World: r3wp

Now has anyone written a recursive routine to turn a rebol object 
into XML?  I couldn't find anything like this on rebol.org yet it 
doesn't sound hard to do ...

There must be something, but I don't have anything here that turned 
up, and I don't remember doing one myself. If it helps, you could 
use the JSON converter in %json.r as a starting point.

This seems to work for me ...

obj2xml: func [ obj [object!] out [string!]
	/local o 
][
	foreach element next first obj [
		repend out [ to-tag element newline ]
		either object? o: get in obj element [
			obj2xml o out
		][
			repend out [ o newline ]
		]		
		repend out [ to-tag join "/" element newline ]
	]
]

using this 

obj2xml: func [ obj [object!] out [string!]
	/local o 
][
	foreach element next first obj [
		repend out [ to-tag element newline ]
		either object? o: get in obj element [
			obj2xml o out
		][
			repend out [ o newline ]
		]		
		repend out [ to-tag join "/" element newline ]
	]
]

crap ... clipboard bug

>> probe obj
make object! [
    a: "testing"
    b: "again"
    c: make object! [
        d: "testing2"
        e: "again2"
        f: make object! [
            g: "testing3"
            h: "again3"
        ]
    ]
    i: "finished"
]

gives this 

<a>
    testing
</a>
<b>
    again
</b>
<c>
    <d>
        testing2
    </d>
    <e>
        again2
    </e>
    <f>
        <g>
            testing3
        </g>
        <h>
            again3
        </h>
    </f>
</c>
<i>
    finished
</i>

Hmm..
Really, have you the tabulations ?

Yes, separate script does the tabulations

probably should change line 
repend out [ o newline ]
to 
repend out [ any [ o copy "" ] newline ]

then, for NONE! values, it will  add an empty line

format-xml: func [ xml
    /local out space prev
][
    out: copy ""
    spacer: copy ""
    prev: copy </tag>
    foreach tag load/markup xml [
        either tag = find tag "/" [
            ; we have a close tag
            

            ; reduce the spacer by a tab unless the previous was an open tag
            either not tag? prev [
                ; not a tag
                remove/part spacer 4
            ][
                ; is a tag
                if prev = find prev "/" [
                    ; last was a closing tag
                    remove/part spacer 4
                ]
            ]
        ][ 
            either tag? tag [
                ; current is tag
                ; indent only if the prev is not a closing tag
                if not prev = find prev "/" [
                    insert/dup spacer " " 4
                ]
            ][
                ; is data
                insert/dup spacer " " 4 
            ]
        ]
        repend out rejoin [ spacer tag newline ]
        prev: copy tag
    ]
	view layout compose [ area (out) 400x400 ]
]

obj2xml: func [ obj [object!] out [string!]
	/local o 
][
	foreach element next first obj [
		repend out [ to-tag element ]
		either object? o: get in obj element [
			obj2xml o out
		][
			repend out any [ o copy "" ]
		]		
		repend out [ to-tag join "/" element ]
	]
]

remove the newlines to solve that issue :)

I was using rebelxml to construct xml ... but I came across some 
bugs.  So this way of doing it looks easier ....

What are people using to construct large XML documents ... of 100s 
of lines?

a modified version of John's rebXML  tools.  changed the output structure 
to allow rebol's path notation to be used to traverse the loaded 
xml.

I also replaced the use of url for the tag words because they fail 
when using namespaced xml elements.

building output objects instead would be simple, but the RAM/Speed/symbol 
table implications of all the binding involved makes this un-optimal.

(...objects instead of  blocks ....)

So, you used blocks instead of objects?

yes all the time.  accessing is exactly the same as for objects. 
 its actually much more flexible.

cause you have have the same element severall times, which is valid 
xml, but invalid in contexts.

True

and you can easily separate attributes from elements, just by affecting 
them to different types.

Although the XML I'm dealing with doesn't have duplicate elements.

Or name spaces

Have you posted your modifications anywhere??

the most stable engine I built which accepted all xml possibilities 
ended loading xml like so:


[ <element> [<subelement> [#attribute  "attr-value" . "subelement 
content"]]]

the .  is assigned the value of the elements. 

the above would result from the following XML:
<element>
	<subelement attribute="attr-value">
		subelement content
	</subelement>
</element>

And you can access it this way:

document/<element>/<subelement>/#attribute
document/<element>/<subelement>/.

I find working with objects much easier though ...

I guess the duplicate elements could be solved by using blocks for 
them

I've never posted that specific version cause it was closed source 
for a client.   but I have my own new engine, which does the same, 
but attacking the parse rules directly... its probably faster.
I've not released it.

Really? I went positional: ["element" "namespace" ["attribute" "value"] 
["subelement" ...] "text" ...]

with missing namespace or attribute block being #[none], so defaults 
can be done with ANY.

Using tags looks ugly :)

note that in the above, you can replace types within so it could 
be words instead of tags.

My positional version handles multiple subelements of the same type, 
and using strings rather than words lets you use tags that don't 
match word syntax or are case=sensitive.

its just that in my tests, either you can create, read or set some 
of the datatypes via path notation.  so only string based types allow 
full XML qualification.

hahaha

XML can be case sensitive??

but brian, how do you acess it?

by position!

XML *is* case-sensitive. Your paths can't access multiple subelements 
of the same type, or embedded text.

I wrote a simple xpath compiler too (but don't know where it is now).

I wanted direct access to all elements within rebol.

Looks like we need an article on best practices here ...

a later version, using schema validation, understands multiple subelements 
and automatically converts them to blocks IIRC.

so you do document/element/3/subelement/#attribute.

Your paths can't access multiple subelements of the same type, or 
embedded text. It might have worked for that customer but not the 
general case. No namespace support either.

my paths.. namespace works... for sure.  did you know you can have 
colon in word names in R2 !   but i didn;t use that, I just used 
tags directly.  more obvious than strings, and the exact same effort 
and speed.

I was parsing xhtml and other XML of the like. Subelements of mixed 
types in order with text between them than mattered.