Implementing class for pattern matching

Posted by Jeriho on Stack Overflow See other posts from Stack Overflow or by Jeriho
Published on 2010-05-24T20:56:17Z Indexed on 2010/05/24 21:01 UTC
Read the original article Hit count: 168

Filed under:

scala

|

pattern-matching

For example,

val list = List(1,2,3)
list match{
  case a:::b => 
  case _ => 
}

you can match head and tail of a List using :::' or tokens of ParseResult using~'. What should I do to create class that can be matched like preceding classes?

© 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 pattern-matching

A couple of pattern matching issues with pattern matching in Lua

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm fairly new to lua programming, but I'm also a quick study. I've been working on a weather forecaster for a program that I use, and it's working well, for the most part. Here is what I have so far. (Pay no attention to the zs.stuff. That is program specific and has no bearing on the lua coding… >>> More
pattern matching in .Net consistent with IsolatedStorageFile.GetFileNames() pattern matching

as seen on Stack Overflow - Search for 'Stack Overflow'
Is the pattern matching logic used by this API exposed for reuse somewhere in the .Net Framework? Something of the form FilePatternMatch( string searchPattern, stringfileNameToTest ) is what I'm looking for. I'm implementing a temporary workaround for WP7 not filtering the results for this overload… >>> More
pattern matching in Bash

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, Here is an example to get different parts of a filename bash-3.2$ pathandfile=/tmp/ff.txt bash-3.2$ filename=$(basename $pathandfile) bash-3.2$ echo $filename ff.txt bash-3.2$ echo ${filename##*.} txt bash-3.2$ echo ${filename%.*} ff I was wondering what does ##… >>> More
What is a 'Pattern Matching' in functional languages?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm reading about functional programming (in academic purpose) and I've noticed that Pattern Matching is mentioned in many articles as one of the core features of functional languages. Can someone explain for a java/c++/javascript developer what does it mean? >>> More
Lua pattern matching vs. regular expressions

as seen on Stack Overflow - Search for 'Stack Overflow'
hello, i'm currently learning lua. regarding pattern-matching in lua i found the following sentence in the lua documentation on lua.org: Nevertheless, pattern matching in Lua is a powerful tool and includes some features that are difficult to match with standard POSIX implementations. as i'm… >>> More