I am using OpenIso8583.Net to generate my ISO messages and everything is perfect
except I am having troubles generating a message for a sub field.
I know I have to extend the AMessage class to achieve but clearly I am going about it all wrong.
Any simple example will help a lot. I would paste code but I am so far it's useless I am hoping this post makes sense to someone who has worked with sub fields on the ISO 8583 spec
http://code.google.com/p/openiso8583net/
above is the link to the library I am using
thanks
Related
I'm trying to port pydoctor to twisted.web.template and have hit a pretty basic problem: pydoctor uses epydoc to render docstrings into HTML but I can't see a way to include this HTML in the generated page without escaping. What can I do?
There is, somewhat intentionally, no way to insert HTML into the page without parsing; twisted.web.template is a bit more of a stickler about producing correct output than nevow was.
There are a couple of ways around this.
Ultimately, your HTML is going to some kind of output stream. You could simply insert a renderer that returns a pair of Deferred objects, and does a .write to the underlying stream after the first one fires but before the second. Kind of gross, but it effectively expresses your intent :).
You can simply re-parse the output of epydoc into HTML using XMLString or similar, so that twisted.web.template can write it out correctly. This will "waste" a little bit of CPU, but in my opinion it will be worth it for (A) the stress-test it will give t.w.t and (B) the guarantee - presuming that t.w.t is correct - that it will give you that you're emitting valid HTML.
As I was writing this answer, however, I realized that point 2 isn't generally possible with arbitrary HTML with the current public API of twisted.web.template. Ideally, you could use html5lib to parse this stuff, and then just dump the parsed input into your document tree.
If you don't mind mucking around with private API, you could probably hook up html5lib's SAX support to the internal SAX parser that we use to load templates.
Of course, the real solution is to fix the ticket you already filed, so you don't have to use private API outside of Twisted itself...
This should be a community wiki question.
I've had to work with a lot of vb.net lately, and recently created the following expression.
If If(report.IsPublicReport, False) Then Return True
Now, this is a simple coalesce inside of an if statement, nothing to be scared of. However, when I was scanning the method looking for an error I had made, this line would constantly stop me dead in my tracks. I just couldn't scan it. Every time I had to stop and break it down manually in my head. Largely because I had to stop and figure out what each If was actually doing in the expression.
I have since rewritten the line as
If report.IsPublicReport.GetValueOrDefault() Then Return True
While more verbose, I am finding that this disrupts my train of thought less as I am scanning the code.
This got me thinking,
Is this something other more experienced
VB.net developers are running into?
Are there any other types of
expressions that are largely
avoided, or at least not favored?
Am I just whining about nothing?
As long as you are uncomfortable with VB.NET syntax, I would strongly recommend you use Option Strict On so you catch mistakes like these quicker. The best way is by changing it globally so it is always on by default. Tools + Options, Projects and Solutions, VB Defaults, change Option Strict to "On".
What you're describing is something Scott Hanselman (and probably others) call "Code smell".
It's basically the idea that when you look at a piece of code and something doesn't seem "right" about it. This is not a capability that developers just "have". It's something you develop over time as you read and write more and more code.
It's not just VB either, you'll see plenty of idiomatic constructs in every language that will (or should) make you pause and question what you're looking at.
That Double IF would definitely do it for me
In Vb.NET you can write:
row!FirstName = "Test"
instead of
row("FirstName") = "Test"
A while ago I used to write row!FirstName (you can do that with every item in a collection that can be accessed by a string parameter) because I thought that was a good idea because it looks more statically typed (like person.FirstName as a property) and is shorter.
However I realized that this is not a good idea because after changing "FirstName" to "Name" i often looked for String in the current file which are highlited in Visual Studio (the object!param syntax is not).
Which makes finding them harder.
You can write
Private Sub Form1_Load() Handles MyBase.Load
End Sub
instead of
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
which is fine if you don't need sender or e (I suppose it is just some compiler magic that adds the signature itself) but I refuse to use the shorter way, cause you don't recognize it as an eventhandler at first sight.
I'm practicing OOP for 2 years (for real) and I know how to consume objects and packages and I'm developing stuffs mostly using C# .
but I have a problem with consuming unknown objects and packages as an instance :
for now I am working on an enterprise like website and for part of our job we need to consume RSS. I decided to use "System.Xml.Xpath"
and my real problem is:
for using system.xml.xpath I should look at manual and read it carefully and I don't want to do that every time.A plain example of that is like following code :
XPathDocument xp = new XPathDocument(sites[2]);
XPathNavigator nav = xp.CreateNavigator();
XPathNodeIterator it = nav.Select(xpath3);
foreach (XPathNavigator n in it)
{
//get elements here
}
//another way of iterating elements is
while(it.movenext())
{
//it.current.Value;
}
for the "foreeach" part I got it from MSDN manual and I guess I could get this simple fact by looking at class structure.
but I don't know which structure I should look.
I know how to read tooltips and I'm familiar with things like : [] / collection / enum /generic / Ienumerable / Idisposable etc...
but I think there is something about reading class behaviors and I'm missing that part.
for make it more lucid :
I know whenever we have a class that inherited from IEnumerable so we can use foreach statement against that class to iterate it through
my real problem is I think classes are self described enough to not to look at manuals all the time but I don't know how/where to read those descriptions of classes so I need your advice to get more familiar with how to reading classes without looking at manuals.
best regards.
Classes can (and should) be documented with source code comments, and in many languages you can generate API documentation from these comments (in HTML, XML or other format). In Java it is called Javadoc; I don't know the C# term. If this is what you call "manual", then this is your primary source of information. Other than reading the source code comments and the code itself (which you often don't have access to, especially in the MS universe). If you don't find enough information in the API documentation, you can always try googling for more explanation, tutorials or usage examples.
Hope this helps; I am not entirely sure I understood your question though. If this is not the answer you are looking for, please clarify.
Out of curiosity, what may the rationale behind these function names (found in Apple's Quartz Core framework) be?
ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv()
ZNK2CA6Render9Animation9next_timeEdRd()
ZN2CA11GenericRectIiE5insetEii()
Do you think the developers somehow encoded argument types in function names? How do you find yourself putting "EP19" in there in the course of day-to-day coding? In what circumstances do such barely readable function names actually help you read code and otherwise be more productive?
Thanks in advance for any hints, and Merry Christmas!
These 'mangled' names are automatically generated by the C++ compiler and indeed encode type information.
I've been mostly working with VB.Net for over a year and just noticed this
Am I going insane, or does VB.Net NOT have an "Unreachable code" warning?
The following compiles quite happily with nary a warning or error, even though there is a return between the two writeline calls.
Sub Main()
Console.WriteLine("Hello World")
Return
Console.WriteLine("Unreachable code, will never run")
End Sub
Am I missing something? Is there some way to switch this on that I can't find.
If not, is there a good reason for its omission? (i.e. or am I right in thinking this is a woeful state of affairs)
Forgive the air of rant about this question, it's not a rant, I would like an answer.
Thanks
I've raised this on MS Connect, as bug# 428529
Update
I received the following from the VB Teams program manager
Thanks for taking the time to report
this issue. The compiler has limited
support for this scenario, and as you
point out we don't have warnings for
unreachable code. There are some
scenarios that our flow analysis
algorithm does handle, such as the
following:
Sub Main()
Dim x As Integer
Return
x = 4
End Sub
In this case you'll get a warning that
x has never been assigned. For the
case you mentioned however we'll have
to look at implementing that for a
future release.
My guess is that it's an oversight in the compiler. Flow control is a very difficult problem to get correct in any language, but especially in a language like VB which has so many different flow control mechanisms. For instance,
Exceptions
Goto
On Error (Resume, Goto, etc ...)
Exit calls
If you feel strongly about this issue, please file a bug on Connect. We do take bugs filed via Connect very seriously and do our best to fix as many as possible.
They mention this in the following post:
https://stackoverflow.com/questions/210187/usage-statistics-c-versus-vb-net
See the last post.
I guess you could use FXCop to check your code instead or get a copy of Resharper from:
http://www.jetbrains.com/resharper/
I'd like to address Jared's answer.
Most of the issues he brings up are not problematic for data flow analysis.
The one exception is "On Error / Resume". They mess up data flow analysis pretty bad.
However, it's a pretty simple problem to mitigate:
If more than one "On Error" statement is used in a method, or the "Resume next" statement is used, you can just turn off data flow analysis and report a generic warning. A good one might be something like "On Error / Resume are deprecated, use exceptions instead." :)
In the common case of one only "On Error" statement and no "resume" statement, you can pretty much do normal data flow analysis, and should get reasonable results from it.
The big problem is with the way the existing DFA code is implemented. It doesn't use a control flow graph, and so changing it ends up being really expensive. I think if you want to address these kinds of issues you really need rip out the existing DFA code and replace it with something that uses a control flow graph.
AFAIK, you are correct that VB.NET does not give you a warning. C# does though.