Error/exception fallbacks

[nyurik]

Is there an "fallback in case of an error or exception" function in Miller? Something similar to Excel's iferror (as oppose to iserror).

Usage patterns:

iferror( <something that MAY result in an error>,  <value to use in case of an error>)

Alternative - exception-like syntax (probably too verbose here?)

try:
  <something that crashes>
except:
  do in case of an error

P.S. I searched for a while in the docs, but all "error" searches link to is_error function, which is not as convenient to use.

[johnkerl]

@nyurik really this needs #1106 ... from very long ago (2015), when I was starting Miller, I wanted a single bad data cell to not crash processing entirely. The intention was good, but the execution -- in many places, cell values get the MT_ERROR datatype, which is distinct from MT_INT or MT_STRING etc, and which renders as (only) (error). What that implementation did was to hide any useful information about what that error cause might have been. #1106 is about doing a better job of surfacing that.

Here ... hmm, I think the iferror (which is a splendid idea!!) is actually orthogonal to #1106 (which is a big project). And would be quick and easy to code up, and, I think intuitive and easy for users to reason about.