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Ross Bamford wrote:
> Hi,
>
> I've today committed changesets including Mark Van Holstyn's patches, an
> additional patch I received from Tim Yamin, and a few small fixups and
> extra tests. These fix bugs in XML::Node#content, and add several
> convenience methods to Node and Node::Set as previously discussed, as well
> as defining node equality based on the XML representation.
does this mean? node1 === node2
>
> I am now considering implementing callback procs for the SAX parser, and
> would appreciate any ideas anyone might have. Currently I'm looking at two
> choices:
>
> 1) Having methods for each callback supported by libxml, which
> work like set_trace_func:
>
> saxparser.set_begin_document(lambda { |...| })
> saxparser.set_begin_element(lambda { |...| })
> # ...
I seem to be a fan of the on_* naming convention for callbacks, since the
terminology "on" itself seems to show that somethng will
happen. And I like just passing blocks.
saxparser.on_begin_document { |doc| ... }
# callback for all elements
saxparser.on_begin_element { |node| ... }
# callback for only the elements which are "mynode"s
saxparser.on_begin_element( "mynode" ) { |mynode| ... }
>
> 2) Introducing a new class (maybe XML::SaxParser::Callbacks?)
> that provides the above API, and then having e.g.:
>
> saxparser.set_callbacks(the_callbacks)
>
> This could also have an alternate API, e.g:
>
> the_callbacks[:begin_document] = lambda { |...| }
> the_callbacks[:begin_element] = lambda { |...| }
I think the above api adjustment will get rid of this need. With the above api
I think it is more readable to. Even if you have a
long callback method
begin_element_proc = lambda{ |node|
# a few lines long
# a few lines long
# few lines long
# etc... }
saxparser.on_begin_element { |node| being_element_proc.call node }
Seems more readable then:
begin_element_proc = lambda{ |node|
# a few lines long
# a few lines long
# few lines long
# etc... }
# ... somewhere else in code
hsh ||= {}
hsh[ :begin_element ] = begin_element_proc
#... somewhere else in code
saxparser.set_callbacks hsh
To me it apperas more readable because you see what on_begin_element is doing
upfront, rather then having to find the declaration
of the data structure you use when you pass it into 'set_callbacks', and then
tracking down where you actually assign the
lambda/proc to your data structure.
just my 2 cents
Zach
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