diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala | 283 |
1 files changed, 246 insertions, 37 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala index 54e4fefc15..fa6e5399eb 100644 --- a/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala +++ b/src/compiler/scala/tools/nsc/typechecker/AnalyzerPlugins.scala @@ -13,7 +13,6 @@ package typechecker trait AnalyzerPlugins { self: Analyzer => import global._ - trait AnalyzerPlugin { /** * Selectively activate this analyzer plugin, e.g. according to the compiler phase. @@ -156,6 +155,117 @@ trait AnalyzerPlugins { self: Analyzer => def pluginsTypedReturn(tpe: Type, typer: Typer, tree: Return, pt: Type): Type = tpe } + /** + * @define nonCumulativeReturnValueDoc Returns `None` if the plugin doesn't want to customize the default behavior + * or something else if the plugin knows better that the implementation provided in scala-compiler.jar. + * If multiple plugins return a non-empty result, it's going to be a compilation error. + */ + trait MacroPlugin { + /** + * Selectively activate this analyzer plugin, e.g. according to the compiler phase. + * + * Note that the current phase can differ from the global compiler phase (look for `enteringPhase` + * invocations in the compiler). For instance, lazy types created by the UnPickler are completed + * at the phase in which their symbol is created. Observations show that this can even be the + * parser phase. Since symbol completion can trigger subtyping, typing etc, your plugin might + * need to be active also in phases other than namer and typer. + * + * Typically, this method can be implemented as + * + * global.phase.id < global.currentRun.picklerPhase.id + */ + def isActive(): Boolean = true + + /** + * Typechecks the right-hand side of a macro definition (which typically features + * a mere reference to a macro implementation). + * + * Default implementation provided in `self.standardTypedMacroBody` makes sure that the rhs + * resolves to a reference to a method in either a static object or a macro bundle, + * verifies that the referred method is compatible with the macro def and upon success + * attaches a macro impl binding to the macro def's symbol. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsTypedMacroBody(typer: Typer, ddef: DefDef): Option[Tree] = None + + /** + * Expands an application of a def macro (i.e. of a symbol that has the MACRO flag set), + * possibly using the current typer mode and the provided prototype. + * + * Default implementation provided in `self.standardMacroExpand` figures out whether the `expandee` + * needs to be expanded right away or its expansion has to be delayed until all undetermined + * parameters are inferred, then loads the macro implementation using `self.pluginsMacroRuntime`, + * prepares the invocation arguments for the macro implementation using `self.pluginsMacroArgs`, + * and finally calls into the macro implementation. After the call returns, it typechecks + * the expansion and performs some bookkeeping. + * + * This method is typically implemented if your plugin requires significant changes to the macro engine. + * If you only need to customize the macro context, consider implementing `pluginsMacroArgs`. + * If you only need to customize how macro implementation are invoked, consider going for `pluginsMacroRuntime`. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsMacroExpand(typer: Typer, expandee: Tree, mode: Mode, pt: Type): Option[Tree] = None + + /** + * Computes the arguments that need to be passed to the macro impl corresponding to a particular expandee. + * + * Default implementation provided in `self.standardMacroArgs` instantiates a `scala.reflect.macros.contexts.Context`, + * gathers type and value arguments of the macro application and throws them together into `MacroArgs`. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsMacroArgs(typer: Typer, expandee: Tree): Option[MacroArgs] = None + + /** + * Summons a function that encapsulates macro implementation invocations for a particular expandee. + * + * Default implementation provided in `self.standardMacroRuntime` returns a function that + * loads the macro implementation binding from the macro definition symbol, + * then uses either Java or Scala reflection to acquire the method that corresponds to the impl, + * and then reflectively calls into that method. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsMacroRuntime(expandee: Tree): Option[MacroRuntime] = None + + /** + * Creates a symbol for the given tree in lexical context encapsulated by the given namer. + * + * Default implementation provided in `namer.standardEnterSym` handles MemberDef's and Imports, + * doing nothing for other trees (DocDef's are seen through and rewrapped). Typical implementation + * of `enterSym` for a particular tree flavor creates a corresponding symbol, assigns it to the tree, + * enters the symbol into scope and then might even perform some code generation. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsEnterSym(namer: Namer, tree: Tree): Boolean = false + + /** + * Makes sure that for the given class definition, there exists a companion object definition. + * + * Default implementation provided in `namer.standardEnsureCompanionObject` looks up a companion symbol for the class definition + * and then checks whether the resulting symbol exists or not. If it exists, then nothing else is done. + * If not, a synthetic object definition is created using the provided factory, which is then entered into namer's scope. + * + * $nonCumulativeReturnValueDoc. + */ + def pluginsEnsureCompanionObject(namer: Namer, cdef: ClassDef, creator: ClassDef => Tree = companionModuleDef(_)): Option[Symbol] = None + + /** + * Prepares a list of statements for being typechecked by performing domain-specific type-agnostic code synthesis. + * + * Trees passed into this method are going to be named, but not typed. + * In particular, you can rely on the compiler having called `enterSym` on every stat prior to passing calling this method. + * + * Default implementation does nothing. Current approaches to code syntheses (generation of underlying fields + * for getters/setters, creation of companion objects for case classes, etc) are too disparate and ad-hoc + * to be treated uniformly, so I'm leaving this for future work. + */ + def pluginsEnterStats(typer: Typer, stats: List[Tree]): List[Tree] = stats + } + /** A list of registered analyzer plugins */ @@ -167,59 +277,158 @@ trait AnalyzerPlugins { self: Analyzer => analyzerPlugins = plugin :: analyzerPlugins } + private abstract class CumulativeOp[T] { + def default: T + def accumulate: (T, AnalyzerPlugin) => T + } + + private def invoke[T](op: CumulativeOp[T]): T = { + if (analyzerPlugins.isEmpty) op.default + else analyzerPlugins.foldLeft(op.default)((current, plugin) => + if (!plugin.isActive()) current else op.accumulate(current, plugin)) + } /** @see AnalyzerPlugin.pluginsPt */ def pluginsPt(pt: Type, typer: Typer, tree: Tree, mode: Mode): Type = + // performance opt if (analyzerPlugins.isEmpty) pt - else analyzerPlugins.foldLeft(pt)((pt, plugin) => - if (!plugin.isActive()) pt else plugin.pluginsPt(pt, typer, tree, mode)) + else invoke(new CumulativeOp[Type] { + def default = pt + def accumulate = (pt, p) => p.pluginsPt(pt, typer, tree, mode) + }) /** @see AnalyzerPlugin.pluginsTyped */ - def pluginsTyped(tpe: Type, typer: Typer, tree: Tree, mode: Mode, pt: Type): Type = { - // support deprecated methods in annotation checkers - val annotCheckersTpe = addAnnotations(tree, tpe) - if (analyzerPlugins.isEmpty) annotCheckersTpe - else analyzerPlugins.foldLeft(annotCheckersTpe)((tpe, plugin) => - if (!plugin.isActive()) tpe else plugin.pluginsTyped(tpe, typer, tree, mode, pt)) - } + def pluginsTyped(tpe: Type, typer: Typer, tree: Tree, mode: Mode, pt: Type): Type = + // performance opt + if (analyzerPlugins.isEmpty) addAnnotations(tree, tpe) + else invoke(new CumulativeOp[Type] { + // support deprecated methods in annotation checkers + def default = addAnnotations(tree, tpe) + def accumulate = (tpe, p) => p.pluginsTyped(tpe, typer, tree, mode, pt) + }) /** @see AnalyzerPlugin.pluginsTypeSig */ - def pluginsTypeSig(tpe: Type, typer: Typer, defTree: Tree, pt: Type): Type = - if (analyzerPlugins.isEmpty) tpe - else analyzerPlugins.foldLeft(tpe)((tpe, plugin) => - if (!plugin.isActive()) tpe else plugin.pluginsTypeSig(tpe, typer, defTree, pt)) + def pluginsTypeSig(tpe: Type, typer: Typer, defTree: Tree, pt: Type): Type = invoke(new CumulativeOp[Type] { + def default = tpe + def accumulate = (tpe, p) => p.pluginsTypeSig(tpe, typer, defTree, pt) + }) /** @see AnalyzerPlugin.pluginsTypeSigAccessor */ - def pluginsTypeSigAccessor(tpe: Type, typer: Typer, tree: ValDef, sym: Symbol): Type = - if (analyzerPlugins.isEmpty) tpe - else analyzerPlugins.foldLeft(tpe)((tpe, plugin) => - if (!plugin.isActive()) tpe else plugin.pluginsTypeSigAccessor(tpe, typer, tree, sym)) + def pluginsTypeSigAccessor(tpe: Type, typer: Typer, tree: ValDef, sym: Symbol): Type = invoke(new CumulativeOp[Type] { + def default = tpe + def accumulate = (tpe, p) => p.pluginsTypeSigAccessor(tpe, typer, tree, sym) + }) /** @see AnalyzerPlugin.canAdaptAnnotations */ - def canAdaptAnnotations(tree: Tree, typer: Typer, mode: Mode, pt: Type): Boolean = { + def canAdaptAnnotations(tree: Tree, typer: Typer, mode: Mode, pt: Type): Boolean = invoke(new CumulativeOp[Boolean] { // support deprecated methods in annotation checkers - val annotCheckersExists = global.canAdaptAnnotations(tree, mode, pt) - annotCheckersExists || { - if (analyzerPlugins.isEmpty) false - else analyzerPlugins.exists(plugin => - plugin.isActive() && plugin.canAdaptAnnotations(tree, typer, mode, pt)) - } - } + def default = global.canAdaptAnnotations(tree, mode, pt) + def accumulate = (curr, p) => curr || p.canAdaptAnnotations(tree, typer, mode, pt) + }) /** @see AnalyzerPlugin.adaptAnnotations */ - def adaptAnnotations(tree: Tree, typer: Typer, mode: Mode, pt: Type): Tree = { + def adaptAnnotations(tree: Tree, typer: Typer, mode: Mode, pt: Type): Tree = invoke(new CumulativeOp[Tree] { // support deprecated methods in annotation checkers - val annotCheckersTree = global.adaptAnnotations(tree, mode, pt) - if (analyzerPlugins.isEmpty) annotCheckersTree - else analyzerPlugins.foldLeft(annotCheckersTree)((tree, plugin) => - if (!plugin.isActive()) tree else plugin.adaptAnnotations(tree, typer, mode, pt)) - } + def default = global.adaptAnnotations(tree, mode, pt) + def accumulate = (tree, p) => p.adaptAnnotations(tree, typer, mode, pt) + }) /** @see AnalyzerPlugin.pluginsTypedReturn */ - def pluginsTypedReturn(tpe: Type, typer: Typer, tree: Return, pt: Type): Type = { - val annotCheckersType = adaptTypeOfReturn(tree.expr, pt, tpe) - if (analyzerPlugins.isEmpty) annotCheckersType - else analyzerPlugins.foldLeft(annotCheckersType)((tpe, plugin) => - if (!plugin.isActive()) tpe else plugin.pluginsTypedReturn(tpe, typer, tree, pt)) + def pluginsTypedReturn(tpe: Type, typer: Typer, tree: Return, pt: Type): Type = invoke(new CumulativeOp[Type] { + def default = adaptTypeOfReturn(tree.expr, pt, tpe) + def accumulate = (tpe, p) => p.pluginsTypedReturn(tpe, typer, tree, pt) + }) + + /** A list of registered macro plugins */ + private var macroPlugins: List[MacroPlugin] = Nil + + /** Registers a new macro plugin */ + def addMacroPlugin(plugin: MacroPlugin) { + if (!macroPlugins.contains(plugin)) + macroPlugins = plugin :: macroPlugins + } + + private abstract class NonCumulativeOp[T] { + def position: Position + def description: String + def default: T + def custom(plugin: MacroPlugin): Option[T] + } + + private def invoke[T](op: NonCumulativeOp[T]): T = { + if (macroPlugins.isEmpty) op.default + else { + val results = macroPlugins.filter(_.isActive()).map(plugin => (plugin, op.custom(plugin))) + results.flatMap { case (p, Some(result)) => Some((p, result)); case _ => None } match { + case (p1, _) :: (p2, _) :: _ => typer.context.error(op.position, s"both $p1 and $p2 want to ${op.description}"); op.default + case (_, custom) :: Nil => custom + case Nil => op.default + } + } + } + + /** @see MacroPlugin.pluginsTypedMacroBody */ + def pluginsTypedMacroBody(typer: Typer, ddef: DefDef): Tree = invoke(new NonCumulativeOp[Tree] { + def position = ddef.pos + def description = "typecheck this macro definition" + def default = standardTypedMacroBody(typer, ddef) + def custom(plugin: MacroPlugin) = plugin.pluginsTypedMacroBody(typer, ddef) + }) + + /** @see MacroPlugin.pluginsMacroExpand */ + def pluginsMacroExpand(typer: Typer, expandee: Tree, mode: Mode, pt: Type): Tree = invoke(new NonCumulativeOp[Tree] { + def position = expandee.pos + def description = "expand this macro application" + def default = standardMacroExpand(typer, expandee, mode, pt) + def custom(plugin: MacroPlugin) = plugin.pluginsMacroExpand(typer, expandee, mode, pt) + }) + + /** @see MacroPlugin.pluginsMacroArgs */ + def pluginsMacroArgs(typer: Typer, expandee: Tree): MacroArgs = invoke(new NonCumulativeOp[MacroArgs] { + def position = expandee.pos + def description = "compute macro arguments for this macro application" + def default = standardMacroArgs(typer, expandee) + def custom(plugin: MacroPlugin) = plugin.pluginsMacroArgs(typer, expandee) + }) + + /** @see MacroPlugin.pluginsMacroRuntime */ + def pluginsMacroRuntime(expandee: Tree): MacroRuntime = invoke(new NonCumulativeOp[MacroRuntime] { + def position = expandee.pos + def description = "compute macro runtime for this macro application" + def default = standardMacroRuntime(expandee) + def custom(plugin: MacroPlugin) = plugin.pluginsMacroRuntime(expandee) + }) + + /** @see MacroPlugin.pluginsEnterSym */ + def pluginsEnterSym(namer: Namer, tree: Tree): Context = + if (macroPlugins.isEmpty) namer.standardEnterSym(tree) + else invoke(new NonCumulativeOp[Context] { + def position = tree.pos + def description = "enter a symbol for this tree" + def default = namer.standardEnterSym(tree) + def custom(plugin: MacroPlugin) = { + val hasExistingSym = tree.symbol != NoSymbol + val result = plugin.pluginsEnterSym(namer, tree) + if (result && hasExistingSym) Some(namer.context) + else if (result && tree.isInstanceOf[Import]) Some(namer.context.make(tree)) + else if (result) Some(namer.context) + else None + } + }) + + /** @see MacroPlugin.pluginsEnsureCompanionObject */ + def pluginsEnsureCompanionObject(namer: Namer, cdef: ClassDef, creator: ClassDef => Tree = companionModuleDef(_)): Symbol = invoke(new NonCumulativeOp[Symbol] { + def position = cdef.pos + def description = "enter a companion symbol for this tree" + def default = namer.standardEnsureCompanionObject(cdef, creator) + def custom(plugin: MacroPlugin) = plugin.pluginsEnsureCompanionObject(namer, cdef, creator) + }) + + /** @see MacroPlugin.pluginsEnterStats */ + def pluginsEnterStats(typer: Typer, stats: List[Tree]): List[Tree] = { + // performance opt + if (macroPlugins.isEmpty) stats + else macroPlugins.foldLeft(stats)((current, plugin) => + if (!plugin.isActive()) current else plugin.pluginsEnterStats(typer, stats)) } } |