Re: RPGle - i wish i could do some 'Reflection'

[Jon Paris <jon.paris@xxxxxxxxxxxxxx>]

While not reflection in the purist sense, it is possible to write your own interface to achieve some of what you want.

First the called program has to have been compiled with the option PGMINFO(*PCML: *MODULE). Once that is done then PCML is stored in the module object that describes the parameters, program name etc. That can be used directly by the JT400 toolkit for Java calls. You can also retrieve it programatically with the API QBNRPII.

Since PCML does not support all possible parameter types etc. it is not a complete solution but it is not something the RPG team can do anything about without help from the OS and the JT400 team. 

Similar situation with Operational Descriptors - RPG can only use what the system supports - and that needs to be extended.

 
On 2013-10-30, at 10:21 AM, Charles MARTIN <cmartin@xxxxxxxxxxxxxxx> wrote:

> Hello everyone,
>
> I wish i could do some reflection using RPGLe.
> By reflection, I mean :
> 'The process or mechanism of determining the capabilities of an object at run-time.'
>
> Imagine you have this datastructure :
>
>     D DS_Format       DS                  Qualified Based(pDS_Format)
>     D  Type                         20I 0 Inz(1)
>     D  Label                        50A   Inz('myLabel')
>     D  Description                5000A   Inz('myDescription')        
>
> With a reflection api, I could do this :
> 	Reflection_ListSubfields(DS_Format);
> => return this array : { 'Type', 'Label', 'Description' }
> And then, I could do :
> 	Reflection_GetSubfield(DS_Format : 'Label');
> => return 'myLabel'
>
> I wish i could do this too :
> 	Reflection_GetSubfieldType(DS_Format : 'Label');
> => return 'A'
> 	Reflection_GetSubfieldLength(DS_Format : 'Label');
> => return 50
> 	Reflection_GetSubfieldPrecision(DS_Format : 'Type');
> => return 0
>
>
> With this, I expect I could do something like this (with some little work) :
> 	SerializeXml(DS_Format); //I build xml with one line of code !
> And get :
> 	<DS_Format>
> 		<Type>1</Type>
> 		<Label>myLabel</Label>
> 		<Description>myDescription</Description>
> 	</DS_Format>
> And conversely with DeserializeXml(myXml);
>
> Reflection would help me to build really cool apis.
> Is there any way ?
>
> Charles
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Jon Paris

www.partner400.com
www.SystemiDeveloper.com