Extending existing data structure in Scala.

Posted by Lukasz Lew on Stack Overflow See other posts from Stack Overflow or by Lukasz Lew
Published on 2010-05-09T09:19:09Z Indexed on 2010/05/09 9:28 UTC
Read the original article Hit count: 208

Filed under:

scala

|

scala-2.8

|

data-structures

I have a normal tree defined in Scala.

sealed abstract class Tree
case class Node (...) extends Tree
case class Leaf (...) extends Tree

Now I want to add a member variable to all nodes and leaves in the tree. Is it possible with extend keyword or do I have to modify the tree classes by adding [T]?

© Stack Overflow or respective owner

Related posts about scala

ensime scala errors (class scala.Array not found, object scala not found)

as seen on Stack Overflow - Search for 'Stack Overflow'
I've installed ensime according to the README.md file, however, I get errors in the inferior-ensime-server buffer with the following: INFO: Fatal Error: scala.tools.nsc.MissingRequirementError: object scala not found. scala.tools.nsc.MissingRequirementError: object scala not found. at scala… >>> More
infinite loop shutting down ensime

as seen on Stack Overflow - Search for 'Stack Overflow'
When I run M-X ensime-disconnect I get the following forever: string matching regex `\"((?:[^\"\\]|\\.)*)\"' expected but `^@' found and I see this exception when I use C-c C-c Uncaught exception in com.ensime.server.SocketHandler@769aba32 java.net.SocketException: Broken pipe at java… >>> More
How to resolve java.nio.charset.UnmappableCharacterException in Scala 2.8.0?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm using Scala 2.8.0 and trying to read pipe delimited file like in code snipped below: object Main { def main(args: Array[String]) :Unit = { if (args.length > 0) { val lines = scala.io.Source.fromPath("QUICK!LRU-2009-11-15.psv") for (line <-lines) print(line) } … >>> More
Question on Scala Closure (From "Programming in Scala")

as seen on Stack Overflow - Search for 'Stack Overflow'
I don't understand why authors said that Code Listing 9.1 from "Programming in Scala" use closure. In chapter 9, they show how to refactor code into more less duplicated form, from this original code: object FileMatcher { private def filesHere = (new java.io.File(".")).listFiles def filesEnding(query:… >>> More
Common idiom in Java to Scala, traverse/Iterate Java list into Scala list

as seen on Stack Overflow - Search for 'Stack Overflow'
I am processing a XML document and iterating through nodes. I want to iterate through the nodes and build a new List of some type. How would I do this with Scala: Here is my XML traverse code: def findClassRef(xmlNode: Elem) = { xmlNode\"classDef" foreach { (entry) => val name… >>> More

Related posts about scala-2.8

ensime scala errors (class scala.Array not found, object scala not found)

as seen on Stack Overflow - Search for 'Stack Overflow'
I've installed ensime according to the README.md file, however, I get errors in the inferior-ensime-server buffer with the following: INFO: Fatal Error: scala.tools.nsc.MissingRequirementError: object scala not found. scala.tools.nsc.MissingRequirementError: object scala not found. at scala… >>> More
infinite loop shutting down ensime

as seen on Stack Overflow - Search for 'Stack Overflow'
When I run M-X ensime-disconnect I get the following forever: string matching regex `\"((?:[^\"\\]|\\.)*)\"' expected but `^@' found and I see this exception when I use C-c C-c Uncaught exception in com.ensime.server.SocketHandler@769aba32 java.net.SocketException: Broken pipe at java… >>> More
How to resolve java.nio.charset.UnmappableCharacterException in Scala 2.8.0?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm using Scala 2.8.0 and trying to read pipe delimited file like in code snipped below: object Main { def main(args: Array[String]) :Unit = { if (args.length > 0) { val lines = scala.io.Source.fromPath("QUICK!LRU-2009-11-15.psv") for (line <-lines) print(line) } … >>> More
Question on Scala Closure (From "Programming in Scala")

as seen on Stack Overflow - Search for 'Stack Overflow'
I don't understand why authors said that Code Listing 9.1 from "Programming in Scala" use closure. In chapter 9, they show how to refactor code into more less duplicated form, from this original code: object FileMatcher { private def filesHere = (new java.io.File(".")).listFiles def filesEnding(query:… >>> More
Common idiom in Java to Scala, traverse/Iterate Java list into Scala list

as seen on Stack Overflow - Search for 'Stack Overflow'
I am processing a XML document and iterating through nodes. I want to iterate through the nodes and build a new List of some type. How would I do this with Scala: Here is my XML traverse code: def findClassRef(xmlNode: Elem) = { xmlNode\"classDef" foreach { (entry) => val name… >>> More