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added Iterator.flatten method; refactoring: clo...
added Iterator.flatten method; refactoring: closure -> baseTypeSeq
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| /* NSC -- new Scala compiler | ||
| * Copyright 2005-2008 LAMP/EPFL | ||
| * @author Martin Odersky | ||
| */ | ||
| package scala.tools.nsc.symtab | ||
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| import scala.collection.mutable.ListBuffer | ||
| import util.BitSet | ||
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| /** A base type sequence (BaseTypeSeq) is an ordered sequence spanning all the base types | ||
| * of a type. It characterized by the following two laws: | ||
| * | ||
| * (1) Each element of `tp.baseTypeSeq' is a basetype of `tp' | ||
| * (2) For each basetype `bt1' of `tp' there is an element `bt' in `tp.baseTypeSeq' such that | ||
| * | ||
| * bt.typeSymbol = bt1.typeSymbol | ||
| * bt <: bt1 | ||
| * | ||
| * (3) The type symbols of different elements are different. | ||
| * | ||
| * Elements in the sequence are ordered by Symbol.isLess. | ||
| * @note base type sequences were called closures up to 2.7.1. The name has been changed | ||
| * to avoid confusion with function closures. | ||
| */ | ||
| trait BaseTypeSeqs { | ||
| self: SymbolTable => | ||
| import definitions._ | ||
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| class BaseTypeSeq(elems: Array[Type]) { | ||
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| /** The number of types in the sequence */ | ||
| def length: Int = elems.length | ||
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| /** The type at i'th position in this sequence; lazy types are returned evaluated. */ | ||
| def apply(i: Int): Type = elems(i) | ||
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| /** The type symbol of the type at i'th position in this sequence; | ||
| * no evaluation needed. | ||
| */ | ||
| def typeSymbol(i: Int): Symbol = elems(i).typeSymbol | ||
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| /** Return all evaluated types in this sequence as a list */ | ||
| def toList: List[Type] = elems.toList | ||
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| private def copy(head: Type, offset: Int): BaseTypeSeq = { | ||
| val arr = new Array[Type](elems.length + offset) | ||
| Array.copy(elems, 0, arr, offset, elems.length) | ||
| arr(0) = head | ||
| new BaseTypeSeq(arr) | ||
| } | ||
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| /** Compute new base type sequence with `tp' prepended to this sequence */ | ||
| def prepend(tp: Type): BaseTypeSeq = copy(tp, 1) | ||
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| /** Compute new base type sequence with `tp' replacing the head of this sequence */ | ||
| def updateHead(tp: Type): BaseTypeSeq = copy(tp, 0) | ||
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| /** Compute new base type sequence where every element is mapped | ||
| * with function `f'. Lazy types are mapped but not evaluated */ | ||
| def map(f: Type => Type): BaseTypeSeq = new BaseTypeSeq(elems map f) | ||
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| def exists(p: Type => Boolean): Boolean = elems exists p | ||
| // (0 until length) exists (i => p(this(i))) | ||
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| lazy val maxDepth: Int = { | ||
| var d = 0 | ||
| for (i <- 0 until length) d = Math.max(d, self.maxDepth(this(i))) | ||
| d | ||
| } | ||
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| override def toString = elems.mkString("BTS(", ",", ")") | ||
| } | ||
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| /** A merker object for a base type sequence that's no yet computed. | ||
| * used to catch inheritance cycles | ||
| */ | ||
| val undetBaseTypeSeq: BaseTypeSeq = new BaseTypeSeq(Array()) | ||
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| /** Create a base type sequence consisting of a single type */ | ||
| def baseTypeSingletonSeq(tp: Type): BaseTypeSeq = new BaseTypeSeq(Array(tp)) | ||
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| /** Create the base type sequence of a compound type wuth given tp.parents */ | ||
| def compoundBaseTypeSeq(tp: CompoundType): BaseTypeSeq = { | ||
| //Console.println("computing baseTypeSeq of " + tsym.tpe + " " + tp.parents)//DEBUG | ||
| val buf = new ListBuffer[Type] | ||
| buf += tp.typeSymbol.tpe | ||
| var btsSize = 1 | ||
| val nparents = tp.parents.length | ||
| if (nparents != 0) { | ||
| val pbtss = new Array[BaseTypeSeq](nparents) | ||
| val index = new Array[Int](nparents) | ||
| var i = 0 | ||
| for (p <- tp.parents) { | ||
| pbtss(i) = | ||
| if (p.baseTypeSeq eq undetBaseTypeSeq) AnyClass.info.baseTypeSeq | ||
| else p.baseTypeSeq | ||
| index(i) = 0 | ||
| i += 1 | ||
| } | ||
| def nextBaseType(i: Int): Type = { | ||
| val j = index(i) | ||
| val pbts = pbtss(i) | ||
| if (j < pbts.length) pbts(j) else AnyClass.tpe | ||
| } | ||
| var minSym: Symbol = NoSymbol | ||
| while (minSym != AnyClass) { | ||
| minSym = nextBaseType(0).typeSymbol | ||
| i = 1 | ||
| while (i < nparents) { | ||
| if (nextBaseType(i).typeSymbol isLess minSym) | ||
| minSym = nextBaseType(i).typeSymbol | ||
| i += 1 | ||
| } | ||
| var minTypes: List[Type] = List() | ||
| i = 0 | ||
| while (i < nparents) { | ||
| val tp = nextBaseType(i) | ||
| if (tp.typeSymbol == minSym) { | ||
| if (!(minTypes exists (tp =:=))) minTypes = tp :: minTypes; | ||
| index(i) = index(i) + 1 | ||
| } | ||
| i += 1 | ||
| } | ||
| buf += intersectionType(minTypes) | ||
| btsSize += 1 | ||
| } | ||
| } | ||
| val elems = new Array[Type](btsSize) | ||
| buf.copyToArray(elems, 0) | ||
| //Console.println("baseTypeSeqCache of " + tsym.tpe + " = " + arr.toString)//DEBUG | ||
| tp.baseTypeSeqCache = new BaseTypeSeq(elems) | ||
| var j = 0 | ||
| while (j < btsSize) { | ||
| elems(j) match { | ||
| case RefinedType(variants, decls) => | ||
| // can't assert decls.isEmpty; see t0764 | ||
| //if (!decls.isEmpty) assert(false, "computing closure of "+this+":"+this.isInstanceOf[RefinedType]+"/"+closureCache(j)) | ||
| //Console.println("compute closure of "+this+" => glb("+variants+")") | ||
| elems(j) = mergePrefixAndArgs(variants, -1, maxBaseTypeSeqDepth(variants) + LubGlbMargin) match { | ||
| case Some(tp0) => tp0 | ||
| case None => throw new TypeError( | ||
| "the type intersection "+(tp.parents mkString " with ")+" is malformed"+ | ||
| "\n --- because ---"+ | ||
| "\n no common type instance of base types "+(variants mkString ", and ")+" exists.") | ||
| } | ||
| case _ => | ||
| } | ||
| j += 1 | ||
| } | ||
| tp.baseTypeSeqCache // todo: needed, or can be unit? | ||
| } | ||
| } |
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