A proposed email to R-devel on connections

email.txt

Subject: Clarificaiton requested on 'connections' interface.


Hi All,

I am confused on the status of being able to create custom connections in R.

The functions 'R_new_custom_connection()' and 'R_GetConnection()' 
(defined in 'R_ext/Connections.h') are marked in 'sotools.c' as 'nonAPI'. 
This would seem to indicate that it is not for use in packages as it will 
cause a NOTE on CRAN.

However the manual 'Writing R Extensions' explicitly mentions using
"R_ext/Connections.h" for defining custom connections i.e. "Facilities 
for defining custom connection implementations are provided in 
R_ext/Connections.h, but make sure you consult the file before use."

Additionally 'R_GetConnection()' is mentioned in the R 3.3.0 NEWS as 
allowing "packages implementing connectionsto convert R connection objects 
to Rconnection handles"

In summary: 

1. Can "R_new_custom_connection()" and "R_GetConnection()" 
be used in packages?

2. If not, is there any other way for users to create custom connections?

3. If there is no current way to create custom connections, would
making this interface officially available be considered?

Thank you for your time,
Mike.

Given the timing, you may want to preface this by clarifying that you're asking for a specific package/project you've been developing, and not from an armchair perspective trying to stir up controversy (which would smell like you're trying to "trick" R-core members into contradictions – this is a bit how I interpreted the defensive response to Hadley's comments on some R-exts literal interpretation, that he was making bad-faith arguments (definitely not saying that he was, just that it seems to have been interpreted that way)).