From: Brad Ottoson <brad@...>
Date: 2008-02-17T03:34:59+09:00
Subject: Re: Code organization and modules

Thanks for the fix and the advice.  Using the self.getDeclaration fixed 
some problems.  I also realized I needed to have the module XTECpp 
declared somewhere and that fixed the rest of the errors.

Robert Klemme wrote:
> On 16.02.2008 08:48, Brad Ottoson wrote:
>> I'm working on an application for generating code skeletons from xml 
>> template files and have run into a snag.  I'm trying to organize a 
>> set of code in a directory and inside that use modules.  I have a set 
>> of files in a subdirectory of my project directory called lang_cpp.  
>> I'll paste in some code to show what I'm trying.
>>
>> --method_constructor.rb(in lang_cpp directory):
>>
>> module XTECpp::MethodConstructor
>>   def getDeclaration(codeClass)
>>     return "        " + codeClass.name + "();\n"
>>   end
>> end
>>
>> --method_destructor.rb(in lang_cpp directory):
>> module XTECpp::MethodDestructor        def getDeclaration(codeClass)
>>     return "        ~" + codeClass.name + "();\n"
>>   end
>> end
>>
>> Later in some other code I include the files using:
>> require 'lang_cpp/method_constructor.rb'
>> require 'lang_cpp/method_destructor.rb'
>>
>> which seems to work fine.  Later on I try the following:
>>           case funItem.name
>>             when "empty_constructor"
>>               headerString << 
>> XTECpp::MethodConstructor::getDeclaration(codeClass)
>>             when "empty_destructor"
>>               headerString << 
>> XTECpp::MethodDestructor::getDeclaration(codeClass)             when 
>> "operator_equality_assignment"
>>               headerString << 
>> XTECpp::MethodEqualityAssign::getDeclaration(codeClass)
>>             when "readugp"
>>               headerString << 
>> XTECpp::MethodReadUGP::getDeclaration(codeClass)
>>           end
>>
>>  and when I run it I get the error:
>>
>> C:\code\Ruby\XMLTemplateEngine\lib/lang_cpp/method_constructor.rb:5: 
>> uninitialized constant XTECpp (NameError)
>>         from C:\code\Ruby\XMLTemplateEngine\lib/lang_cpp.rb:6:in 
>> `require'
>>         from C:\code\Ruby\XMLTemplateEngine\lib/lang_cpp.rb:6
>>         from C:/code/Ruby/XMLTemplateEngine/lib/main.rb:6:in `require'
>>         from C:/code/Ruby/XMLTemplateEngine/lib/main.rb:6
>>
>> I tried changing the module names to the form 
>> XTECpp_MethodConstructor so each function was in it's own unique 
>> module but I got errors doing that too.  I'm not sure if you can ever 
>> do things this way in Ruby but I'd like to since this organization 
>> appeals to me.
>
> You want to use modules as namespaces but actually you define instance 
> methods in modules.  A small change will provide what you want:
>
> module XTECpp::MethodConstructor
>   def self.getDeclaration(codeClass)
>     return "        " + codeClass.name + "();\n"
>   end
> end
>
> A few other remarks: if you have just one method per module then the 
> idea with namespaces does not really make sense.
>
> You use camelCase for method names while in Ruby code this_style is 
> conventionally used.
>
> Your methods return leading whitespace which I assume serves to do 
> some indentation (and also a trailing linefeed).  I would not do that 
> but let the invoking code make sure indentation is properly - 
> otherwise you limit yourself to a single level of indentation.  Also 
> modularity of your code suffers because now your getXXX methods return 
> a piece of code *and* do indentation.
>
> Kind regards
>
>     robert
>
>
>