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Compiler for the SubScript extension of the Scala Programming Language
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/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
*
* @author Paul Phillips
*/
package scala.tools.nsc
package ast
import symtab.Flags
import scala.language.implicitConversions
/** A DSL for generating scala code. The goal is that the
* code generating code should look a lot like the code it
* generates.
*/
trait TreeDSL {
val global: Global
import global._
import definitions._
object CODE {
// Add a null check to a Tree => Tree function
def nullSafe[T](f: Tree => Tree, ifNull: Tree): Tree => Tree =
tree => IF (tree MEMBER_== NULL) THEN ifNull ELSE f(tree)
def returning[T](x: T)(f: T => Unit): T = util.returning(x)(f)
object LIT extends (Any => Literal) {
def typed(x: Any) = apply(x) setType ConstantType(Constant(x))
def apply(x: Any) = Literal(Constant(x))
}
// Boring, predictable trees.
def TRUE = LIT typed true
def FALSE = LIT typed false
def ZERO = LIT(0)
def NULL = LIT(null)
def UNIT = LIT(())
def fn(lhs: Tree, op: Name, args: Tree*) = Apply(Select(lhs, op), args.toList)
def fn(lhs: Tree, op: Symbol, args: Tree*) = Apply(Select(lhs, op), args.toList)
class TreeMethods(target: Tree) {
/** logical/comparison ops **/
def OR(other: Tree) =
if (target == EmptyTree) other
else if (other == EmptyTree) target
else gen.mkOr(target, other)
def AND(other: Tree) =
if (target == EmptyTree) other
else if (other == EmptyTree) target
else gen.mkAnd(target, other)
/** Note - calling ANY_== in the matcher caused primitives to get boxed
* for the comparison, whereas looking up nme.EQ does not. See #3570 for
* an example of how target.tpe can be non-null, yet it claims not to have
* a member called nme.EQ. Not sure if that should happen, but we can be
* robust by dragging in Any regardless.
*/
def MEMBER_== (other: Tree) = {
val opSym = if (target.tpe == null) NoSymbol else target.tpe member nme.EQ
if (opSym == NoSymbol) ANY_==(other)
else fn(target, opSym, other)
}
def ANY_EQ (other: Tree) = OBJ_EQ(other AS ObjectTpe)
def ANY_== (other: Tree) = fn(target, Any_==, other)
def ANY_!= (other: Tree) = fn(target, Any_!=, other)
def OBJ_EQ (other: Tree) = fn(target, Object_eq, other)
def OBJ_NE (other: Tree) = fn(target, Object_ne, other)
def INT_>= (other: Tree) = fn(target, getMember(IntClass, nme.GE), other)
def INT_== (other: Tree) = fn(target, getMember(IntClass, nme.EQ), other)
def INT_- (other: Tree) = fn(target, getMember(IntClass, nme.MINUS), other)
// generic operations on ByteClass, IntClass, LongClass
def GEN_| (other: Tree, kind: ClassSymbol) = fn(target, getMember(kind, nme.OR), other)
def GEN_& (other: Tree, kind: ClassSymbol) = fn(target, getMember(kind, nme.AND), other)
def GEN_== (other: Tree, kind: ClassSymbol) = fn(target, getMember(kind, nme.EQ), other)
def GEN_!= (other: Tree, kind: ClassSymbol) = fn(target, getMember(kind, nme.NE), other)
/** Apply, Select, Match **/
def APPLY(params: Tree*) = Apply(target, params.toList)
def APPLY(params: List[Tree]) = Apply(target, params)
def DOT(member: Name) = SelectStart(Select(target, member))
def DOT(sym: Symbol) = SelectStart(Select(target, sym))
/** Assignment */
// !!! This method is responsible for some tree sharing, but a diligent
// reviewer pointed out that we shouldn't blindly duplicate these trees
// as there might be DefTrees nested beneath them. It's not entirely
// clear how to proceed, so for now it retains the non-duplicating behavior.
def ===(rhs: Tree) = Assign(target, rhs)
/** Casting & type tests -- working our way toward understanding exactly
* what differs between the different forms of IS and AS.
*
* See ticket #2168 for one illustration of AS vs. AS_ANY.
*/
def AS(tpe: Type) = gen.mkAsInstanceOf(target, tpe, any = true, wrapInApply = false)
def IS_OBJ(tpe: Type) = gen.mkIsInstanceOf(target, tpe, any = false)
def GETCLASS() = fn(target, Object_getClass)
}
case class SelectStart(tree: Select) {
def apply(args: Tree*) = Apply(tree, args.toList)
}
class CaseStart(pat: Tree, guard: Tree) {
def IF(g: Tree): CaseStart = new CaseStart(pat, g)
def ==>(body: Tree): CaseDef = CaseDef(pat, guard, body)
}
class IfStart(cond: Tree, thenp: Tree) {
def THEN(x: Tree) = new IfStart(cond, x)
def ELSE(elsep: Tree) = If(cond, thenp, elsep)
def ENDIF = If(cond, thenp, EmptyTree)
}
class TryStart(body: Tree, catches: List[CaseDef], fin: Tree) {
def CATCH(xs: CaseDef*) = new TryStart(body, xs.toList, fin)
def ENDTRY = Try(body, catches, fin)
}
def CASE(pat: Tree): CaseStart = new CaseStart(pat, EmptyTree)
def DEFAULT: CaseStart = new CaseStart(Ident(nme.WILDCARD), EmptyTree)
def NEW(tpt: Tree, args: Tree*): Tree = New(tpt, List(args.toList))
def NOT(tree: Tree) = Select(tree, Boolean_not)
def AND(guards: Tree*) = if (guards.isEmpty) EmptyTree else guards reduceLeft gen.mkAnd
def IF(tree: Tree) = new IfStart(tree, EmptyTree)
def TRY(tree: Tree) = new TryStart(tree, Nil, EmptyTree)
def BLOCK(xs: Tree*) = Block(xs.init.toList, xs.last)
def SOME(xs: Tree*) = Apply(SomeClass.companionSymbol, gen.mkTuple(xs.toList))
/** Typed trees from symbols. */
def REF(sym: Symbol) = gen.mkAttributedRef(sym)
def REF(pre: Type, sym: Symbol) = gen.mkAttributedRef(pre, sym)
/** Implicits - some of these should probably disappear **/
implicit def mkTreeMethods(target: Tree): TreeMethods = new TreeMethods(target)
implicit def mkTreeMethodsFromSymbol(target: Symbol): TreeMethods = new TreeMethods(Ident(target))
/** (foo DOT bar) might be simply a Select, but more likely it is to be immediately
* followed by an Apply. We don't want to add an actual apply method to arbitrary
* trees, so SelectStart is created with an apply - and if apply is not the next
* thing called, the implicit from SelectStart -> Tree will provide the tree.
*/
implicit def mkTreeFromSelectStart(ss: SelectStart): Select = ss.tree
implicit def mkTreeMethodsFromSelectStart(ss: SelectStart): TreeMethods = mkTreeMethods(ss.tree)
}
}