Generics in C# look inferior to templates (especially to concepts) in C++,
however now and then you can build a wonderful pieces the way a C++ profi would
Consider a generic converter method:
T Convert<T>(object value).
In C++ I would create several template specializations for all supported
conversions. Well, to make things harder, think of converter provider supporting
public interface IConverterProvider
Converter<object, T> Get<T>();
That begins to be a puzzle in C++, but C# handles it easily!
My first C#'s implementation was too naive, and spent too many cycles in
provider, resolving which converter to use. So, I went on, and have created a
sofisticated implementation like this:
private IConverterProvider provider = ...
public T Convert<T>(object value)
var converter = provider.Get<T>();
public class ConverterProvider: IConverterProvider
public Converter<object, T> Get<T>()
private static class Impl<T>
// Heavy implementation initializing converters.
converter = ...
public static readonly Converter<object, T> converter;
Go, and do something close in C++!
Living in Israel, moving almost exclusively in a car I would not experience
what I've seen today in metro of Paris.
On the Ranelagh station an old woman has entered the train. She's in her mid
seventies. Once, she was beautiful. She still is! Colors and features are faded
but her dressing and posture are still elegant. But what's struck me most are
her eyes. Well, they ain't beautiful anymore. I've read a sadness there.
I think she will probably live ten or even twenty years more, but she would give them up just for one year to be younger.
If you have a string variable
$value as xs:string, and want to know whether it starts from a digit, then what's the best way to do it in the xpath?
Our answer is:
($value ge '0') and ($value lt ':').
Looks a little funny (and disturbing).
In our project we're generating a lot of xml files, which are subjects of manual
changes, and repeated generations (often with slightly different generation
options). This way a life flow of such an xml can be described as following:
- generate original xml (version 1)
- manual changes (version 2)
- next generation (version 3)
- manual changes integrated into the new generation (version 4)
If it were a regular text files we could use
diff utility to prepare
patch between versions 1 and 2, and apply it with
patch utility to
a version 3. Unfortunately xml has additional semantics compared to a plain text. What's an
invariant or a simple modification in xml is often a drastic change in text.
patch does not work well for us. We need xml diff
The first guess is to google it! Not so simple.
We have failed to find a tool or an API that can be used from ant. There are a
lot of GUIs to show xml differences and to perform manual merge, or doing
similar but different things to what we need
(like MS's xmldiffpatch).
Please point us to such a program!
Meantime, we need to proceed. We don't believe that such a tool can be
done on the knees, as it's a heuristical and mathematical at the same time
task requiring a careful design and good statistics for the use cases. Our idea
is to exploit
patch. To achieve the goals we're going to
perform some normalization of xmls before
diff to remove redundant
invariants, and normalization after the
patch to return it into a readable form.
- ordering attributes by their names;
- replacing unsignificant whitespaces with line breaks;
- entering line breaks after element names and before attributes, after
attribute name and before it's value, and after an attribute value.
This way we expect to recieve files reacting to modifications similarly to text
Ladies and gentlemen of the jury, exhibit number one is what the seraphs, the misinformed, simple, noble-winged seraphs, envied. Look at this the most ancient program:
At present C# serializer knows how to print comments and do some formatting (we had to create micro xml serializer within xslt to serialize xml comments). C#'s formatting is not as advanced as java's one, but it should not be such in the first place, as C# text tends to be more neat due to properties and events. Compare:
instance.Items.Value = value;
TODO: implement API existing in jxom and missing in C# xom. This includes:
- name normalization - rewriting tree to make names unique (duplicate names are often appear during generation from code templates);
- namespaces normalization - rewriting tree to elevate type namespaces (during generation, types are usually fully qualified);
- unreachable code detection - optional feature (in java it's required, as unreachable code is an error, while in C# it's only a warning);
- compile time expression evaluation - optional feature used in code optimization and in reachability checks;
- state machine refactoring - not sure, as C# has
yield statement that does the similar thing.
Update can be found at: jxom/C# xom.
June, 24 update: name and namespace normalizations are implemented.
Writing a language serializer is an as easy task, as riding a bicycle. Once you learned it, you won't apply a mental force anymore to create a new one.
This still requires essential mechanical efforts to write and test things.
Well, this is the first draft of the C# xslt serializer. Archive contains both C# xom and jxom.
Note: no comments are still supported; nothing is done to format code except line wrapping.
Today an old book was extracted by my son on the light of God. The book was immediatly opened on this verse:
Any trifle can become
a main business of your life.
You just need be a firmly believed
that there is nothing more important that can be achieved.
And then nothing won't prevent you gasp out from delight to engage with this nonsense.
Unfortunatelly too often these facetious verses of Gregory Oster becoming a true.
I've read a popular scientific stuff about DNA, RNA, proteins, cells,
prokaryotes and eukaryotes their structures, roles, operational principles,
All the computer technologies and robotics seem like a childish babbling
comparing to microbiology and molecular biology.
I would wish to be so open minded, and have so capable brain with infinite work
capacity (and live so long life ) to push, to break through the borders of knowledge of the humanity.
Ah, I envy to the Renaissance people who were capble to hold and drive the
science and art, this contrasts so much with contemporary specializations.
Well, it's jxom no more but also csharpxom!
A project concerns demanded us to create a C# 3.0 xml schema.
Shortly we expect to create an xslt serializing an xml document in this schema into a text. Thankfully to the original design we can reuse java streamer almost without changes.
A fact: C# schema more than twice bigger than the java's.
Today, I've found a C++0x FAQ by Bjarne Stroustrup reviewing most of the new features that we shall see in the next version.
A good insight for those who don't track the WG progress.
But what attracts me is a passage:
Sounds rather pessimistic to my taste.
There is a nice
ServiceLoader API in java 6 implementing a service provider idiom. It's good
(good because it's standard) class resolving interface implementation using
Unfortunately, there is even no JSR implementation for this class in java 5. This
makes it impossible for us to use it.
What a nuisance!
We honour the memory of our grandfathers and grandmothers who battled that
cruel war. Our grandfather has fallen in that war, other grandfather and grandmothers have survived and
lived long lives.
Time is relentless, they have left this world but we shall keep them and
their deeds in memory.
Yesterday, we've found an article
"Repackaging Saxon". It's about a decision to go away from Saxon-B/Saxon-SA
packaging to a more conventional product line: Home/Professional/Enterprise
The good news are that the Saxon stays open source. That's most important as an
open comunity spirit will be preserved. On the other hand Professional and
Enterprise Editions will not be free.
In this regard the most interesting comments are:
John Cowan> I suspect that providing packaging only for $$ (or pounds or euros) won't actually work, because someone else will step in and provide that packaging for free, as the licensing permits.
Michael Kay> This will be interesting to see. I'm relying partly on the idea that there's a fair degree of trust, and expectation of support, associated with Saxonica's reputation, and that the people who are risking their business on the product might be hesitant to rely on third parties, who won't necessarily be prompt in issuing maintenance releases etc; at the same time, such third parties may serve the needs of the hobbyists who are the real market for the open source version.
Michael Kay> ...I haven't been able to make a model based on paid services plus free software work for me. It's hard enough to get the services business; when you do get it, it's hard to get enough revenue from it to fund the time spent on developing and supporting the software. Personally, I think the culture of free software has gone too far, and it is now leading to a lack of investment in new software...