R devel - Apr 2023 - Unique ID for conditions to supress/rethrow selected conditions?

On Sun, 16 Apr 2023 at 12:58, nospam at altfeld-im.de <nospam at
altfeld-im.de> wrote:
>
> I am the author of the *tryCatchLog* package and want to
>
> - suppress selected conditions (warnings and messages)
> - rethrow  selected conditions (e.g a specific warning as a message or to
"rename" the condition text).
>
> I could not find any reliable unique identifier for each possible condition
>
> - that (base) R throws
> - that 3rd-party packages can throw (out of scope here).
>
> Is there any reliable way to identify each possible condition of base R?
I don't think so. As stated in the manual, "?simpleError? is the class
used by ?stop? and all internal error signals".
> Are there plans to implement such an identifier ("errno")?
I agree that something like this would be a nice addition. With the
current condition system, it would be certainly easy (but quite a lot
of work) to define a hierarchy of built-in conditions, and then use
them consistently throughout base R. For example,
> 1 + "a"
Error in 1 + "a" : non-numeric argument to binary operator

could be a "typeError". And catching this is already possible:
> e <- errorCondition("non-numeric argument to binary operator",
class="typeError")
> tryCatch(stop(e), typeError=function(e) print("hello"))
[1] "hello"

-- 
I?aki ?car

On Sun, 2023-04-16 at 13:52 +0200, I?aki Ucar wrote:
> I agree that something like this would be a nice addition. With the
> current condition system, it would be certainly easy (but quite a lot
> of work) to define a hierarchy of built-in conditions, and then use
> them consistently throughout base R.
Yes, a typed condition system would be great.

I have two other ideas:



By reading the "R messages" and "preparing translactions"
sections of the "R extensions manual"

https://cran.r-project.org/doc/manuals/r-release/R-exts.html#R-messages

I was thinking about using the "unique" R message texts (which are the
msgid in the *.po files,
see e.g.
https://github.com/r-devel/r-svn/blob/60a4db2171835067999e96fd2751b6b42c6a6ebc/src/library/base/po/de.po#L892)
to maintain a unique ID (not dependent on the actual translation into the
current language).

A "simple" solution could be to pre- or postfix each message text with
an ID, for example this code here

     else errorcall(call, _("non-numeric argument to function"));
     #
https://github.com/r-devel/r-svn/blob/49597237842697595755415cf9147da26c8d1088/src/main/complex.c#L347

would become

     else errorcall(call, _("non-numeric argument to function [47]"));
or
     else errorcall(call, _("[47] non-numeric argument to function"));

Now the ID could be extracted more easily (at least for base R condition
messages)...

This would even be back-portable to older R versions to make condition IDs
broadly available "in the wild".



Another way to introduce an ID for each condition in base R would be ("the
hard way")

1) by refactoring each and every code location with an embedded message string
to use a centralized
   key/msg_text data structure to "look up" the appropriate message
text and

2) use the key to enrich the condition as unique ID (e.g. as an attribute in the
condition object).