in reply to Re^4: Should Modules Do I/O?
in thread Should Modules Do I/O?

As you acknowledge, these three interfaces can be implemented using eachother.

I did not acknowledge that--I flat out contradicted it.

Neither of the other two interfaces can be easily wrapped to provide each other, nor that which I described.

And I'm not sure how you came to that reading from my post?

Nobody is suggesting that the OP should make one and only one interface available, except you (unless I am misunderstanding your position).

You are not misunderstanding my position. I think that a single flexible interface is prefereable to multiple overlapping interfaces. Adding bloat to a module is detrimental rather than value-add IMO.

If there are common usage scenarios that would benefit from a simpler interface, these should be provided through a separate package that wraps the flexible interface in the same way that LWP::Simple wrap LWP::Useragent and XML::Simple wraps either XML::Parser or XML::SAX.

I'm not into deeply nested hierachies, but two levels strikes a good balance between depth and breadth at all levels.

  • It allows the segregation of the code for both maintenance and use.
  • It allows the *::Simple documentation to be exactly that, rather than mixing it up with the complexities of the full interface.
  • The *::Simple module becomes an excellent "API design" test, and long-term regression test for the primary module.
  • It also serves as a "worked example" of both using the primary module and extending it.
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    Lingua non convalesco, consenesco et abolesco.
    Rule 1 has a caveat! -- Who broke the cabal?

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    Re^6: Should Modules Do I/O?
    by Mugatu (Monk) on Mar 18, 2005 at 22:17 UTC
      As you acknowledge, these three interfaces can be implemented using eachother.
      I did not acknowledge that--I flat out contradicted it ... And I'm not sure how you came to that reading from my post?

      I was talking about this sentence:

      With the interface I describe, the other two interfaces can be trivially derived through subclassing, or just simple procedural wrappers.

      What you call trivially derived is what I meant when I said implemented using eachother. Just to make it even more clear, I meant you can make the filehandle interface, and have the other interfaces use that.

      If there are common usage scenarios that would benefit from a simpler interface, these should be provided through a separate package that wraps the flexible interface

      This is six of one or half dozen of the other. If you insist on moving the simple interfaces into a ::Simple module, so be it. But it should be made from the beginning, otherwise there will be users who end up writing code they shouldn't have to write.

      Frankly, I think that the more good interfaces there are available, the better. It can be done cleanly, and it can be done without "adding bloat to a module." Your position on this matter flies in the face of my years of experience using Perl.

      PS: I will not reply any further. I have said about all I can on this subject. Please feel free to respond, but don't expect me to.

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