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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
|
/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scalac.ast;
import java.io.*;
import java.util.*;
import scalac.*;
import scalac.symtab.*;
import scalac.typechecker.Infer;
import scalac.util.*;
import Tree.*;
/** A helper class for building trees
*
* @author Martin Odersky, Christine Roeckl
* @version 1.0
*/
public class TreeGen implements Kinds, Modifiers {
/********************************************************************************/
/********************************************************************************/
/** VARIABLES **/
/** the global environment
*/
protected Global global;
/** the global definitions
*/
protected Definitions definitions;
/** the tree factory
*/
public TreeFactory make;
/** the type inferencer
*/
Infer infer;
/************************************************************************/
/************************************************************************/
/** CONSTRUCTORS **/
public TreeGen(Global global, TreeFactory make) {
this.global = global;
this.definitions = global.definitions;
this.make = make;
this.infer = new Infer(global, this, make);
}
public TreeGen(Global global) {
this(global, global.make);
}
/*************************************************************************/
/*************************************************************************/
/** METHODS **/
public Type deref(Type tp) {
switch (tp) {
case PolyType(Symbol[] tparams, Type restp):
if (tparams.length == 0) return restp;
}
return tp;
}
/** Create a dummy symbol to be used for templates.
*/
public Symbol localDummy(int pos, Symbol owner) {
return new TermSymbol(pos, Name.EMPTY, owner, 0)
.setInfo(Type.NoType);
}
public Tree mkStable(Tree tree) {
Symbol sym = tree.symbol();
if (sym.isStable()) {
switch (tree) {
case Ident(_):
tree.setType(Type.singleType(sym.owner().thisType(), sym));
break;
case Select(Tree qual, _):
if (qual.type.isStable())
tree.setType(Type.singleType(qual.type, sym));
}
}
return tree;
}
public Tree mkRef(int pos, Type pre, Symbol sym) {
if (pre.isSameAs(Type.localThisType) || pre.symbol().isRoot())
return Ident(pos, sym);
else
return Select(pos, mkStableId(pos, pre), sym);
}
public Tree mkRef(int pos, Symbol sym) {
return mkRef(pos, sym.owner().thisType(), sym);
}
/** Build and attribute stable identifier tree corresponding to given prefix.
*/
public Tree mkStableId(int pos, Type pre) {
switch (pre.expandModuleThis()) {
case ThisType(Symbol sym):
return make.This(pos, Ident(pos, sym)).setType(pre);
case SingleType(Type pre1, Symbol sym):
return mkStable(mkRef(pos, pre1, sym));
default:
throw new ApplicationError();
}
}
/** Build and attribute tree corresponding to given type.
*/
public Tree mkType(int pos, Type type) {
return TypeTerm(pos, type);
}
/** Build and attribute tree array corresponding to given type array.
*/
public Tree[] mkTypes(int pos, Type[] types) {
Tree[] res = new Tree[types.length];
for (int i = 0; i < types.length; i++) {
res[i] = mkType(pos, types[i]);
}
return res;
}
/** Build and attribute tree corresponding to given type.
*/
public Tree TypeTerm(int pos, Type type) {
return make.TypeTerm(pos).setType(type);
}
/** Build and attribute tree corresponding to symbol's declaration.
*/
public Tree mkDef(int pos, Symbol sym) {
switch (sym.kind) {
case ERROR:
return make.Bad(pos).setSymbol(Symbol.ERROR).setType(Type.ErrorType);
case TYPE: case ALIAS:
return TypeDef(pos, sym);
case VAL:
if (sym.isMethod()) return DefDef(pos, sym, Tree.Empty);
else return Param(pos, sym);
default:
throw new ApplicationError();
}
}
/** Build and attribute tree array corresponding to given symbol's declarations.
*/
public Tree[] mkDefs(int pos, Symbol[] syms) {
Tree[] res = new Tree[syms.length];
for (int i = 0; i < syms.length; i++) {
res[i] = mkDef(pos, syms[i]);
}
return res;
}
/** Build a boolean constant tree.
*/
public Tree mkBooleanLit(int pos, boolean bool) {
return make.Literal(pos, bool ? Boolean.TRUE : Boolean.FALSE).
setType(definitions.BOOLEAN_TYPE);
}
/** Build a string literal
*/
public Tree mkStringLit(int pos, String str) {
return make.Literal(pos, str).setType(definitions.JAVA_STRING_TYPE);
}
/** Build an integer literal
*/
public Tree mkIntLit(int pos, int value) {
return make.Literal(pos, new Integer(value)).setType(definitions.INT_TYPE);
}
/** Build a tree to be used as a base class constructor for a template.
*/
public Tree mkParentConstr(int pos, Type parentType, Tree[] parentArgs) {
switch (parentType) {
case TypeRef(Type pre, Symbol sym, Type[] args):
Tree ref = mkRef(pos, pre, sym.constructor());
Tree constr = (args.length == 0) ? ref
: TypeApply(ref, mkTypes(sym.pos, args));
return Apply(constr, parentArgs);
default:
throw global.fail("invalid parent type", parentType);
}
}
public Tree mkParentConstr(int pos, Type parentType) {
return mkParentConstr(pos, parentType, Tree.EMPTY_ARRAY);
}
/** Build an array of trees to be used as base classes for a template.
*/
public Tree[] mkParentConstrs(int pos, Type[] parents, Tree[][] parentArgs) {
Tree[] constrs = new Tree[parents.length];
for (int i = 0; i < parents.length; ++i)
constrs[i] = (parentArgs == null ?
mkParentConstr(pos, parents[i])
: mkParentConstr(pos, parents[i], parentArgs[i]));
return constrs;
}
public Tree[] mkParentConstrs(int pos, Type[] parents) {
return mkParentConstrs(pos, parents, null);
}
/** Build parameter sections corresponding to type.
*/
public ValDef[][] mkParams(int pos, Type type) {
switch (type) {
case PolyType(Symbol[] tparams, Type restype):
return mkParams(pos, restype);
case MethodType(Symbol[] vparams, Type restype):
ValDef[] params1 = mkParams(pos, vparams);
ValDef[][] paramss = mkParams(pos, restype);
if (paramss.length == 0) {
return new ValDef[][]{params1};
} else {
ValDef[][] paramss1 = new ValDef[paramss.length + 1][];
paramss1[0] = params1;
System.arraycopy(paramss, 0, paramss1, 1, paramss.length);
return paramss1;
}
default:
return new ValDef[][]{};
}
}
/** Build parameter section corresponding to given array of symbols .
*/
public ValDef[] mkParams(int pos, Symbol[] symbols) {
ValDef[] res = new ValDef[symbols.length];
for (int i = 0; i < symbols.length; i++) {
res[i] = Param(pos, symbols[i]);
}
return res;
}
/** Build type parameter section corresponding to given array of symbols .
*/
public TypeDef[] mkTypeParams(int pos, Symbol[] symbols) {
TypeDef[] res = new TypeDef[symbols.length];
for (int i = 0; i < symbols.length; i++) {
res[i] = (TypeDef)TypeDef(pos, symbols[i]);
}
return res;
}
/** Build type definition corresponding to given symbol .
*/
public TypeDef TypeDef(int pos, Symbol sym) {
Global.instance.nextPhase();
Type symtype = sym.info();
Global.instance.prevPhase();
return (TypeDef) make.TypeDef(
pos,
sym.flags & SOURCEFLAGS,
sym.name,
TypeTerm(pos, symtype),
TypeTerm(pos, sym.loBound()))
.setSymbol(sym).setType(definitions.UNIT_TYPE);
}
public TypeDef TypeDef(Symbol sym) {
return TypeDef(sym.pos, sym);
}
/** Build parameter
*/
public ValDef Param(int pos, Symbol sym) {
global.log("use of obsolete Param method in TreeGen");
return (ValDef)ValDef(pos, sym, Tree.Empty);
}
public ValDef Param(Symbol sym) {
global.log("use of obsolete Param method in TreeGen");
return Param(sym.pos, sym);
}
public ValDef ValDef(int pos, Symbol sym) {
return (ValDef)ValDef(pos, sym, Tree.Empty);
}
public ValDef ValDef(Symbol sym) {
return Param(sym.pos, sym);
}
/** Build and attribute block with given statements, starting
* at given position. The type is the type of the last
* statement in the block.
*/
public Tree Block(int pos, Tree[] stats) {
Type tp = (stats.length == 0) ? definitions.UNIT_TYPE
: stats[stats.length - 1].type;
return make.Block(pos, stats).setType(tp);
}
/** Build and attribute non-empty block with given statements.
*/
public Tree Block(Tree[] stats) {
return Block(stats[0].pos, stats);
}
public Tree Typed(Tree tree, Type tp) {
return make.Typed(tree.pos, tree, TypeTerm(tree.pos, tp)).setType(tp);
}
/** Build and attribute the assignment lhs = rhs
*/
public Tree Assign(int pos, Tree lhs, Tree rhs) {
return make.Assign(pos, lhs, rhs).setType(definitions.UNIT_TYPE);
}
public Tree Assign(Tree lhs, Tree rhs) {
return Assign(lhs.pos, lhs, rhs);
}
/** Build and attribute new B, given constructor expression B.
*/
public Tree New(Tree constr) {
Template templ = make.Template(
constr.pos, new Tree[]{constr}, Tree.EMPTY_ARRAY);
templ.setType(constr.type);
templ.setSymbol(localDummy(constr.pos, Symbol.NONE));
return make.New(constr.pos, templ).setType(constr.type); }
/** Build an allocation new P.C[TARGS](ARGS)
* given a (singleton) type P, class C, type arguments TARGS and arguments ARGS
*/
public Tree New(int pos, Type pre, Symbol clazz,
Type[] targs, Tree[] args) {
Tree constr = mkRef(pos, pre, clazz.constructor());
if (targs.length != 0)
constr = TypeApply(constr, mkTypes(pos, targs));
Tree base = Apply(constr, args);
return New(base);
}
/** Build a monomorphic allocation new P.C(ARGS)
* given a prefix P, class C and arguments ARGS
*/
public Tree New(int pos, Type pre, Symbol clazz, Tree[] args) {
return New(pos, pre, clazz, Type.EMPTY_ARRAY, args);
}
/** Build and attribute application node with given function
* and argument trees.
*/
public Tree Apply(int pos, Tree fn, Tree[] args) {
try {
switch (fn.type) {
case Type.OverloadedType(Symbol[] alts, Type[] alttypes):
infer.methodAlternative(fn, alts, alttypes,
Tree.typeOf(args), Type.AnyType);
}
switch (fn.type) {
case Type.MethodType(Symbol[] vparams, Type restpe):
return make.Apply(pos, fn, args).setType(restpe);
}
} catch (Type.Error ex) {
}
throw new ApplicationError("method type required", fn.type);
}
public Tree Apply(Tree fn, Tree[] args) {
return Apply(fn.pos, fn, args);
}
/** Build and attribute type application node with given function
* and argument trees.
*/
public Tree TypeApply(int pos, Tree fn, Tree[] args) {
try {
switch (fn.type) {
case Type.OverloadedType(Symbol[] alts, Type[] alttypes):
infer.polyAlternative(fn, alts, alttypes, args.length);
}
switch (fn.type) {
case Type.PolyType(Symbol[] tparams, Type restpe):
return make.TypeApply(pos, fn, args)
.setType(restpe.subst(tparams, Tree.typeOf(args)));
}
} catch (Type.Error ex) {
}
throw new ApplicationError("poly type required", fn.type);
}
public Tree TypeApply(Tree fn, Tree[] args) {
return TypeApply(fn.pos, fn, args);
}
public Tree If(int pos, Tree cond, Tree thenpart, Tree elsepart) {
return
make.If(pos, cond, thenpart, elsepart).setType(thenpart.type);
}
public Tree If(Tree cond, Tree thenpart, Tree elsepart) {
return If(cond.pos, cond, thenpart, elsepart);
}
/** Build and applied type node with given function
* and argument trees.
public Tree AppliedType(int pos, Tree fn, Tree[] args) {
return make.AppliedType(pos, fn, args)
.setType(Type.appliedType(fn.type, Tree.typeOf(args)));
}
public Tree AppliedType(Tree fn, Tree[] args) {
return AppliedType(fn.pos, fn, args);
}
*/
/** Build and attribute select node of given symbol.
* It is assumed that the prefix is not empty.
*/
public Tree Select(int pos, Tree qual, Symbol sym) {
assert sym.kind != NONE;
Global.instance.nextPhase();
Type symtype = qual.type.memberType(sym);
Global.instance.prevPhase();
return make.Select(pos, qual, sym.name)
.setSymbol(sym).setType(deref(symtype));
}
public Tree Select(Tree qual, Symbol sym) {
return Select(qual.pos, qual, sym);
}
public Tree Select(Tree qual, Name name) {
Symbol sym = qual.type.lookup(name);
assert (sym.kind != NONE && sym != Symbol.ERROR) : name + " from " + qual.type;
return Select(qual, sym);
}
/** Build and attribute ident node with given symbol.
*/
public Tree Ident(int pos, Symbol sym) {
Global.instance.nextPhase();
Type symtype = sym.type();
Global.instance.prevPhase();
return make.Ident(pos, sym.name)
.setSymbol(sym).setType(deref(symtype));
}
public Tree Ident(Symbol sym) {
return Ident(sym.pos, sym);
}
/** Build and attribute this node with given symbol.
*/
public Tree This(int pos, Symbol sym) {
return make.This(pos, Ident(pos, sym)).setType(sym.thisType());
}
/** Build and attribute super node with given type.
*/
public Tree Super(int pos, Type type) {
return make.Super(pos, TypeTerm(pos, type)).setType(type);
}
/** Build and attribute value/variable/let definition node whose signature
* corresponds to given symbol and which has given rhs.
*/
public Tree ValDef(int pos, Symbol sym, Tree rhs) {
Global.instance.nextPhase();
Type symtype = sym.type();
Global.instance.prevPhase();
return make.ValDef(pos,
sym.flags & SOURCEFLAGS,
sym.name,
TypeTerm(pos, symtype),
rhs)
.setSymbol(sym).setType(definitions.UNIT_TYPE);
}
public Tree ValDef(Symbol sym, Tree rhs) {
return ValDef(sym.pos, sym, rhs);
}
/** Build and attribute value/variable/let definition node whose signature
* corresponds to given symbol and which has given body.
*/
public Tree DefDef(int pos, Symbol sym, Tree body) {
Global.instance.nextPhase();
Type symtype = sym.type();
Global.instance.prevPhase();
return make.DefDef(pos,
sym.flags & SOURCEFLAGS,
sym.name,
mkTypeParams(pos, symtype.typeParams()),
mkParams(pos, symtype),
TypeTerm(pos, symtype.resultType()),
body)
.setSymbol(sym).setType(definitions.UNIT_TYPE);
}
public Tree DefDef(Symbol sym, Tree rhs) {
return DefDef(sym.pos, sym, rhs);
}
/** Generate class definition from class symbol, parent constructors, and body.
*/
public Tree ClassDef(int pos, Symbol clazz, Tree[] constrs, Tree[] body) {
Global.instance.nextPhase();
Type clazzinfo = clazz.info();
Type constrtype = clazz.constructor().info();
Global.instance.prevPhase();
switch (clazzinfo) {
case CompoundType(Type[] parents, Scope members):
Template templ = make.Template(pos, constrs, body);
templ.setType(clazzinfo);
templ.setSymbol(localDummy(pos, clazz.owner()));
return make.ClassDef(
pos,
clazz.flags & SOURCEFLAGS,
clazz.name,
mkTypeParams(pos, constrtype.typeParams()),
mkParams(pos, constrtype),
Tree.Empty,
templ)
.setSymbol(clazz).setType(definitions.UNIT_TYPE);
default:
throw new ApplicationError();
}
}
public Tree ClassDef(Symbol clazz, Tree[] constrs, Tree[] body) {
return ClassDef(clazz.pos, clazz, constrs, body);
}
/** Generate class definition from class symbol and body.
* All parents must by parameterless, or take unit parameters.
*/
public Tree ClassDef(int pos, Symbol clazz, Tree[] body) {
Global.instance.nextPhase();
Type clazzinfo = clazz.info();
Global.instance.prevPhase();
return ClassDef(pos, clazz, mkParentConstrs(pos, clazzinfo.parents()), body);
}
public Tree ClassDef(Symbol clazz, Tree[] body) {
return ClassDef(clazz.pos, clazz, body);
}
/** Build the expansion of (() => expr)
* This is:
* { class $anon() extends scala.Function0 { def apply() = expr } ; new $anon() }
*/
public Tree mkUnitFunction(Tree expr, Type tp, Symbol owner) {
int pos = expr.pos;
Type f0t = definitions.functionType(Type.EMPTY_ARRAY, tp);
ClassSymbol clazz = new ClassSymbol(
pos, Names.ANON_CLASS_NAME.toTypeName(), owner, 0);
clazz.setInfo(Type.compoundType(new Type[]{definitions.OBJECT_TYPE, f0t},
new Scope(), clazz));
clazz.constructor().setInfo(
Type.MethodType(Symbol.EMPTY_ARRAY, clazz.typeConstructor()));
Symbol applyMeth = new TermSymbol(pos, Names.apply, clazz, FINAL)
.setInfo(Type.MethodType(Symbol.EMPTY_ARRAY, tp));
clazz.info().members().enter(applyMeth);
Tree applyDef = DefDef(applyMeth, changeOwner(expr, owner, applyMeth));
Tree classDef = ClassDef(clazz, new Tree[]{applyDef});
Tree alloc = New(pos, Type.localThisType, clazz, Tree.EMPTY_ARRAY);
return Block(new Tree[]{classDef, alloc});
}
/** Change owner of all defined symbols from `prevOwner' to `newOwner'
*/
public Tree changeOwner(Tree tree, final Symbol prevOwner, final Symbol newOwner) {
Transformer lifter = new Transformer(global) {
public Tree transform(Tree tree) {
if (TreeInfo.isDefinition(tree)) {
Symbol sym = tree.symbol();
if (sym != null && sym.owner() == prevOwner) {
sym.setOwner(newOwner);
}
}
return super.transform(tree);
}
};
return lifter.transform(tree);
}
}
|