On Monday, 25 February 2013 at 20:09:14 UTC, Lars T. Kyllingstad
wrote:
Exceptions are designed to handle exceptional cases. A missing
environment variable isn't exceptional, it is commonplace.
I disagree. I don't know your uses cases, but as far as I can
see, if the program expects the variable to be present in the
environment, then it is no different from a missing file which
the program expects to be present, or malformed user input.
That would depend on the application.
Could you provide a specific example? It's difficult to discuss
the merits of either approach without some use cases.
As I see, there are two major cases:
1) The program expects a variable to be set. An example of this
is COMSPEC / SHELL. These variables ought to be set on any
system, so the user is not expected to verify this himself. The
variables not being set is an exceptional sitation.
2) A variable may or may not be set, such as the case of passing
additional options via the environment (such as INCLUDE, or
LD_PRELOAD). The program will take specific action if the
variable is not set, such as pretending it is empty, or
defaulting to some other setting like one in a configuration file.
It seems like your approach caters to the second situation
exclusively. I've mentioned the problems of applying this
approach to the first situation in my previous post.
