2.4. Spacing
You'l l
notice in examples throughout this book that we indent elements and
add spaces wherever it helps make the code more readable to humans.
Doing so is not unreasonable if you ever have to edit or inspect XML
code personally. Sometimes, however, this indentation can result in
space that you don't want in your final product.
Since XML has a make-no-assumptions policy toward your data, it may
seem that you're stuck with all that space.
One solution is to make the XML processor smarter. Certain parsers
can decide whether to pass space along to the processing
application.[6] They can determine
from the element declarations in the DTD when space is only there for
readability and is not part of the content. Alternatively, you can
instruct your processor to specialize in a particular markup language
and train it to treat some elements differently with respect to
space.
When neither option applies to your problem, XML provides a way to
let a document tell the processor when space needs to be preserved.
The reserved attribute xml:space can be used in
any element to specify whether space should be kept as is or
removed.[7]
For example:
<address-label xml:space='preserve'>246 Marshmellow Ave.
Slumberville, MA
02149</address-label>
In this case, the characters used to break lines in the address are
retained for all future processing. The other setting for
xml:space is
"default," which means that the XML
processor has to decide what to do with extra space.
 |  |  | 2.3. Namespaces |  | 2.5. Entities |
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