1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
package scala.reflect.reify
import scala.reflect.makro.{ReificationError, UnexpectedReificationError}
import scala.reflect.makro.runtime.Context
abstract class Taggers {
val c: Context
import c.universe._
import definitions._
val coreTags = Map(
ByteClass.asType -> newTermName("Byte"),
ShortClass.asType -> newTermName("Short"),
CharClass.asType -> newTermName("Char"),
IntClass.asType -> newTermName("Int"),
LongClass.asType -> newTermName("Long"),
FloatClass.asType -> newTermName("Float"),
DoubleClass.asType -> newTermName("Double"),
BooleanClass.asType -> newTermName("Boolean"),
UnitClass.asType -> newTermName("Unit"),
AnyClass.asType -> newTermName("Any"),
ObjectClass.asType -> newTermName("Object"),
NothingClass.asType -> newTermName("Nothing"),
NullClass.asType -> newTermName("Null"),
StringClass.asType -> newTermName("String"))
// todo. the following two methods won't be necessary once we implement implicit macro generators for tags
def materializeArrayTag(prefix: Tree, tpe: Type): Tree =
materializeClassTag(prefix, tpe)
def materializeClassTag(prefix: Tree, tpe: Type): Tree =
materializeTag(prefix, tpe, ClassTagModule, {
val runtimeClass = c.reifyRuntimeClass(tpe, concrete = true)
val factory = TypeApply(Select(Ident(ClassTagModule), "apply"), List(TypeTree(tpe)))
Apply(factory, List(runtimeClass))
})
def materializeTypeTag(prefix: Tree, tpe: Type, concrete: Boolean): Tree = {
val tagModule = if (concrete) ConcreteTypeTagModule else TypeTagModule
materializeTag(prefix, tpe, tagModule, c.reifyType(prefix, tpe, dontSpliceAtTopLevel = true, concrete = concrete))
}
private def materializeTag(prefix: Tree, tpe: Type, tagModule: Symbol, materializer: => Tree): Tree = {
val result =
tpe match {
case coreTpe if coreTags contains coreTpe =>
val ref = if (tagModule.owner.isPackageClass) Ident(tagModule) else Select(prefix, tagModule.name)
Select(ref, coreTags(coreTpe))
case _ =>
translatingReificationErrors(materializer)
}
try c.typeCheck(result)
catch { case terr @ c.TypeError(pos, msg) => failTag(result, terr) }
}
def materializeExpr(prefix: Tree, expr: Tree): Tree = {
val result = translatingReificationErrors(c.reifyTree(prefix, expr))
try c.typeCheck(result)
catch { case terr @ c.TypeError(pos, msg) => failExpr(result, terr) }
}
private def translatingReificationErrors(materializer: => Tree): Tree = {
try materializer
catch {
case ReificationError(pos, msg) =>
c.error(pos.asInstanceOf[c.Position], msg) // this cast is a very small price for the sanity of exception handling
EmptyTree
case UnexpectedReificationError(pos, err, cause) if cause != null =>
throw cause
}
}
private def failTag(result: Tree, reason: Any): Nothing = {
val Apply(TypeApply(fun, List(tpeTree)), _) = c.macroApplication
val tpe = tpeTree.tpe
val PolyType(_, MethodType(_, tagTpe)) = fun.tpe
val tagModule = tagTpe.typeSymbol.companionSymbol
if (c.compilerSettings.contains("-Xlog-implicits"))
c.echo(c.enclosingPosition, s"cannot materialize ${tagModule.name}[$tpe] as $result because:\n$reason")
c.abort(c.enclosingPosition, "No %s available for %s".format(tagModule.name, tpe))
}
private def failExpr(result: Tree, reason: Any): Nothing = {
val Apply(_, expr :: Nil) = c.macroApplication
c.abort(c.enclosingPosition, s"Cannot materialize $expr as $result because:\n$reason")
}
}
|
