This patch and the several to follow represent ...

This patch and the several to follow represent an attempt to break
up a very large patch from martin which moves much of the compiler's
typing infrastructure into the library so that we can utilize the same
machinery at runtime that we do at compile time.

Said attempt was not very successful, either at maintaining working
order while committing incrementally or at subdividing the patch into
distinct cohesive units. So let the record show that I tried.

-- some notes on the implementation --

This should not be judged as a finished work, but it's a necessary
opening step for implementing a reflection API without duplicating much
of the compiler.

The files in scala.reflect.common are destined for the library (not the
compiler, where they are now) but have not yet made the leap to manage
compatibility issues.

scala.reflect.generic is likely to be replaced by an alias to
scala.reflect.common.

The fate of scala.reflect.Code and its derived classes is yet to be
determined.

This first patch contains about the only delta against martin's patch,
which is to promote Chars into scala.reflect. Review by odersky.

9 files changed, 100 insertions, 8 deletions

diff --git a/src/compiler/scala/reflect/Chars.scala b/src/compiler/scala/reflect/Chars.scala
new file mode 100644
index 0000000000..739c0ca22b
--- /dev/null
+++ b/src/compiler/scala/reflect/Chars.scala
@@ -0,0 +1,92 @@
+/* NSC -- new Scala compiler
+ * Copyright 2006-2011 LAMP/EPFL
+ * @author  Martin Odersky
+ */
+package scala.reflect
+
+import annotation.{ tailrec, switch }
+import java.lang.{ Character => JCharacter }
+
+/** Contains constants and classifier methods for characters */
+trait Chars {
+  // Be very careful touching these.
+  // Apparently trivial changes to the way you write these constants
+  // will cause Scanners.scala to go from a nice efficient switch to
+  // a ghastly nested if statement which will bring the type checker
+  // to its knees. See ticket #1456
+  // Martin: (this should be verified now that the pattern rules have been redesigned).
+  final val LF = '\u000A'
+  final val FF = '\u000C'
+  final val CR = '\u000D'
+  final val SU = '\u001A'
+
+  /** Convert a character digit to an Int according to given base,
+   *  -1 if no success */
+  def digit2int(ch: Char, base: Int): Int = {
+    if ('0' <= ch && ch <= '9' && ch < '0' + base)
+      ch - '0'
+    else if ('A' <= ch && ch < 'A' + base - 10)
+      ch - 'A' + 10
+    else if ('a' <= ch && ch < 'a' + base - 10)
+      ch - 'a' + 10
+    else
+      -1
+  }
+
+  /** Convert a character to a backslash-u escape */
+  def char2uescape(c: Char): String = {
+    var rest = c.toInt
+    val buf = new StringBuilder
+    for (i <- 1 to 4) {
+      buf ++= (rest % 16).toHexString
+      rest = rest / 16
+    }
+    "\\u" + buf.toString.reverse
+  }
+
+  /** Is character a line break? */
+  @inline def isLineBreakChar(c: Char) = (c: @switch) match {
+    case LF|FF|CR|SU  => true
+    case _            => false
+  }
+
+  /** Is character a whitespace character (but not a new line)? */
+  def isWhitespace(c: Char) =
+    c == ' ' || c == '\t' || c == CR
+
+  /** Can character form part of a doc comment variable $xxx? */
+  def isVarPart(c: Char) =
+    '0' <= c && c <= '9' || 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z'
+
+  /** Can character start an alphanumeric Scala identifier? */
+  def isIdentifierStart(c: Char): Boolean =
+    (c == '_') || (c == '$') || Character.isUnicodeIdentifierStart(c)
+
+  /** Can character form part of an alphanumeric Scala identifier? */
+  def isIdentifierPart(c: Char) =
+    (c == '$') || Character.isUnicodeIdentifierPart(c)
+
+  /** Is character a math or other symbol in Unicode?  */
+  def isSpecial(c: Char) = {
+    val chtp = Character.getType(c)
+    chtp == Character.MATH_SYMBOL.toInt || chtp == Character.OTHER_SYMBOL.toInt
+  }
+
+  private final val otherLetters = Set[Char]('\u0024', '\u005F')  // '$' and '_'
+  private final val letterGroups = {
+    import JCharacter._
+    Set[Byte](LOWERCASE_LETTER, UPPERCASE_LETTER, OTHER_LETTER, TITLECASE_LETTER, LETTER_NUMBER)
+  }
+  def isScalaLetter(ch: Char) = letterGroups(JCharacter.getType(ch).toByte) || otherLetters(ch)
+
+  /** Can character form part of a Scala operator name? */
+  def isOperatorPart(c : Char) : Boolean = (c: @switch) match {
+    case '~' | '!' | '@' | '#' | '%' |
+         '^' | '*' | '+' | '-' | '<' |
+         '>' | '?' | ':' | '=' | '&' |
+         '|' | '/' | '\\' => true
+    case c => isSpecial(c)
+  }
+}
+
+object Chars extends Chars { }
diff --git a/src/compiler/scala/tools/nsc/ast/DocComments.scala b/src/compiler/scala/tools/nsc/ast/DocComments.scala
index 5d276e2004..be729904db 100755
--- a/src/compiler/scala/tools/nsc/ast/DocComments.scala
+++ b/src/compiler/scala/tools/nsc/ast/DocComments.scala
@@ -10,7 +10,7 @@ import symtab._
 import reporters.Reporter
 import util.{Position, NoPosition}
 import util.DocStrings._
-import util.Chars._
+import scala.reflect.Chars._
 import scala.collection.mutable.{HashMap, ListBuffer, StringBuilder}
 
 /*
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
index 3208615757..78bfa1f5ff 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala
@@ -6,7 +6,7 @@ package scala.tools.nsc
 package ast.parser
 
 import scala.tools.nsc.util._
-import Chars._
+import scala.reflect.Chars._
 import Tokens._
 import scala.annotation.switch
 import scala.collection.mutable.{ ListBuffer, ArrayBuffer }
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Tokens.scala b/src/compiler/scala/tools/nsc/ast/parser/Tokens.scala
index e530b725e3..533690fe2e 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Tokens.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Tokens.scala
@@ -13,7 +13,7 @@ import annotation.switch
  *  identical token sets.
  */
 abstract class Tokens {
-  import util.Chars._
+  import scala.reflect.Chars._
 
   /** special tokens */
   final val EMPTY = -3
diff --git a/src/compiler/scala/tools/nsc/javac/JavaScanners.scala b/src/compiler/scala/tools/nsc/javac/JavaScanners.scala
index ed5ebb1a01..841b28c56f 100644
--- a/src/compiler/scala/tools/nsc/javac/JavaScanners.scala
+++ b/src/compiler/scala/tools/nsc/javac/JavaScanners.scala
@@ -7,7 +7,7 @@ package scala.tools.nsc
 package javac
 
 import scala.tools.nsc.util._
-import Chars._
+import scala.reflect.Chars._
 import JavaTokens._
 import scala.annotation.switch
 
diff --git a/src/compiler/scala/tools/nsc/util/CharArrayReader.scala b/src/compiler/scala/tools/nsc/util/CharArrayReader.scala
index bdf33476cc..e38f99b42c 100644
--- a/src/compiler/scala/tools/nsc/util/CharArrayReader.scala
+++ b/src/compiler/scala/tools/nsc/util/CharArrayReader.scala
@@ -6,7 +6,7 @@
 package scala.tools.nsc
 package util
 
-import Chars._
+import scala.reflect.Chars._
 
 abstract class CharArrayReader { self =>
 
diff --git a/src/compiler/scala/tools/nsc/util/DocStrings.scala b/src/compiler/scala/tools/nsc/util/DocStrings.scala
index ecac4f7755..014c90365c 100755
--- a/src/compiler/scala/tools/nsc/util/DocStrings.scala
+++ b/src/compiler/scala/tools/nsc/util/DocStrings.scala
@@ -7,7 +7,7 @@
 package scala.tools.nsc
 package util
 
-import Chars._
+import scala.reflect.Chars._
 import scala.collection.mutable.{HashMap, ListBuffer, StringBuilder}
 
 /** Utilitity methods for doc comment strings
diff --git a/src/compiler/scala/tools/nsc/util/JavaCharArrayReader.scala b/src/compiler/scala/tools/nsc/util/JavaCharArrayReader.scala
index f27d25d1b0..98ec4dc29b 100644
--- a/src/compiler/scala/tools/nsc/util/JavaCharArrayReader.scala
+++ b/src/compiler/scala/tools/nsc/util/JavaCharArrayReader.scala
@@ -6,7 +6,7 @@
 package scala.tools.nsc
 package util
 
-import Chars._
+import scala.reflect.Chars._
 
 class JavaCharArrayReader(buf: IndexedSeq[Char], start: Int, /* startline: int, startcol: int, */
                       decodeUni: Boolean, error: String => Unit) extends Iterator[Char] with Cloneable {
diff --git a/src/compiler/scala/tools/nsc/util/SourceFile.scala b/src/compiler/scala/tools/nsc/util/SourceFile.scala
index 90a9057f01..5ab4a5cee3 100644
--- a/src/compiler/scala/tools/nsc/util/SourceFile.scala
+++ b/src/compiler/scala/tools/nsc/util/SourceFile.scala
@@ -12,7 +12,7 @@ import scala.collection.mutable.ArrayBuffer
 import annotation.tailrec
 import java.util.regex.Pattern
 import java.io.IOException
-import Chars._
+import scala.reflect.Chars._
 
 /** abstract base class of a source file used in the compiler */
 abstract class SourceFile {