Re: StackOverFlowError When Applying Filter to a Stream

Could you expand on this bit please:

In the first case there are simply not enough values left to continue the 
stream.

On Wednesday, 5 August 2015 19:46:47 UTC+1, Simon Schäfer wrote:
>
> The first time, the filter is part of fibs, the second time it is part of 
> another stream accessing fibs. In the first case there are simply not 
> enough values left to continue the stream.
>
> On 05.08.2015 20:16, [email protected] <javascript:> wrote:
>
> Hello,
>
>
> Please can some one explain why the following code blows the stack:
>
>  val fibs: Stream[BigInt] = BigInt(0) #:: BigInt(1) #:: fibs.zip(fibs.tail).map { n => n._1 + n._2 }.takeWhile(x => x < 4000000).filter(x => x % 2 == 0)
>
> scala> fibs foreach println01
> java.lang.StackOverflowError
>
> If I take out the filter and apply it to the stream in another expression 
> as follows, it is fine:
>
> scala> val fibs: Stream[BigInt] = BigInt(0) #:: BigInt(1) #:: fibs.zip(fibs.tail).map { n => n._1 + n._2 }.takeWhile(x => x < 4000000)
> fibs: Stream[scala.math.BigInt] = Stream(0, ?)
>
> scala> fibs filter ( x => x % 2 == 0)
> res8: scala.collection.immutable.Stream[scala.math.BigInt] = Stream(0, ?)
>
> scala> fibs filter ( x => x % 2 == 0) foreach println02834144610258410946463681964188320403524578
>
> Why does it blow the stack with the first approach but not the second?
>
>
> Thanks
>
> Iftikhar
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