Cobra Forums

Posted: **Wed Feb 23, 2011 3:17 pm**

I have a class which is Serializable and has a XmlAttributeAttribute [XmlAttribute(AttributeName = "no")]

C# code

Code: Select all: using System; using System.Collections.Generic; using System.Xml.Serialization; namespace TVRage.Model { [Serializable] public class Season { [XmlAttribute(AttributeName = "no")] // This is how to do it in C# :) public int Number { get; set; } [XmlElement("episode")] public List<Episode> Episodes { get; set; } } [Serializable, XmlRoot("episode")] public class Episode { [XmlElement("epnum")] public int Number { get; set; } [XmlElement("seasonnum")] public int SeasonNumber { get; set; } [XmlElement("airdate")] public DateTime Airdate { get; set; } [XmlElement("title")] public string Title { get; set; } } }

Cobra code

use System.Xml
use System.Xml.Linq
use System.Xml.Serialization

namespace Broadcatcher.Models

    class Season has Serializable
        
        pro number from var as int = 0
            has XmlAttribute(AttributeName='no') # the problem is here
            
        pro episodes from var as List<of Episode> = List<of Episode>()
            has XmlElement('episode')

    class Episode has Serializable, XmlRoot("episode")
    
        pro number from var as int = 0
            has XmlElement('epnum')
            
        pro seasonNumber from var as int = 0
            has XmlElement('seasonnum')
            
        pro airdate from var as DateTime
            has XmlElement('airdate')
            
        pro title from var as String?
            has XmlElement('title'))

When I try compiling the above cobra code (on .net and mono), I get the following error:

Code: Select all: error: Local variables must start with a lowercase letter. This avoids collisions with other identifiers such as classes and enums.

Environments:

Code: Select all: Windows 7 64 bit - .net 4.0 - cobra 0.8.0 post-release Mac OS X 10.6.6 - Mono JIT compiler version 2.10 (tarball Mon Feb 14 16:04:48 MST 2011) - 0.8.0 post-release

The C# version works on both.

Any ideas? I hope it is just a silly syntax error on my end.

Posted: **Wed Feb 23, 2011 6:15 pm**

1) Property names in Cobra start with lowercase in Cobra so change line 10:

# from:
            has XmlAttribute(AttributeName='no') # the problem is here
# to:
            has XmlAttribute(attributeName='no') # the problem is here
#                            ^

The error message was misleading and needs fixing. I'll look into it.

2)
Next error is the extra right paren on the last line. Easy.

3)
Next error is back at line 10 again. It says that XmlAttribute has no property called "attributeName" which certainly seems true when I look at the docs:
http://msdn.microsoft.com/en-us/library/system.xml.xmlattribute.aspx

Btw those classes don't seem to inherit the Attribute class which seems odd. Also, declaration attributes in both C# and Cobra typically leave out the "Attribute" part of the name. And I think "XmlAttribute" is just using the word "attribute" for things like the "href" in <a href="foo">, not for the .NET declaration kind. It's an overloaded term.

Let me know if you have further questions or problems.

Posted: **Thu Feb 24, 2011 4:29 am**

I suspect the error from 3) is a cobra lookup bug.

It should be (as an attribute lookup) searching for and finding System.Xml.Serialization.XmlAttributeAttribute
(i.e an Attribute subclass or something named <cobraNameAsGiven>Attribute) - instead its hitting on System.Xml.XmlAttribute (first) which is not an Attribute or subclass and then reporting the mismatch.

Possibly a pretty obscure occurrence since there's not that much collision between class names and Attribute (sub) classes.

Posted: **Thu Feb 24, 2011 4:48 am**

Explicitly setting the namespace of the attribute like this

Code: Select all: pro number from var as int = 0 has System.Xml.Serialization.XmlAttribute(attributeName='no')

unexpectedly gives this confusing diagnostic

Code: Select all: # cobc0 xmlattr.cobra xmlattr.cobra(10): error: Cannot find a definition for "XmlAttributeAttribute or XmlAttribute" in "Serialization" whose type is "Serialization". There is a member named ".XmlAttributeAttribute" with a similar name. Compilation failed - 1 error, 0 warnings

which I'd hazard a guess to indicate a lookup against System.Xml.Serialization.XmlAttribute but not a probe for System.Xml.Serialization.XmlAttributeAttribute if the first lookup fails.

However this does compile

Code: Select all: pro number from var as int = 0 has System.Xml.Serialization.XmlAttributeAttribute(attributeName='no')

Posted: **Thu Feb 24, 2011 5:50 am**

Thanks guys!
@hopscc, it indeed compiles and runs

Posted: **Thu Feb 24, 2011 10:02 pm**

We'll see if we can get that cleaned up soon so that non-attribute classes are skipped in the search. Thanks for sharing this with us.

Posted: **Fri Feb 25, 2011 2:03 am**

(chuck) Make a ticket for it with any pertinent info if you dont want to or wont get to it directly .

Posted: **Sat Feb 26, 2011 2:50 pm**

The problem where "XmlAttribute" is bound to the wrong class is now fixed.

Posted: **Sat Feb 26, 2011 3:25 pm**

Random tip inspired by the original posted code:

# You can write this:
    pro episodes from var as List<of Episode> = List<of Episode>()
# as this:
    pro episodes from var = List<of Episode>()

# You would use the first form if you wanted the property to have a more general type than the initial value:
    pro episodes from var as IList<of Episode> = List<of Episode>()

# That's IList vs. List above in case it doesn't stand out.

Posted: **Sat Feb 26, 2011 7:59 pm**

I fixed the problem with the poor error message when the attribute property name was capitalized.

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