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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scalac.transformer;
import java.io.*;
import java.util.*;
import scalac.*;
import scalac.util.*;
import scalac.ast.*;
import scalac.symtab.*;
import Tree.*;
import scalac.typechecker.DeSugarize ;
/** (1) Make all functions into one-argument functions
* (2) Convert `def' parameters to closures
* (3) Convert matches with non-visitor arguments to postfix applications
*/
public class UnCurry extends OwnerTransformer
implements Modifiers {
UnCurryPhase descr;
public UnCurry(Global global, UnCurryPhase descr) {
super(global);
this.descr = descr;
}
/** (ps_1) ... (ps_n) => (ps_1, ..., ps_n)
*/
ValDef[][] uncurry(ValDef[][] params) {
int n = 0;
for (int i = 0; i < params.length; i++)
n = n + params[i].length;
ValDef[] ps = new ValDef[n];
int j = 0;
for (int i = 0; i < params.length; i++) {
System.arraycopy(params[i], 0, ps, j, params[i].length);
j = j + params[i].length;
}
return new ValDef[][]{ps};
}
/** tree of non-method type T ==> same tree with method type ()T
*/
Tree asMethod(Tree tree) {
switch (tree.type) {
case MethodType(_, _):
return tree;
default:
return tree.setType(Type.MethodType(Symbol.EMPTY_ARRAY, tree.type));
}
}
/** - uncurry all symbol and tree types (@see UnCurryPhase)
* - for every curried parameter list: (ps_1) ... (ps_n) ==> (ps_1, ..., ps_n)
* - for every curried application: f(args_1)...(args_n) ==> f(args_1, ..., args_n)
* - for every type application: f[Ts] ==> f[Ts]() unless followed by parameters
* - for every use of a parameterless function: f ==> f() and q.f ==> q.f()
* - for every def-parameter: def x: T ==> x: () => T
* - for every use of a def-parameter: x ==> x.apply()
* - for every argument to a def parameter `def x: T':
* if argument is not a reference to a def parameter:
* convert argument `e' to (expansion of) `() => e'
* - for every argument list that corresponds to a repeated parameter
* (a_1, ..., a_n) => (Sequence(a_1, ..., a_n))
*/
public Tree transform(Tree tree) {
//new scalac.ast.printer.TextTreePrinter().print("uncurry: ").print(tree).println().end();//DEBUG
//uncurry type and symbol
if (tree.type != null) tree.type = descr.uncurry(tree.type);
switch (tree) {
case ClassDef(_, _, AbsTypeDef[] tparams, ValDef[][] vparams, Tree tpe, Template impl):
return copy.ClassDef(
tree, tree.symbol(), tparams,
uncurry(transform(vparams, tree.symbol())),
tpe,
transform(impl, tree.symbol()));
case DefDef(_, _, AbsTypeDef[] tparams, ValDef[][] vparams, Tree tpe, Tree rhs):
Tree rhs1 = transform(rhs, tree.symbol());
return copy.DefDef(
tree, tree.symbol(), tparams,
uncurry(transform(vparams, tree.symbol())),
tpe, rhs1);
case ValDef(_, _, Tree tpe, Tree rhs):
if (tree.symbol().isDefParameter()) {
Type newtype = global.definitions.functionType(Type.EMPTY_ARRAY, tpe.type);
Tree tpe1 = gen.mkType(tpe.pos, newtype);
return copy.ValDef(tree, tpe1, rhs).setType(newtype);
} else {
return super.transform(tree);
}
case TypeApply(Tree fn, Tree[] args):
Tree tree1 = asMethod(super.transform(tree));
return gen.Apply(tree1, new Tree[0]);
case Apply(Tree fn, Tree[] args):
// f(x)(y) ==> f(x, y)
// argument to parameterless function e => ( => e)
Type ftype = fn.type;
Tree fn1 = transform(fn);
Tree[] args1 = transformArgs(tree.pos, args, ftype);
if (TreeInfo.methSymbol(fn1) == global.definitions.MATCH &&
!(args1[0] instanceof Tree.Visitor)) {
switch (TreeInfo.methPart(fn1)) {
case Select(Tree qual, Name name):
assert name == Names.match;
return gen.postfixApply(qual, args1[0], currentOwner);
default:
throw new ApplicationError("illegal prefix for match: " + tree);
}
} else {
switch (fn1) {
case Apply(Tree fn2, Tree[] args2):
Tree[] newargs = new Tree[args1.length + args2.length];
System.arraycopy(args2, 0, newargs, 0, args2.length);
System.arraycopy(args1, 0, newargs, args2.length, args1.length);
return copy.Apply(tree, fn2, newargs);
default:
return copy.Apply(tree, fn1, args1);
}
}
case Select(_, _):
case Ident(_):
if( TreeInfo.isWildcardPattern( tree ) )
return tree;
Tree tree1 = super.transform(tree);
switch (tree1.symbol().type()) {
case PolyType(Symbol[] tparams, Type restp):
if (tparams.length == 0 && !(restp instanceof Type.MethodType)) {
return gen.Apply(asMethod(tree1), new Tree[0]);
} else {
return tree1;
}
default:
if (tree1.symbol().isDefParameter()) {
tree1.type = global.definitions.functionType(
Type.EMPTY_ARRAY, tree1.type);
return gen.Apply(gen.Select(tree1, Names.apply), new Tree[0]);
} else {
return tree1;
}
}
default:
return super.transform(tree);
}
}
// java.util.HashSet visited = new java.util.HashSet();//DEBUG
/** Transform arguments `args' to method with type `methtype'.
*/
private Tree[] transformArgs(int pos, Tree[] args, Type methtype) {
// if (args.length != 0 && visited.contains(args)) {
// new scalac.ast.printer.TextTreePrinter().print("dup args: ").print(make.Block(pos, args)).println().end();//DEBUG
// assert false;
// }
// visited.add(args);//DEBUG
switch (methtype) {
case MethodType(Symbol[] params, _):
if (params.length == 1 && (params[0].flags & REPEATED) != 0) {
assert (args.length != 1 || !(args[0] instanceof Tree.Sequence));
args = new Tree[]{make.Sequence( pos, args ).setType(params[0].type())};
}
Tree[] args1 = args;
for (int i = 0; i < args.length; i++) {
Tree arg = args[i];
Tree arg1 = transformArg(arg, params[i]);
if (arg1 != arg && args1 == args) {
args1 = new Tree[args.length];
System.arraycopy(args, 0, args1, 0, i);
}
args1[i] = arg1;
}
return args1;
case PolyType(_, Type restp):
return transformArgs(pos, args, restp);
default:
if (args.length == 0) return args; // could be arguments of nullary case pattern
else throw new ApplicationError(methtype);
}
}
/** for every argument to a def parameter `def x: T':
* if argument is not a reference to a def parameter:
* convert argument `e' to (expansion of) `() => e'
*/
private Tree transformArg(Tree arg, Symbol formal) {
if ((formal.flags & DEF) != 0) {
Symbol sym = arg.symbol();
if (sym != null && (sym.flags & DEF) != 0) {
Tree arg1 = transform(arg);
switch (arg1) {
case Apply(Select(Tree qual, Name name), Tree[] args1):
assert name == Names.apply && args1.length == 0;
return qual;
default:
global.debugPrinter.print(arg1).flush();//debug
throw new ApplicationError();
}
}
return transform(
gen.mkUnitFunction(arg, descr.uncurry(arg.type), currentOwner));
} else {
return transform(arg);
}
}
}
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