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1790 :: filter(map(...

• mora (orginal) [2015-11-10T20:58:43+01:00] view original

  Hi,

  I remember reading a presentation which said that Nim could replace s.add("a").add("b") to s.add("ab") at compile time. I'm just curious, if I have a code like this:

  echo len(mySeq) # that is 1.000.000 int elements, mostly random
  echo map(mySeq, x=>x+1).filter(x mod 94117 == 3) # this prints only 10 elements
  Run

  Then my question is: could we create a rule to replace filter(map(...)) in this case to filter(mapReturingAnIteratorInsteadOfStoringAllTheResults(...))? I would like to avoid storing the intermediate values. In this case it is clear that there is no need to allocate 1MM ints (again).

  Thanks,

  Peter

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• jlp765 (orginal) [2015-11-11T03:11:49+01:00] view original

  This is one means of joining terms:

  
  template doJoin(a,b: expr): expr =
    proc `a b`() = echo "Hello"
  
  doJoin(ebony, ivory)
  
  ebonyivory()
  Run

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• Araq (orginal) [2015-11-11T08:02:58+01:00] view original

  Yes. http://nim-lang.org/docs/manual.html#term-rewriting-macros

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