Re: [pygccxml-development] Additional attribute functionality

[Ben S. <bsc...@lu...>]

Um, ok I finally saw this page. having a link to it inside the
documentation would be useful..
I think that the use of exceptions in this context is overkill,
considering that exceptions should only be used in "exceptional" cases.
I think that java suffered from the same problem of overuse of
exceptions.
=20
However, I think I'll stick to mem_fun*s(..., allow_empty=3Dtrue) for =
now.
It makes more sense...
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Cheers
Ben
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PS. I don't understand how we are avoiding a loop by writing
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for decl in class_.decls():
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wouldn't this be the same if decls() returned a list?
And then the benefit of a list would be it's standard operations...
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________________________________

	From: Roman Yakovenko [mailto:rom...@gm...]=20
	Sent: Tuesday, December 04, 2007 12:29 PM
	To: Ben Schleimer
	Cc: pyg...@li...
	Subject: Re: [pygccxml-development] Additional attribute
functionality
=09
=09
	On Dec 4, 2007 9:58 PM, Ben Schleimer <bsc...@lu...>
wrote:
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		Hi Roman,
		   Another thing to keep in mind for after 1.0 is that
the scopedef is very difficult to work with.
		When I write class_.member_function("foobar"), I expect
either a value or None to be returned. I don't expect an exception to be
thrown
		likewise, I'd like to see
class_.member_functions("foobar") to return a list of declarations, zero
if no declaration matches. Again, no exception should be through.
		Then I can take the list and manipulate it like a normal
python list.
	=09


	Did you read this
http://language-binding.net/pygccxml/query_interface.html document? The
behavior you are talking about was implemented intentionally.=20
=09

	I prefer to think about "mem_fun" as "get" function, which
should raise in error if there is 0 or 2+ member functions with the same
name. The behavior you propose doesn't distinct between these cases. On
the other side raised exception contains enough information to explain
what went wrong.=20
=09
	I think about "mem_fun*s*" as a query function, it can return
zero or more items that match search criteria. You can customize the
behavior of this function. By default it raises an exception if no match
was found. Pass "allow_empty=3DTrue" as function argument to disable
exception if no match was found. I understand that not everyone agrees
with such behavior, so scopedef_t.ALLOW_EMPTY_MDECL_WRAPPER variable was
introduced. You can set it to False, after this "mem_fun*s*"  method
will not raise exception on "no match".=20
=09
	Now, the return value of the "mem_fun*s*" method is very
carefully constructed class that allows the user to avoid writing of
loops.
	Link to the class
http://language-binding.net/pygccxml/apidocs/pygccxml.declarations.mdecl
_wrapper.mdecl_wrapper_t-class.html
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	The class implements "container" interface and in general you
should not notice the difference between it and the list class.=20
=09
	I am using pygccxml for code generation projects. May be you are
right and the interface is really "less than intuitive", but it is very
valuable for code generation projects maintenance. If the underlying
code change, class was removed, renamed or moved, you get immediately
very helpful error message.=20
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	Does it make sense now?
=09
	P.S. Of course "mem_fun*s*" is just an example and every
"query/select" function has same behavior.
=09
	--=20
	Roman Yakovenko
	C++ Python language binding
	http://www.language-binding.net/=20