World: r3wp

Is it not enough to pass an html (string!) to load-html ?

yes, html string should be enough.

Script: {Allows "importing" modules at the console} (none)
Script: "Modules for REBOL 2" (none)
>> import %mezz/load-html.r

>> result: load-html "<p>This is a paragraph<p>This is another one"

== [root none [] [html [...] [] [head [...] [] [title [...] []]] 
[body [...] [] [p [...] [] [text [...] [value "This is a paragraph...

>> import %mezz/trees.r
>> print mold-tree result

[root [] [html [] [head [] [title []]] [body [] [p [] [text [value 
"This is a paragraph"]]] [p [] [text [value "This is another one"]]]]]]

Gabriele, thanks, it worked. I downloaded the build provided from 
above and it worked. Thank you.

modules were designed to help with building larger applications. 
i understand it can get in your way if you are doing something very 
small. You can still just DO the scripts but then you need to resolve 
the dependencies yourself, ie. do all the needed scripts in order. 
(there is a function inside tests/run.r that returns a block with 
all the modules a module depends on.)

In the following segment:


p [...] [id "myId" class "pclass"] [text [...] [value "Some text 
in the paragraph"]]

what does [...] represent?

Except "root" every html element is followed by this [...].

Is there a way to navigate this tree? Something similar to, let's 
say xslt path?

If I want to find a tag with a given ID, how is it done?

I'll try this: http://www.rebol.org/view-script.r?script=xpath.r

How do you eat your words on Altme?

hehehe

if you use MOLD-TREE, you won't see those [...]. they are back-references 
that are necessary internally. MOLD won't print them or it would 
be an infinite cycle.

you can navigate with GET-NODE, I haven't needed something like XSLT 
Paths yet (I had something closer to that in Temple).

root: load-html ...
p: get-node root/childs/html/childs/body/childs/p ; for eg.


most of the logic to do what you want is already in trees.r actually, 
because of the rewrite-tree function (that I don't use anymore). 
Anyway, a simple way would be:

get-node-with-id: func [root id] [
    if id = get-node root/prop/id [return root]
    foreach child get-node root/childs [
        if get-node-with-id child id [return child]
    ]
    none
]

(warning: not tested)

Thanks.

Hi Gabriele,


I'm trying out your power-mezz for the first time.  Do you have any 
other documentation on how to set it up properly?
Here is what I'm doing:


power-mezz-path:	to-path e:/Projects/PT/Rebol/power-mezz-built-1.0.0/
print "Starting mezz/module.r"
do power-module:	to-url ajoin [power-mezz-path 'mezz/module.r]
print	"Returned mezz/module.r"
load-module/from power-mezz-path
module [
	imports: [%mezz/html-to-text.r]
	]
--> e:/Projects/PT/Rebol/power-mezz-built-1.0.0/
--> Starting mezz/module.r

** Access Error: Invalid port spec: e:/Projects/PT/Rebol/power-mezz-built-1.0.0/mezz/module.r

** Near: do power-module: to-url ajoin [power-mezz-path 'mezz/module.r]

Any ideas on what I did wrong?

I've got a meeting to run to -- will check back in couple of hours 
 :-)

Here now, Anyone have ideas on how to use Power-Mezz for the beginner?

Also, what is the difference between power-mezz-1.0.0 and power-mezz-built-1.0.0?

Anyone have info on how to use Power-Mezz?

I installed it yesterday, it worked pretty well for what I needed.

do you need help on install or on what the actually mezz code does?

Hi Maxim,


I'm still learning Rebol, but I'd like to see how I can use Power-Mezz. 
 How do you install it?

Patrick, e:/Projects/... is not a valid rebol file path.

try with something like:


    power-mezz-path: %/E/Projects/PT/Rebol/power-mezz-built-1.0.0/
    do power-mezz-path/mezz/module.r
    load-modules/from power-mezz-path
    ; etc.

Oops -- Didn't see the malformed file path!!!

Where can I find  examples of how to use Power Mezz?

The particular script I am writing is called GET ADDRESS.  This script 
takes a CSV file called contacts which has first and last name, city 
and state of all of my friends that I'd like to get addresses for 
Christmas cards, but have forgotten or misplaced.


So far, the script takes each entry and sends it to SUPERPAGES.com 
where the HTML sent back contains the information.  Right now, I'm 
simply saving the HTML as a file for each entry in my CSV.


What I would like to do is somehow parse the HTML from it and extract 
out the address lines, zip code, phone number etc.  But I admit that 
parsing through HTML is daunting to me.  So after looking around 
on the internet, I discovered HTML-TO-TEXT in your Power Mezz.  


That is where I am now, trying to figure it out and see how it works. 
 I've read some of your documentation, but I admit, I am still in 
the dark as to how it works -- at least for my application.  Any 
advice you have is welcome.

Thanks in advance.

I don't think that's a good function to use for that. It seems to 
me it's meant for making readable text, not processable text

Use "5.10 Parse HTML text into a tree" instead

Thank you Kaj.  I'll check that out!

There's no usage documentation, though, only code documentation

There's also "7.4 [X][HT]ML Parser" so it's not clear to me which 
one is preferred

To be honest, if you just like to parse some HTML page to get some 
parts of it, you don't need to use Power Mezz at all.. I'm using 
Rebol more than 10 years and still consider PM as a too complex staff 
for me. If you are REBOL newbie, better to start reading REBOL doc. 
In your case something about parsing.

There is a lot of pages about 'parse' on net... for example this 
one: http://www.rebol.com/docs/core23/rebolcore-15.html

Thanks Oldes -- Will check into that

Yeah, there's some tipping point in parsing web pages and such. When 
the pages are consistent and the data you want to scrape is simple, 
I use PARSE, too, or even just string processing

But when the HTML and the data become more complex, there are so 
many exceptions you have to program, that a real HTML parser becomes 
more convenient

would a real HTML parser convert the data to a REBOL object?

hmm... not sure that is possible.

I don't know what the two PowerMezz ones do, but I figure they just 
produce blocks. It's static data, so no need for bindings

a good one would be to convert R3 rich text to HTML and vice versa.

but that is of course not related to parsing...

Yeah, I think someone will have to do that :-)

Kaj, I think it's the other way around! I found when the HTML and 
the data become more complex, then a simpler "hack" parse job is 
more likely to survive changes to the source. This happened to me 
several times with a weather forecast and television guide scraper 
etc. that I made (and remade, and remade..).

(back when I used to care about television, that is)

That's true when you have to write the parser yourself, but I'm assuming 
the PowerMezz parsers handle all of HTML :-)

Also, it's probably not as much within reach for novice programmers

I was using REBOL for datamining a few years ago and I can say it 
was easier to do string based parsing to get what I've needed.

It's always easier to do:  parse html [thru "<title>" copy title 
to "<"]  than parse complete html to something like a block structure 
and dig title in it.

For you, but my business partner wants to scrape web pages, and I 
don't think he would understand how to do it with parse

I believe that if he would not understand simple parse, than he would 
not understand PowerMezz as well, but maybe I'm wrong. Also it very 
depends what page do you parse.

Scraping a title is the simplest example. In reality, you get all 
sorts of tags with extra attributes that you need to skip, and values 
with extraneous newlines. He wouldn't understand how to normalise 
that, so his data would be left as a mess