Takes 30+% off the startup time for scala/scala...

Takes 30+% off the startup time for scala/scalac with a variety of
optimizations pinpointed by tracing method invocations. Frequent guest
stars in the parade of slowness were: using Lists and ListBuffers when
any amount of random access is needed, using Strings as if one shouldn't
have to supply 80 characters of .substring noise to drop a character
here and there, imagining that code can be reused in any way shape
or form without a savage slowness burn being unleashed upon you and
everything you have ever loved, String.format, methods which return
tuples, and any method written with appealing scala features which turns
out to be called a few orders of magnitude more often than the author
probably supposed.

This may be only the tip of the iceberg. No review.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/library/scala/collection/immutable/StringOps.scala b/src/library/scala/collection/immutable/StringOps.scala
index 63d5984b11..5fc71c7259 100644
--- a/src/library/scala/collection/immutable/StringOps.scala
+++ b/src/library/scala/collection/immutable/StringOps.scala
@@ -36,7 +36,17 @@ final class StringOps(override val repr: String) extends StringLike[String] {
   /** Creates a string builder buffer as builder for this class */
   override protected[this] def newBuilder = StringBuilder.newBuilder
 
+  override def apply(index: Int): Char = repr charAt index
+  override def slice(from: Int, until: Int): String = {
+    val start = if (from < 0) 0 else from
+    if (until <= start || start >= repr.length)
+      return ""
+
+    val end = if (until > length) length else until
+    repr.substring(start, end)
+  }
   override def toString = repr
+  override def length = repr.length
 
   def seq = this.iterator
 }