisse wrote:
>> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
>>
>>> On 03/08/23 10:36, Paavo Helde wrote:
>>>> <p (.|\r|\n)*?</p>
>>>
>>> intresting. I tried this one and it detects most of paragraphs, except
>>> those that does not have attributes within the <p> opening tag.
>>>
>>> Is it there a way to also include those ones ?
>>
>> PH's regex insists on a space after the "<p".  Whilst this is not
>> exactly the same as requiring an attribute it will be effectively the
>> same.  You could try
>>
>>    <p[ >](.|\r|\n)*?</p>
>>
>> but I can't stress enough -- none of this can really work in all cases.
>>
> 
> ok, tnx for the prudent disclaimer
> 
> Your variant found 3883 matches against 3644 matches found by the 
> previous one.
> 
> scanning visually the book, it seems this RegEx is able to find ALL.
> 
> I'll try variants with h1...h10 to find headings also.
> 
> Many thanks for this precious hint
> 
> Now I try to better understand the Expression :D
> 

Could I ask you if you could kindly provide a piece of text on which you
are doing the tests? Thanks in advance.

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#91255

On 14/08/23 10:37, jak wrote:
> MarioCPPP ha scritto:
>> On 04/08/23 02:26, Ben Bacarisse wrote:
>>> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
>>>
>>>> On 03/08/23 10:36, Paavo Helde wrote:
>>>>> <p (.|\r|\n)*?</p>
>>>>
>>>> intresting. I tried this one and it detects most of 
>>>> paragraphs, except
>>>> those that does not have attributes within the <p> 
>>>> opening tag.
>>>>
>>>> Is it there a way to also include those ones ?
>>>
>>> PH's regex insists on a space after the "<p".  Whilst 
>>> this is not
>>> exactly the same as requiring an attribute it will be 
>>> effectively the
>>> same.  You could try
>>>
>>>    <p[ >](.|\r|\n)*?</p>
>>>
>>> but I can't stress enough -- none of this can really work 
>>> in all cases.
>>>
>>
>> ok, tnx for the prudent disclaimer
>>
>> Your variant found 3883 matches against 3644 matches found 
>> by the previous one.
>>
>> scanning visually the book, it seems this RegEx is able to 
>> find ALL.
>>
>> I'll try variants with h1...h10 to find headings also.
>>
>> Many thanks for this precious hint
>>
>> Now I try to better understand the Expression :D
>>
> 
> Could I ask you if you could kindly provide a piece of text 
> on which you
> are doing the tests? Thanks in advance.
> 

well, actually not : it's an .ODF book converted to .HTML, 
written in LbO, with just a main structural index, headings 
untill Title3 rank, a few tables, and some 300'000 words of 
text. But, being unpublished and not going to be given away 
for free, I won't share the content.

The <p> tags are often heavily loaded with font style 
attributes, and some nested <span> tags, the text is also 
full of nested <i> and <b> tags (italics and bold). It's a 
very large document, but not complex in structure. Just 
badly designed (imvho).
For example LbO does not track smartly editings that could 
be "collapsed". It just dumbly obey and records formatting 
command as they are, It does not produce very "CLEAN" HTML. 
But I won't revise it manually, it's huge. And actually the 
books to be analyzed and steganized are SIX, not just one.

I have decised to use a true XML parser though, even if the 
RegEx worked well, the program is growing too complex to use 
string-only approeach, and I need some true "dom-like" aware 
approach to edit nodes content.

I am also considering to abandon GAMBAS and do that in 
Javascript, which is able to act upon the HTML from inside 
and injecting stuff is native at it.

Sorry if my reply is a bit frustrating, but those six books 
are 30 years of my life, I'heve poured blood in them :D





-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91270

MarioCCCP ha scritto:
> On 14/08/23 10:37, jak wrote:
>> MarioCPPP ha scritto:
>>> On 04/08/23 02:26, Ben Bacarisse wrote:
>>>> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
>>>>
>>>>> On 03/08/23 10:36, Paavo Helde wrote:
>>>>>> <p (.|\r|\n)*?</p>
>>>>>
>>>>> intresting. I tried this one and it detects most of paragraphs, except
>>>>> those that does not have attributes within the <p> opening tag.
>>>>>
>>>>> Is it there a way to also include those ones ?
>>>>
>>>> PH's regex insists on a space after the "<p".  Whilst this is not
>>>> exactly the same as requiring an attribute it will be effectively the
>>>> same.  You could try
>>>>
>>>>    <p[ >](.|\r|\n)*?</p>
>>>>
>>>> but I can't stress enough -- none of this can really work in all cases.
>>>>
>>>
>>> ok, tnx for the prudent disclaimer
>>>
>>> Your variant found 3883 matches against 3644 matches found by the 
>>> previous one.
>>>
>>> scanning visually the book, it seems this RegEx is able to find ALL.
>>>
>>> I'll try variants with h1...h10 to find headings also.
>>>
>>> Many thanks for this precious hint
>>>
>>> Now I try to better understand the Expression :D
>>>
>>
>> Could I ask you if you could kindly provide a piece of text on which you
>> are doing the tests? Thanks in advance.
>>
> 
> well, actually not : it's an .ODF book converted to .HTML, written in 
> LbO, with just a main structural index, headings untill Title3 rank, a 
> few tables, and some 300'000 words of text. But, being unpublished and 
> not going to be given away for free, I won't share the content.
> 
> The <p> tags are often heavily loaded with font style attributes, and 
> some nested <span> tags, the text is also full of nested <i> and <b> 
> tags (italics and bold). It's a very large document, but not complex in 
> structure. Just badly designed (imvho).
> For example LbO does not track smartly editings that could be 
> "collapsed". It just dumbly obey and records formatting command as they 
> are, It does not produce very "CLEAN" HTML. But I won't revise it 
> manually, it's huge. And actually the books to be analyzed and 
> steganized are SIX, not just one.
> 
> I have decised to use a true XML parser though, even if the RegEx worked 
> well, the program is growing too complex to use string-only approeach, 
> and I need some true "dom-like" aware approach to edit nodes content.
> 
> I am also considering to abandon GAMBAS and do that in Javascript, which 
> is able to act upon the HTML from inside and injecting stuff is native 
> at it.
> 
> Sorry if my reply is a bit frustrating, but those six books are 30 years 
> of my life, I'heve poured blood in them :D
> 
> 
> 
> 
> 

Hi Mario,
absolutely no problem. Maybe I misunderstood the thread and I thought
you refer to an XML document useful for debug. Practically a unique
document that contains all the characteristics, peculiarities and
exceptions of the XML that would allow an exhaustive debug of a parser.
If I had sensed that you refer to your personal document, then I would
not have allowed myself to make this request. Excuse me.

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#91301

On 16/08/23 21:24, jak wrote:
> MarioCCCP ha scritto:
>> On 14/08/23 10:37, jak wrote:
>>> MarioCPPP ha scritto:
>>>> On 04/08/23 02:26, Ben Bacarisse wrote:
>>>>> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
>>>>>
>>>>>> On 03/08/23 10:36, Paavo Helde wrote:
>>>>>>> <p (.|\r|\n)*?</p>
>>>>>>


> 
> Hi Mario,
> absolutely no problem. Maybe I misunderstood the thread and 
> I thought
> you refer to an XML document useful for debug. Practically a 
> unique
> document that contains all the characteristics, 
> peculiarities and
> exceptions of the XML that would allow an exhaustive debug 
> of a parser.
> If I had sensed that you refer to your personal document, 
> then I would
> not have allowed myself to make this request. Excuse me.
> 

don't even mention it ! My English is poor at times, I 
cannot explain very well :D

-- 
1) Resistere, resistere, resistere.
2) Se tutti pagano le tasse, le tasse le pagano tutti
MarioCPPP

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#91305

MarioCCCP ha scritto:
> On 16/08/23 21:24, jak wrote:
>> MarioCCCP ha scritto:
>>> On 14/08/23 10:37, jak wrote:
>>>> MarioCPPP ha scritto:
>>>>> On 04/08/23 02:26, Ben Bacarisse wrote:
>>>>>> MarioCPPP <NoliMihiFrangereMentulam@libero.it> writes:
>>>>>>
>>>>>>> On 03/08/23 10:36, Paavo Helde wrote:
>>>>>>>> <p (.|\r|\n)*?</p>
>>>>>>>
> 
> 
>>
>> Hi Mario,
>> absolutely no problem. Maybe I misunderstood the thread and I thought
>> you refer to an XML document useful for debug. Practically a unique
>> document that contains all the characteristics, peculiarities and
>> exceptions of the XML that would allow an exhaustive debug of a parser.
>> If I had sensed that you refer to your personal document, then I would
>> not have allowed myself to make this request. Excuse me.
>>
> 
> don't even mention it ! My English is poor at times, I cannot explain 
> very well :D
> 

Allora ce tocca da parlà come se magna XDD

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#91198

Fonntuggnio <JoeFonntuggnio@libbbero.it> writes:
> Sorry for the total OT, but I failed to build a RegEx with the "help"
> (rotfl) of three different so called IA, getting to nothing
>
> I am scanning an HTML document (not in javascript, so I do not have
> access to DOM nodes from inside) and I need to match EVERY <p> whole
> tag.
[...]

https://stackoverflow.com/a/1732454/827263

"TONY THE PONY HE COMES"

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

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#91250

On Thursday, August 3, 2023 at 1:39:17 AM UTC+8, Fonntuggnio wrote:
> Sorry for the total OT, but I failed to build a RegEx with 
> the "help" (rotfl) of three different so called IA, getting 
> to nothing 
> 
> I am scanning an HTML document (not in javascript, so I do 
> not have access to DOM nodes from inside) and I need to 
> match EVERY <p> whole tag. 
> 
> for whole I mean, starting from the <p and ending with the 
> corresponding </p>, but such paragrapha MAY (and may not) 
> contain 
> 
> a long list of attributes, with or without zero or more \n 
> \r \t characters, valid, before the >. 

The following is an example program of class Regex (class wrapper of regex(3)
functions). The regular expression "<p>.*</p>" should do most of the job, except
real HTML involves comments, nested tags, erroneous format...etc:

[]a_grep "<p>.*</p>" *html

-------------------------------------------------
/* Copyright is licensed by GNU LGPL, see file COPYING.       by I.J.Wang 2023

  Simulate grep command (Extended regular expression, ERE)

  Build: make a_grep
*/
#include <Wy.stdio.h>
#include <Wy.unistd.h>
#include <Wy.regex.h>

using namespace Wy;

constexpr const char Red[]="\x1B[31m";
constexpr const char Reset[]= "\x1B[0m";

void sim_grep(Regex& rexpr, const char* fname)
{
 Errno r;
 String str;
 ::regmatch_t mbuf[5];
 RegFile regf(fname,O_RDONLY);
 RdBuf strm(regf);

 for(;strm.is_eof()==false;) {
   if((r=strm.read(str))!=Ok) {
     WY_THROW(r);
   }
   if((r=rexpr.regexec(str.c_str(),mbuf,WY_CARR_SIZE(mbuf),0))!=Ok) {
     continue;
   }
   cout << fname << ": ";
   cout << StrSeg(str.begin(), str.begin()+mbuf[0].rm_so);
   cout << Red << StrSeg(str.begin()+mbuf[0].rm_so,
                         str.begin()+mbuf[0].rm_eo) << Reset;
   cout << StrSeg(str.begin()+mbuf[0].rm_eo, str.end());
 }
};

int main(int argc, const char* argv[])
try {
 static const char usage[]="a_grep <pattern> <file>+" WY_ENDL;
 Errno r;

 if(argc<3) {
   cout << "Error: Invalid argument" WY_ENDL "Usage: "
        << usage << WY_ENDL;
   return -1;
 }
 const char* ptn= argv[1];
 Regex rexpr;

 if((r=rexpr.regcomp(ptn,REG_EXTENDED))!=Ok) {
   if(r!=EBADMSG) {
     WY_THROW(r);
   }
   String str;
   if((r=rexpr.regerror(str))!=Ok) {
     WY_THROW(r);
   }
   cout << str << WY_ENDL;
   return -1;
 }

 for(int i=2; i<argc; ++i) {
   const char* fname= argv[i];
   sim_grep(rexpr,fname);
 }

 cout << "OK" WY_ENDL;
 return 0;
}
catch(const Errno& e) {
 cerr << wrd(e) << WY_ENDL;
 return -1;
}
catch(...) {
 cerr << "main() caught(...)" WY_ENDL;
 throw;
};

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