Combining / Concatenating Two PathSet

[Randall R Schulz]

Hello,

I would like to take two PathSet and join / concatenate them prior to applying take(n: Int) and then toSeq.

How can I do that? The code I have won't compile because of a type mismatch:

  val batchPaths =
    trashDirs.foldLeft(PathSet[Path]()) { (pathSet, trashPath: Path) =>
      val eligible = eligibleInDir(trashPath, perDirLimit)
      newlyEncountered ++= namesToTrack
      pathSet ++ eligible
    }

The compiler complains thusly about the line shown in red above:

[error]  found   : scalax.file.PathSet[scalax.file.Path]
[error]  required: scalax.file.BasicPathSet[scalax.file.Path]
[error]           pathSet ++ eligible
[error]                   ^

Randall Schulz

[Randall R Schulz]

I should have said that eligibleInDir returns PathSet[Path].

[jesse....@gmail.com]

I will take a look but that looks like a bug to me.  I probably have some invariance wrong or perhaps the BasicPathSet signature is leaking out but shouldn’t be leaking.

 

As a workaround can you cast the BasicPathSet to a PathSet?

 

Could you fill out this code snippet and put it on a Github issue?  That will make it easier for me to debug.

 

Thanks,

 

Jesse

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[Randall R Schulz]

An update:

If I do this, the code compiles:

val emptyPathSet: PathSet[Path] = PathSet[Path]()
val batchPaths =
    trashDirs.foldLeft(emptyPathSet) { (pathSet, trashPath) =>
      val eligible = eligibleInDir(trashPath, perDirLimit)

[jesse....@gmail.com]

oh of course that makes sense.  It is the expectation you are setting at the beginning of the foldLeft.  the factory method PathSet[PathSet]() must return something of type BasicPathSet[Path].  (It shouldn’t)  I probably have to explicitely state the return type.  I will take a look at that.

 

From: Randall R Schulz
Sent: ‎March‎ ‎14‎, ‎2013 ‎8‎:‎03‎ ‎PM
To: scala-i...@googlegroups.com
Subject: Re: Combining / Concatenating Two PathSet

 

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