Create Symbol should have editable drop down list with default reference designations

[Seth Hillbrand]

When creating a symbol, I sometimes forget which reference designator is usually used for varistor (RV) and which for variable resistor (VR) or what to use for a directional coupler or delay line.

It would be nice to have a drop-down list of common ones so I don't have to go back to look up the oddballs. It would still be type-in for those who want their own.

Application: kicad
Version: (6.0.0-rc1-dev-729-g1b37f93cf), release build
Libraries:
    wxWidgets 3.0.2
Platform: Linux 4.9.0-8-amd64 x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.2 (wchar_t,wx containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.62.0
    OpenCASCADE Community Edition: 6.8.0
    Compiler: GCC 6.3.0 with C++ ABI 1010

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=OFF
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON

[Jeff Young (jeyjey)]

https://www.ee.iitb.ac.in/~spilab/Tips/ansii_graphic_symbols_for_electrical_and_electronics_daigrams_1993.pdf, starting on page 213.

Although for this purpose, I think https://en.wikipedia.org/wiki/Reference_designator#cite_note-IEEE-315-1975-2 is probably good enough.

[Ian McInerney (imcinerney)]

@Seth, this seems like it is opening a can of worms... specifically what reference designator list should we use? There is the IEEE one that Jeff linked, but it appears that the KiCad library doesn't follow that itself and deviates in some instances (see [1], [2], [3]).

[1] https://github.com/KiCad/kicad-symbols/issues/939
[2] https://github.com/KiCad/kicad-doc/issues/655
[3] https://github.com/KiCad/kicad-symbols/issues/808

[Seth Hillbrand (sethh)]

As a card-carrying IEEE member, I'm biased. :)

I don't think we need to account for all library uses currently, we just pick a standard and set it as the default going forward. This doesn't prevent other uses, just nudges us into the same use for future symbols.

[KiCad Janitor (kicad-janitor)]

KiCad bug tracker has moved to Gitlab. This report is now available here: https://gitlab.com/kicad/code/kicad/-/issues/2257