regex in scala interpreter

[Jose Francisco Gonzalez]

I'm trying to use regex in a simple script (splitter.scala) using
the latest version of scala

>> Scala code runner version 2.9.0.1 -- Copyright 2002-2011, LAMP/EPFL

****BEGIN SCALA SCRIPT****
val data = "<a>aaaaa</a><b>bbbbbb</b><c>ccccccc</c>"

val p = "^<a>(.+)</a><b>(.+)</b><c>(.+)</c>$".r

val parts = p.findAllIn(data)
val aes = parts.group(1)
val bes = parts.group(2)
val ces = parts.group(3)

Console.println(aes)
****END SCALA SCRIPT****

executing it with

jfglez@Platea:~/Documentos/scala/m200$ scala splitter.scala

i get the following error:

java.lang.IllegalStateException: No match available
at java.util.regex.Matcher.start(Matcher.java:355)
at scala.util.matching.Regex$MatchIterator.start(Regex.scala:316)
at scala.util.matching.Regex$MatchData$class.group(Regex.scala:198)
at scala.util.matching.Regex$MatchIterator.group(Regex.scala:291)
at Main$$anon$1.<init>(splitter.scala:8)
at Main$.main(splitter.scala:1)
at Main.main(splitter.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
....

but executing line by line the above script on a scala console,
the "script" works.

where is the problem with the script?.

Some advice will be welcome

jfglez

[Ken McDonald]

Try taking out the "^" and "$" in the regex--they are affected by flags, I believe, which could be one (unlikely) source of variability.

If you will be using more complex regexes, you might want to check out http://kenmcdonald.github.com/rex .

Cheers,

Ken

[Daniel Sobral]

You *really* shouldn't call "group" on a MatchIterator, no matter what
the API says. The problem is that, at the time you call "group", no
matching was made yet! You haven't called "next" or anything to make
the match happen. If you type it on REPL, it works because "hasNext",
used to print the iterator, causes the match to be made.

You should iterate over the result of findAllIn to use it -- foreach,
flatMap, map...

--
Daniel C. Sobral

I travel to the future all the time.