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Re: XML module question?

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From:
David Warring
Date:
July 16, 2021 19:54
Subject:
Re: XML module question?
Message ID:
CABE6GaYLGBL15vTBqqXPyNFXuJkRSRGm1c_h8orPmT64WQSU4Q@mail.gmail.com
The XML::Writer <https://github.com/masak/xml-writer> module side-steps any
ordering issues by directly serializing data structures to xml:

$ raku -M XML::Writer -e'say XML::Writer.serialize: :wpt[ :lat<42>,
:long<69>, "blah" ]'
<wpt lat="42" long="69">blah</wpt>

On Sat, Jul 17, 2021 at 4:48 AM Bruce Gray <robertbrucegray3@gmail.com>
wrote:

> > On Jul 15, 2021, at 11:02 PM, William Michels via perl6-users <
> perl6-users@perl.org> wrote:
>
> (and I re-ordered):
>
> > Any help appreciated,
> > Thanks, Bill.
> > REFERENCE:  https://unix.stackexchange.com/q/166675/227738
>
>
> > I'm trying to put an answer together for SO, and I keep running into the
> same difficulty. Given a CSV file,
>
> Note: input is a log file, not in CSV format.
>
> > how can one produce an XML file with latitude and longitude values
> properly quoted? Every time I get proper quoting, "lat" and "lon" are
> scrambled (i.e. sometimes "lat" first, sometimes "lat" second).
> ...
> > using the "make-xml()" function from the XML module, I end up scrambling
> "lat/lon”:
>
> You are using the correct XML module, and you are using it correctly.
>
> Similar to a Raku hash, the attributes in an XML start-tag are *unordered*.
> While the inconsistant ordering may be displeasing to our human eyes, any
> program reading XML should treat your current output identically to your
> desired output.
>
> In Raku-speak, these two hashes have the same contents:
>     my %wpt1 = lat => 'A', lon => 'z';
>     my %wpt2 = lon => 'z', lat => 'A’;
>
> Designers of XML libraries are reluctant to add the ability to force an
> ordering; it would lead to XML-reading programs making improper assumptions.
> Like many major XML libraries in other languages, I see no such ability in
> the Raku XML module.
> See:
>         https://www.w3.org/TR/REC-xml/#sec-starttags
>                 Note that the order of attribute specifications
>                 in a start-tag or empty-element tag is not significant.
>
> https://stackoverflow.com/questions/57756005/writing-xml-attributes-and-namespace-declarations-in-a-specific-order
>
> https://community.adobe.com/t5/coldfusion/maintain-attribute-order-in-xml-with-a-structure/m-p/3838398
>
> > Conversely, if I manage to restrict "lat/lon" to the correct order, I
> lose the equals sign and proper (value) quotation.
>
>
> Unless you just hardcode a template and insert the lat/lon/datetime values
> (never a good idea), you will have to live with the varying order.
> I will point out that the XML library also does not output the multi-line
> indentation that the OP shows; it is irrelevant in XML.
>
>
> > $ raku -MXML -e 'my @xml = do for lines() {make-xml("wpt",
> :lat(.words[5].subst(";")), :lon(.words[8]), \("time",.words[0..2]))}; .put
> for @xml;’  lat_lon.txt
>
> Minor critiques:
> That use of `@array = do for lines() {…}` is more commonly written as
> `@array = lines().map: {…}`
>         raku -MXML -e 'my @xml = lines().map: {make-xml("wpt",
> :lat(.words[5].subst(";")), :lon(.words[8]), \("time",.words[0..2]))}; .put
> for @xml;'  lat_lon.txt
>
> Nothing is gained by creating an array, just to print each line of the
> array, so your can just `put` each time you construct an XML line.
>         raku -MXML -e 'for lines() { put make-xml("wpt",
> :lat(.words[5].subst(";")), :lon(.words[8]), \("time",.words[0..2])) }'
> lat_lon.txt
>
> When all the output is per-line based on the input, the `-p` or `-n` flag
> removes the need for `for lines`.
>         raku -MXML -ne 'put make-xml("wpt", :lat(.words[5].subst(";")),
> :lon(.words[8]), \("time",.words[0..2]))'  lat_lon.txt
>
>
>
> > So far, I can correctly swap the date/time to the end:
> >
> > $ raku -MXML -e 'my @reordered = do for lines()
> {(.words[3..*],.words[0..2])}; .put for @reordered;’  lat_lon.txt
>
> I am sure that `-MXML` is leftover from other experiments.
> Removing `@reordered` and switching to `-n` like my critiques above, this
> becomes:
>         raku -ne 'put (.words[3..*],.words[0..2]);' lat_lon.txt
> To “wow” the SO crowd, you might note that @array[N..*],@array[0..N-1] has
> a shortcut in Raku (.rotate), making this the tightest of all the solutions
> I see so far:
>         raku -ne 'put .words.rotate(3);'  lat_lon.txt
>
> --
> Hope this helps,
> Bruce Gray (Util of PerlMonks)
>
>

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