[erlang-questions] Newbie question: avoiding massive 'case' statement

David Mitchell monch1962@REDACTED
Wed Mar 5 21:59:05 CET 2008

Hello everyone,

Newbie alert...

I've got a block of code that looks like:

case TransactionType of
  "ZABC" ->
  "Z123" ->
  "YPQX" ->
  TransactionType ->
    error_logger:info_msg("Unknown transaction type")

This is all fine and dandy, but I'm expecting the 'case' statement to
grow to handle several hundred different values of TransactionType
over time.  The code is going to get unwieldy in size, and the
likelihood of mistakes in cut/paste updating of the 'case' block is
going to get pretty high.

As an alternative to the above, is there a way to do something like

  error_logger:info_msg("Unknown transaction type")

where &&&TransactionType&&&:process_request(...) is some "magic code"
that lets me call the process_request function in the module that has
the name of the value of TransactionType  (hopefully that's clear, if
not necessarily English)?

Alternately, is there some sort of refactoring I could do to avoid the
massive 'case' statement?

There may be some obvious solution to do this, but I haven't been able
to find it...

Thanks in advance

Dave Mitchell

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