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/* NSC -- new scala compiler
* Copyright 2005 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.ast;
import symtab.Flags._;
abstract class TreeInfo {
val global: Global;
import global._;
def isTerm(tree: Tree): boolean = tree.isTerm;
def isType(tree: Tree): boolean = tree.isType;
def isOwnerDefinition(tree: Tree): boolean = tree match {
case PackageDef(_, _)
| ClassDef(_, _, _, _, _)
| ModuleDef(_, _, _)
| DefDef(_, _, _, _, _, _)
| Import(_, _) => true
case _ => false
}
def isDefinition(tree: Tree): boolean = tree.isDef;
def isDeclaration(tree: Tree): boolean = tree match {
case DefDef(_, _, _, _, _, EmptyTree)
| ValDef(_, _, _, EmptyTree)
| AbsTypeDef(_, _, _, _)
| AliasTypeDef(_, _, _, _) => true
case _ => false
}
/** Is tree legal as a member definition of an interface?
*/
def isInterfaceMember(tree: Tree): boolean = tree match {
case EmptyTree => true
case Import(_, _) => true
case AbsTypeDef(_, _, _, _) => true
case AliasTypeDef(_, _, _, _) => true
case DefDef(mods, _, _, _, _, __) => mods.hasFlag(DEFERRED)
case ValDef(mods, _, _, _) => mods.hasFlag(DEFERRED)
case DocDef(_, definition) => isInterfaceMember(definition)
case Attributed(_, definition) => isInterfaceMember(definition)
case _ => false
}
/** Is tree a pure definition?
*/
def isPureDef(tree: Tree): boolean = tree match {
case EmptyTree
| ClassDef(_, _, _, _, _)
| ModuleDef(_, _, _)
| AbsTypeDef(_, _, _, _)
| AliasTypeDef(_, _, _, _)
| Import(_, _)
| DefDef(_, _, _, _, _, _) =>
true
case ValDef(mods, _, _, rhs) =>
mods.hasFlag(MUTABLE) && isPureExpr(rhs)
case DocDef(_, definition) =>
isPureDef(definition)
case Attributed(_, definition) =>
isPureDef(definition)
case _ =>
false
}
/** Is tree a stable & pure expression?
*/
def isPureExpr(tree: Tree): boolean = tree match {
case EmptyTree
| This(_)
| Super(_, _)
| Literal(_) =>
true
case Ident(_) =>
tree.symbol.isStable
case Select(qual, _) =>
tree.symbol.isStable && isPureExpr(qual)
case TypeApply(fn, _) =>
isPureExpr(fn)
case Apply(fn, List()) =>
isPureExpr(fn)
case Typed(expr, _) =>
isPureExpr(expr)
case Block(stats, expr) =>
(stats forall isPureDef) && isPureExpr(expr)
case _ =>
false
}
/** Is tree a self constructor call?
*/
def isSelfConstrCall(tree: Tree): boolean = tree match {
case Ident(nme.CONSTRUCTOR) =>
true
case TypeApply(constr, _) =>
isSelfConstrCall(constr)
case Apply(constr, _) =>
isSelfConstrCall(constr)
case _ =>
false
}
/** Is tree a variable pattern */
def isVarPattern(pat: Tree): boolean = pat match {
case Ident(name) => isVariableName(name)
case _ => false
}
/** The longest statement suffix that starts with a constructor */
def firstConstructor(stats: List[Tree]): Tree = stats.head match {
case constr @ DefDef(_, nme.CONSTRUCTOR, _, _, _, _) => constr
case _ => firstConstructor(stats.tail)
}
/** Is name a left-associative operator? */
def isLeftAssoc(operator: Name): boolean =
operator.length > 0 && operator(operator.length - 1) != ':';
/** Is name a variable name? */
def isVariableName(name: Name): boolean = {
val first = name(0);
((('a' <= first && first <= 'z') || first == '_')
&& name != nme.false_
&& name != nme.true_
&& name != nme.null_)
}
/** Is tree a this node which belongs to `enclClass'? */
def isSelf(tree: Tree, enclClass: Symbol): boolean = tree match {
case This(_) => tree.symbol == enclClass
case _ => false
}
/** Is this pattern node a catch-all (wildcard or variable) pattern? */
def isDefaultCase(cdef: CaseDef) = cdef match {
case CaseDef(Ident(nme.WILDCARD), EmptyTree, _) => true
case CaseDef(Bind(_, Ident(nme.WILDCARD)), EmptyTree, _) => true
case _ => false
}
/** Is this pattern node a catch-all or type-test pattern? */
def isCatchCase(cdef: CaseDef) = cdef match {
case CaseDef(Typed(Ident(nme.WILDCARD), tpt), EmptyTree, _) => isSimple(tpt.tpe)
case CaseDef(Bind(_, Typed(Ident(nme.WILDCARD), tpt)), EmptyTree, _) => isSimple(tpt.tpe)
case _ => isDefaultCase(cdef)
}
private def isSimple(tp: Type): boolean = true;
/* If we have run-time types, and these are used for pattern matching,
we should replace this by something like:
tp match {
case TypeRef(pre, sym, args) =>
args.isEmpty && (sym.owner.isPackageClass || isSimple(pre))
case NoPrefix =>
true
case _ =>
false
}
*/
/** Is this pattern node a sequence-valued pattern? */
def isSequenceValued(tree: Tree): boolean = tree match {
case Bind(_, body) => isSequenceValued(body)
case Sequence(_) => true
case ArrayValue(_, _) => true
case Star(_) => true
case Alternative(ts) => ts exists isSequenceValued
case _ => false
}
/** The method part of an application node
*/
def methPart(tree: Tree): Tree = tree match {
case Apply(fn, _) => methPart(fn)
case TypeApply(fn, _) => methPart(fn)
case AppliedTypeTree(fn, _) => methPart(fn)
case _ => tree
}
}
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