Invalid stubs for Scala (Uppercase Variables)

Feedback & Bugs
#1

I encountered the bug in Mime Types puzzle

mime type line contains two “words” separated by a space
stubs for reading it looks like this:

val Array(EXT, MT) = readLine split " "

and it produces following errors:

/tmp/Solution.scala:14: error: not found: value EXT
        val Array(EXT, MT) = readLine split " "
                  ^
/tmp/Solution.scala:14: error: not found: value MT
        val Array(EXT, MT) = readLine split " "
                       ^

the thing is that this code uses patter matching and identifiers that starts with upper case letters are treated like constants to match against (so called “stable identifiers”).

https://www.scala-lang.org/files/archive/spec/2.11/08-pattern-matching.html#stable-identifier-patterns

this code can be fixed in two ways.
First (good and canonical) way is to convert variables into lower case:

val Array(ext, mt) = readLine split " "

Second way, ugly and bad, is to read result into separate array variable and extract values later:

val inputs = readLine split " "
val EXT = inputs(0)
val MT = inputs(1)
1 Like
#2

indeed, same problem has been reported on Mars Lander puzzle a few months ago. It’s still in our bugs backlog. Thanks for reporting it.