Or method enhancements #4

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1. brudgers commented on Aug 13, 2013

   

   brudgers

   on Aug 13, 2013

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   The right implementation of or is ambiguous.

   Should it be capable of implementation like this?

   (verbal-Expression-0
   (or
   (Verbal-Expression-1)
   (Verbal-Expression-2)
   (Verbal-Expression-3) )
   Verbal-Expression-4)

   Or must it be implemented like this?

   (Verbal-Expression-0)
   (or)
   (Verbal-Expression-1))

   The first requires or to accept at least two arguments.

   If or accepts no arguments then it has to be the second form. That's the
   way of the original implementation.

   I went around this with the Racket implementation which currently is a
   macro that does the second but with further work could implement the first.

   Ben

   On Tue, Aug 13, 2013 at 7:12 AM, Patrice Ferlet notifications@github.comwrote:

   Still working on implementatin, I see the whole implementation (excepting
   mine, but I'm wrong to implement this before speaking about with you) uses
   this kind of method:

   or(value)
   => ...|value

   I'm afraid that this one is not very usefull. It can be ok for simple
   test, but what about finding:

   startofline, then "foo", then "bar", endofline
   OR
   startofline, then "bar", then "baz". endofline

   My implementation does:

   StartOfLine().Then("foo").Then("bar").EndOfLine().Or().StartOfLine().Then("bar").Then("baz").EndOfLine()

   That returns:

   (?m)(?:^(?:foo)(?:bar)$)|(?: ^(?:bar)(?:baz)$)

   I only records an array of "parts" to concatanate at compile time... My
   unittest work as expected.

   —
   Reply to this email directly or view it on GitHubhttps://github.com//issues/4
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2. metal3d commented on Aug 16, 2013

   

   metal3d

   on Aug 16, 2013

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   Sorry for the late answer, I was out for 2 days.
   You're right, my implementation is not fully effective.

   With my implementation, this tests:

   A.(B+C)
   

   should be call with distributed form:

   (A+B) . (A+C)
   

   "A" is evaluated 2 times if B is false

   I like your idea but I dislike the fact to have "var args" (optionnal argument) (certainly because I develop with Go :))

   I have got another idea that is (I guess) more effective. I think that Or() method should get a VerbalExpression object as argument. And with should add a method named "And()" that accept VerbalExpression object.

   This is an example:

   v1 = new VE().Find("B")
   v2 = new VE().Find("C").Or(v1); // (B+C)
   v = new VE().Find("A").And(v2) // A.(B+C)
   

   This should return:

   (?m)(?:A)(?:(?:B)|(?:C))
   

   This way, we can imaginate very complexe expressions that are seperated in several objects... I can prepare a branch to validate if that works
3. metal3d commented on Aug 16, 2013

   

   metal3d

   on Aug 16, 2013

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   This is as I did in my branch:

   https://github.com/metal3d/GoVerbalExpressions/blob/and-or-implementation/verbalexpressions.go#L329

   See Or() and And() methods that accept VerbalExpression Objects as argument. My test:
   https://github.com/metal3d/GoVerbalExpressions/blob/and-or-implementation/verbalexpressions_test.go#L545
   works like a charm.

   Other Test for basic "Or":
   https://github.com/metal3d/GoVerbalExpressions/blob/and-or-implementation/verbalexpressions_test.go#L259
   where I create new object as argument (Or(new...))