| Re: Embedded methods in objects [message #2139 is a reply to message #2128] |
Mon, 11 February 2019 15:58  |
christian.rahmig
Messages: 436
Registered: January 2016
|
Senior Member |
|
|
Dear Claus,
Am 04.02.2019 um 19:27 schrieb Claus Feyling:
> [...] We suggest that a new element called ‘formula’ is added to every object
> in railML. The cardinality is 0..*, but just one such element will be
> relevant for each attribute within the object. Deleting the object from
> a model will also delete its formulas. The immediate purpose of such an
> element is to allow standardisation of a versatile data structure based
> on railML, where the object’s behaviours are modelled along with their
> static values. In this way, a railML model may be loaded into a host
> system and then modified partly by entering new data values directly in
> the object’s attributes, partly by letting the objects calculate their
> own values.
thank you very much for your ideas and input! The approach sounds
interesting.
> Formulas are associated with attributes, using the mandatory attribute
> ‘name’.
>
> The railML writing system decides whether to store attribute values
> only, or attribute values as well as their formulas.
>
> We suggest that the open source scripting language Lua is defined as the
> default scripting language within railML.
>
> We suggest that the default evaluation depth is 1, see more about this
> below.
>
> The purpose of including such definitions in railML is to allow a railML
> writing system to store a model with formulas that can later be picked
> up and used or further refined by another railML reading system.
>
> As an example, the ‘code’ attribute of a switch may be associated with a
> formula as follows in order to receive a computed value based on its
> ‘seq’ attribute:
> <formula name=”code” encoding=”lua” depth=”1”>
> if dir == ‘up’ then
> return 500 + (2*seq+1)
> elseif dir == ‘down’ then
> return 500 + (2*seq+0)
> end
> </formula>
To be honest, I have not heard of such "formulas" before and
consequently my know-how is very limited in this field. But how about
the other railML users with export and import interfaces? Do you
consider formulas as essential keystone for the railML standard and do
you have experiences with "Lua" or similar approaches?
Any feedback is highly appreciated...
Best regards
Christian
--
Christian Rahmig - Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Phone Coordinator: +49 173 2714509; railML.org: +49 351 47582911
Altplauen 19h; 01187 Dresden; Germany www.railml.org
Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org
|
|
|
|
Members
Search
Help
Login
Home
