static function is not found in RLangPApplet instance in renjin

[gaocegege]

Update summary:

renjin does not currently offer core support for accessing static methods/fields via an instance (bedatadriven/renjin#320). The workaround (e.g. in #134) was to map static functions from RLangApplet in core.R (https://github.com/gaocegege/Processing.R/blob/master/src/rprocessing/r/core.R#L187) -- however if renjin adds core support for static access in the future this could be dropped.

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radians is a function in PApplet, I am not sure why it raises an error with #95

Instance of class rprocessing.RLangPApplet has no member named 'radians'

It fails examples/Basics/Trigonometry

[gaocegege]

I have found the cause, we will meet the problem when radians, ceil and so on is called.

It seems that renjin couldn't handle the static function well. processing$radians(...) works, but

radians = processing$radians
radians(...)

will return Instance of class rprocessing.RLangPApplet has no member named 'radians'

And

import(rprocessing.RLangPApplet)
radians = RLangPApplet$radians
radians(...)

works well.

[gaocegege]

ref bedatadriven/renjin#320

We could wait the renjin to fix the problem

[jeremydouglass]

Good investigation, and a clear bug report to renjin.

They have been very responsive and supportive so far. Let's see what effort level it would take for renjin to add static variable support, and what kind of priority they can make it.

[gaocegege]

Thank 😄

We have two options, actually:

1. Wait until there is a PR to fix the problem, or file a PR to renjin and fix the problem on our own. Then we could wrap these static functions by xxx = processing$xxx
2. Use xxx = RLangPApplet$xxx instead

And I think we could put the issue to low priority since there is only one function used in the examples. If the issue will be there for a long time, then we could use the latter way to avoid it.