IOC: Convert an IOC to Lua

[John-Holt-Tessella]

As a developer I want an IOC converted to use LUA because it is a nicer language to use to start an IOC.

Acceptance criteria

1. IOC st.cmd uses LUA instead
2. Database is still updated
3. Devsim and rec sim tests still run in the IOC test framework
4. Log is still captured as log file and in the database
5. Errors in missing macros, db files are still reported

[Alistair-McGann-Tessella]

I started writing a lua boot script as part of another ticket; I had to stop because it was getting too much work. The issue I came across was that asynSetOption was not available to be called from lua.

The remedy to this is adding asynSetOption to the lasynlib.cpp file in core lua. There are other asyn functions already called from this file which can be used as templates.

We also need to find a place for generally useful lua scripts. We decided these would go in the utilities repository so they can be accessed everywhere. I wrote a few functions which are generally useful to all IOC boot files; I didn't get as far as moving them out of a single lua script though.

The lua script I wrote is on this branch:
https://github.com/ISISComputingGroup/EPICS-ioc/tree/Ticket4288_sample_lua_code

[JamesKingWork]

ISISComputingGroup/EPICS-lua#2
ISISComputingGroup/EPICS-ioc#433
ISISComputingGroup/EPICS-utilities#12

[JamesKingWork]

A lua script is now called from st-common.cmd to run the regular functionality of st-common.cmd

Lua utility scripts now placed in utilities module and used in the st-common.lua

IocTestFramework tests for oercone pass. However, the code can definitely be cleaned up and not all acceptance criteria are met.

Still to do:

• Launch lua version of st.cmd from cpp main function and do functionality of st.cmd in lua
• Clean up dead code
• Test against hardware

[JamesKingWork]

See new ticket for future work on this issue #4811