[REBOL] Re: generating XML ?

From: joel:neely:fedex at: 15-Jun-2002 8:15

Hi, Jason,

Jason Cunliffe wrote:
> I need to generate XML from REBOL...
>

Do you mean from arbitrary REBOL block structures, or from block
similar in structure to the output of PARSE-XML?

If the latter, here is some work-in-progress that might be of
interest:

8<--------------------------------------------------
xml-lib: make object! [

    q1: to-char 39 ; single quote
    q2: to-char 34 ; double quote

    _xentities: reduce [
        "&" "&amp;"
        "<" "<"
        ">" ">"
        q2  "&quot;"
    ]

    _xescape: func [s [string!] /local r] [
        r: copy s
        foreach [chr ent] _xentities [replace/all r chr ent]
        r
    ]

    _xenquote: func [s [string!] /local q] [
        rejoin [
            q: either find s q2 [
                either find s q1 [ s: _xescape s q2 ][ q1 ]
            ][
                q2
            ]
            s q
        ]
    ]

    _xformattrs: func [a [block! none!] /local r] [
        r: copy ""
        foreach [name value] any [a []] [
            repend r [" " name {=} _xenquote value]
        ]
        r
    ]

    _xform: func [b [block!] pre [string!] /local r c d] [
        r: copy ""
        append r rejoin [pre "<" first b _xformattrs second b]
        either none? c: third b [
            append r rejoin [" />" newline]
        ][
            append r ">"
            either all [
                1 = length? c
                string? d: first c
                60 >= length? d
		newline <> last d
            ][
                append r rejoin [
                    _xescape d "</" first b ">"
                    newline
                ]
            ][
                append r newline
                foreach item c [
                    append r either string? item [
                        rejoin [item newline]
                    ][
                        _xform item join "    " pre
                    ]
                ]
                append r rejoin [pre "</" first b ">" newline]
            ]
        ]
        r
    ]

    xform: func [b [block!]] [
        _xform either word? first b [first third b] [b] ""
    ]

    xtrim: func [b [block!] /local b3 b31] [
        if found? b3: third b [
            while [not empty? b3] [
                either string? b31: first b3 [
                    either empty? trim/head/tail b31 [
		    	remove b3
		    ][
		    	b3: next b3
		    ]
                ][
                    xtrim b31
                    b3: next b3
                ]
            ]
            if empty? head b3 [
                b/3: none
            ]
        ]
        b
    ]

]
8<--------------------------------------------------

XML-LIB/XTRIM removes the ignorable whitespace from the content
of an XML-derived block structure, as in this case:

    >> foo: {
    {    <drill model="DB-375">
    {    <motor rating="0.25h" />
    {    <chuck size="0.375" />
    {    <description>
    {    A wonderful Father's Day gift idea!  On sale now!
    {    </description>
    {    <price wholesale="27.45" retail="49.95" />
    {    </drill>
    {    }
    == {
    <drill model="DB-375">
    <motor rating="0.25h" />
    <chuck size="0.375" />
    <description>
    A wonderful Father's Day gift idea!  On s...

    >> bletch: parse-xml foo

after which BLETCH has the following structure (reformatted for
email):

    [document none [
        ["drill" ["model" "DB-375"] [
            "^/"
            ["motor" ["rating" "0.25h"] none]
            "^/"
            ["chuck" ["size" "0.375"] none]
            "^/"
            ["description" none [
                {^/A wonderful Father's Day gift idea!  On sale now!^/}
            ]]
            "^/"
            ["price" ["wholesale" "27.45" "retail" "49.95"] none]
            "^/"
        ]]
    ]]

where the extra newlines (for example) are not relevant to the "data-
oriented" content.  We can say

    xml-lib/xtrim bletch

to tidy up the content of BLETCH as follows:

    [document none [
        ["drill" ["model" "DB-375"] [
            ["motor" ["rating" "0.25h"] none]
            ["chuck" ["size" "0.375"] none]
            ["description" none [
                "A wonderful Father's Day gift idea!  On sale now!"
            ]]
            ["price" ["wholesale" "27.45" "retail" "49.95"] none]
        ]]
    ]]

Since this is still in the canonical XML-as-blocks form, we can say

    >> print xml-lib/xform bletch
    <drill model="DB-375">
        <motor rating="0.25h" />
        <chuck size="0.375" />
        <description>A wonderful Father's Day gift idea!  On sale
 now!</description>
        <price wholesale="27.45" retail="49.95" />
    </drill>

(note that the description wrapped, the max length is tweakable).

OTOH, we can start with a block structure of the same scheme:

    glorp: [
        "computer"
        ["owner" "dilbert"]
        [   [
                "cpu"
                ["model" "athlon" "speed" "4.5GHz"]
                []
            ]
            [
                "ram"
                ["type" "ddr" "size" "4096Mb"]
                []
            ]
            [
                "disk"
                ["size" "512Gb" "speed" "10500rpm"]
                ["just for home use"]
            ]
        ]
    ]

which can be rendered in XML by

    >> print xml-lib/xform glorp
    <computer owner="dilbert">
        <cpu model="athlon" speed="4.5GHz">
        </cpu>
        <ram type="ddr" size="4096Mb">
        </ram>
        <disk size="512Gb" speed="10500rpm">just for home use</disk>
    </computer>

HTH!

-jn-

--
; Joel Neely                             joeldotneelyatfedexdotcom
REBOL [] do [ do func [s] [ foreach [a b] s [prin b] ] sort/skip
do function [s] [t] [ t: "" foreach [a b] s [repend t [b a]] t ] {
| e s m!zauafBpcvekexEohthjJakwLrngohOqrlryRnsctdtiub} 2 ]

1 · 2 · 3 · [4] · See whole thread