Re^2: nested #if directive matching matching

choroba:

Actually, you *do* need a stack if you're going to properly handle the #else clauses. Otherwise, you won't remember the previous value(s) of the print vs. don't print states.

#if 0
  this shouldn't print
  #if 1
     nor should this
  #else
     nor this
  #end
#else
  but this should
  #if 1
     as should this
  #else
     but not this
  #end
  This should print, but where are you storing the information
  to know it without a stack?
#else
  If you got that one right, howzabout this one?
#end
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...roboticus

When your only tool is a hammer, all problems look like your thumb.

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Re^3: nested #if directive matching matching by choroba (Cardinal) on Jun 26, 2012 at 12:53 UTC
That was not part of the spec :-)	[reply]
Re^4: nested #if directive matching matching by Anonymous Monk on Jun 26, 2012 at 19:35 UTC
Using the counter, bitshift left and increment if true. Else is an XOR 1. Endif is a bitshift right. Initialize with a sentinel value so you know when you're done.	[reply]
Re^5: nested #if directive matching matching by GrandFather (Saint) on Jun 26, 2012 at 21:13 UTC
That is a stack. Not an overly deep one, but probably sufficient for the purpose. True laziness is hard work	[reply]