Next generation of macros

Implements SIP 16: Self-cleaning macros: http://bit.ly/wjjXTZ

Features:
* Macro defs
* Reification
* Type tags
* Manifests aliased to type tags
* Extended reflection API
* Several hundred tests
* 1111 changed files

Not yet implemented:
* Reification of refined types
* Expr.value splicing
* Named and default macro expansions
* Intricacies of interaction between macros and implicits
* Emission of debug information for macros (compliant with JSR-45)

Dedicated to Yuri Alekseyevich Gagarin

1 files changed, 53 insertions, 0 deletions

diff --git a/src/library/scala/reflect/makro/Enclosures.scala b/src/library/scala/reflect/makro/Enclosures.scala
new file mode 100644
index 0000000000..136d39498e
--- /dev/null
+++ b/src/library/scala/reflect/makro/Enclosures.scala
@@ -0,0 +1,53 @@
+package scala.reflect.makro
+
+trait Enclosures {
+  self: Context =>
+
+  /** The tree that undergoes macro expansion.
+   *  Can be useful to get an offset or a range position of the entire tree being processed.
+   */
+  val macroApplication: Tree
+
+  /** Contexts that represent macros in-flight, including the current one. Very much like a stack trace, but for macros only.
+   *  Can be useful for interoperating with other macros and for imposing compiler-friendly limits on macro expansion.
+   *
+   *  Is also priceless for emitting sane error messages for macros that are called by other macros on synthetic (i.e. position-less) trees.
+   *  In that dire case navigate the ``enclosingMacros'' stack, and it will most likely contain at least one macro with a position-ful macro application.
+   *  See ``enclosingPosition'' for a default implementation of this logic.
+   *
+   *  Unlike `openMacros`, this is a val, which means that it gets initialized when the context is created
+   *  and always stays the same regardless of whatever happens during macro expansion.
+   */
+  val enclosingMacros: List[Context]
+
+  /** Types along with corresponding trees for which implicit arguments are currently searched.
+   *  Can be useful to get information about an application with an implicit parameter that is materialized during current macro expansion.
+   *
+   *  Unlike `openImplicits`, this is a val, which means that it gets initialized when the context is created
+   *  and always stays the same regardless of whatever happens during macro expansion.
+   */
+  val enclosingImplicits: List[(Type, Tree)]
+
+  /** Tries to guess a position for the enclosing application.
+   *  But that is simple, right? Just dereference ``pos'' of ``macroApplication''? Not really.
+   *  If we're in a synthetic macro expansion (no positions), we must do our best to infer the position of something that triggerd this expansion.
+   *  Surprisingly, quite often we can do this by navigation the ``enclosingMacros'' stack.
+   */
+  val enclosingPosition: Position
+
+  /** Tree that corresponds to the enclosing application, or EmptyTree if not applicable.
+   */
+  val enclosingApplication: Tree
+
+  /** Tree that corresponds to the enclosing method, or EmptyTree if not applicable.
+   */
+  val enclosingMethod: Tree
+
+  /** Tree that corresponds to the enclosing class, or EmptyTree if not applicable.
+   */
+  val enclosingClass: Tree
+
+  /** Compilation unit that contains this macro application.
+   */
+  val enclosingUnit: CompilationUnit
+}
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