From 47d1fb1e9975998d5f8dde63c08c0b3ab1cd5ae2 Mon Sep 17 00:00:00 2001 From: Eugene Burmako Date: Wed, 22 Jan 2014 18:53:02 +0300 Subject: SI-6879 improves Context.freshName MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of per-compilation unit unique counters, the freshName API now uses a per-Global counter. Fresh names now also contain dollars to exclude clashes with supported user-defined names (the ones without dollar signs). This doesn’t fix the bug, because per-Global counters get created anew every time a new Global is instantiated, and that provides some potential for name clashes even for def macros, but at least it completely excludes clashes in typical situations. --- src/reflect/scala/reflect/internal/StdNames.scala | 2 ++ .../scala/reflect/internal/SymbolTable.scala | 4 +++ src/reflect/scala/reflect/macros/Names.scala | 40 ++++++++++++++++------ .../scala/reflect/runtime/JavaUniverse.scala | 2 +- 4 files changed, 36 insertions(+), 12 deletions(-) (limited to 'src/reflect') diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala index ed3e7dbc4c..7015105261 100644 --- a/src/reflect/scala/reflect/internal/StdNames.scala +++ b/src/reflect/scala/reflect/internal/StdNames.scala @@ -305,6 +305,8 @@ trait StdNames { val PROTECTED_SET_PREFIX = PROTECTED_PREFIX + "set" val SUPER_PREFIX_STRING = "super$" val WHILE_PREFIX = "while$" + val FRESH_PREFIX = "fresh" + val FRESH_SUFFIX = "macro$" // uses a keyword to avoid collisions with mangled names // Compiler internal names val ANYname: NameType = "" diff --git a/src/reflect/scala/reflect/internal/SymbolTable.scala b/src/reflect/scala/reflect/internal/SymbolTable.scala index 571c4cfa5d..733eecf3f6 100644 --- a/src/reflect/scala/reflect/internal/SymbolTable.scala +++ b/src/reflect/scala/reflect/internal/SymbolTable.scala @@ -141,6 +141,10 @@ abstract class SymbolTable extends macros.Universe ) } + // SI-6879 Keeps track of counters that are supposed to be globally unique + // as opposed to traditional freshers that are unique to compilation units. + val globalFreshNameCreator = new FreshNameCreator + /** Dump each symbol to stdout after shutdown. */ final val traceSymbolActivity = sys.props contains "scalac.debug.syms" diff --git a/src/reflect/scala/reflect/macros/Names.scala b/src/reflect/scala/reflect/macros/Names.scala index af60dffbfc..4f3448e1ed 100644 --- a/src/reflect/scala/reflect/macros/Names.scala +++ b/src/reflect/scala/reflect/macros/Names.scala @@ -6,33 +6,51 @@ package macros * EXPERIMENTAL * * A slice of [[scala.reflect.macros.blackbox.Context the Scala macros context]] that - * provides functions that generate unique names. + * provides functions that generate fresh names. + * + * In the current implementation, fresh names are more or less unique in the sense that + * within the same compilation run they are guaranteed not to clash with: + * 1) Results of past and future invocations of functions of `freshName` family + * 2) User-defined or macro-generated names that don't contain dollar symbols + * 3) Macro-generated names that are created by concatenating names from the first, second and third categories + * + * Uniqueness of fresh names across compilation runs is not guaranteed, but that's something + * that we would like to improve upon in future releases. See [[https://issues.scala-lang.org/browse/SI-6879]] for more information. + * + * @define freshNameNoParams + * Creates a string that represents a more or less unique name. + * Consult [[scala.reflect.macros.Names]] for more information on uniqueness of such names. + * + * @define freshNameStringParam + * Creates a string that represents a more or less unique name having a given prefix. + * Consult [[scala.reflect.macros.Names]] for more information on uniqueness of such names. + * + * @define freshNameNameParam + * Creates a more or less unique name having a given name as a prefix and + * having the same flavor (term name or type name) as the given name. + * Consult [[scala.reflect.macros.Names]] for more information on uniqueness of such names. */ trait Names { self: blackbox.Context => - /** Creates a unique string. */ + /** $freshNameNoParams */ @deprecated("Use freshName instead", "2.11.0") def fresh(): String - /** Creates a unique string having a given prefix. */ + /** $freshNameStringParam */ @deprecated("Use freshName instead", "2.11.0") def fresh(name: String): String - /** Creates a unique name having a given name as a prefix and - * having the same flavor (term name or type name) as the given name. - */ + /** $freshNameNameParam */ @deprecated("Use freshName instead", "2.11.0") def fresh[NameType <: Name](name: NameType): NameType - /** Creates a unique string. */ + /** $freshNameNoParams */ def freshName(): String - /** Creates a unique string having a given prefix. */ + /** $freshNameStringParam */ def freshName(name: String): String - /** Creates a unique name having a given name as a prefix and - * having the same flavor (term name or type name) as the given name. - */ + /** $freshNameNameParam */ def freshName[NameType <: Name](name: NameType): NameType } diff --git a/src/reflect/scala/reflect/runtime/JavaUniverse.scala b/src/reflect/scala/reflect/runtime/JavaUniverse.scala index 54b75b8e5b..cfd66744ff 100644 --- a/src/reflect/scala/reflect/runtime/JavaUniverse.scala +++ b/src/reflect/scala/reflect/runtime/JavaUniverse.scala @@ -21,7 +21,7 @@ class JavaUniverse extends internal.SymbolTable with JavaUniverseForce with Refl def newStrictTreeCopier: TreeCopier = new StrictTreeCopier def newLazyTreeCopier: TreeCopier = new LazyTreeCopier - val currentFreshNameCreator = new reflect.internal.util.FreshNameCreator + def currentFreshNameCreator = globalFreshNameCreator // can't put this in runtime.Trees since that's mixed with Global in ReflectGlobal, which has the definition from internal.Trees object treeInfo extends { -- cgit v1.2.3