Retrival methods of ElementArray (and subclasses)

[gubaidulinvadim]

1. It seems that all Simulator/ControlSystem methods get_all_XXX, which I think are based on the ElementHolder class, returns a list and not arrays.
   A small example based on SOLEIL II example notebook:

control_mode = sr.design

bpms = control_mode.get_all_bpms() 
type(bpms) # returns list

bpms = control_mode.get_bpms("BPM")
type(bpms) # returns pyaml.arrays.bpm_array.BPMArray

From what I see, this is the case for all these methods, which prevent using the nice feature of the arrays.

2. The methods of the ElementHolder class have no docstrings, but they are the ones exposed to the user here.

control_mode.get_bpms?
Signature: control_mode.get_bpms(name: str) -> pyaml.arrays.bpm_array.BPMArray
Docstring: <no docstring>
File:      ~/Python_dev/pyaml/pyaml/pyaml/common/element_holder.py
Type:      method

3. More of a comment/question: maybe this is me not knowing how to use pyAML but I was thinking that string-matching was implemented at the array level, is it? I was expecting the following code to work:

bpms = control_mode.get_element("BPM*")
---------------------------------------------------------------------------
PyAMLException                            Traceback (most recent call last)
Cell In[74], line 1
----> 1 bpms = control_mode.get_element("BPM*")

File [~/Python_dev/pyaml/pyaml/pyaml/common/element_holder.py:109](http://localhost:8889/home/gamelina/Python_dev/pyaml/pyaml/pyaml/common/element_holder.py#line=108), in ElementHolder.get_element(self, name)
    108 def get_element(self, name: str) -> Element:
--> 109     return self.__get("Element", name, self.__ALL)

File [~/Python_dev/pyaml/pyaml/pyaml/common/element_holder.py:95](http://localhost:8889/home/gamelina/Python_dev/pyaml/pyaml/pyaml/common/element_holder.py#line=94), in ElementHolder.__get(self, what, name, array)
     93 def __get(self, what, name, array) -> Element:
     94     if name not in array:
---> 95         raise PyAMLException(f"{what} {name} not defined")
     96     return array[name]

PyAMLException: Element BPM* not defined

Originally posted by @GamelinAl in #195 (comment)

[JeanLucPons]

Yes get_all_* function returns list of Element and the wildcard selection works only on Arrays.
Arrays are named and are part of the holder in order to be accessible by name from tuning or measurement tools.

For the time being, you can create standalone arrays (no name, not added to a holder) like below

    ae = ElementArray("", sr.design.get_all_elements())
    bpms = ae["BPM*"]  # Returns a standalone BPM array (on design)

or

    allBpms = BPMArray("", sr.design.get_all_bpms())

We can propose convenience functions for standalone arrays:

  # Returns a standalone `BPMArray` without name and not added to the holder
  bpms = Arrays.get( sr.design, "BPM*") 
  bpms = Arrays.get( sr.design.get_all_bpms() )
  # or
  bpms = sr.design.get_arrays( "BPM*") 
  bpms = sr.design.get_all_bpm_array( )

or

We can change the interface of get_all_* function to return arrays with a default name, "all_bpms" or "all_magnets" for instance, and an optional argument for aggregators usage.

[GamelinAl]

@JeanLucPons if we agree that this is to be done at some point that's fine by me.
But as @gupichon-soleil was saying, maybe this part need a full restrucuration using the YellowPage concept of accml.
I think we can close this issue and start a discussion about it

[gupichon]

@GamelinAl, @JeanLucPons, I’m currently working on a proposal. I’ll open the discussion later today or tomorrow once I have a more consolidated architectural proposal.

[JeanLucPons]

The Catalog is linked to the control system.
Arrays have to work on both simulator and CS.
Catalog is already one more layer, I would like to minimize the number of layer.
But I'm waiting for proposal.

[gupichon]

It’s a completely different matter. The YellowPages are only about high-level PyAML objects for users and high-level tuning tools.

[JeanLucPons]

tuning tools and measurement tools have their names in the config.
I'm not sure to understand the idea of YellowPages ? You want one more indirection ?

I propose here a simple way to handle standalone arrays (without name) with only few modifications.

[gupichon]

Here we go:
Proposal: Runtime YellowPages for PyAML