summaryrefslogtreecommitdiff
path: root/ast.c
blob: 8139fcd390d33d88ea3fae10cb20e8681e757bc6 (plain)
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
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
/* indent-tabs-mode: nil */
#include "internal.h"
#include "internal/parse.h"
#include "internal/symbol.h"
#include "internal/warnings.h"
#include "iseq.h"
#include "node.h"
#include "ruby.h"
#include "ruby/encoding.h"
#include "ruby/util.h"
#include "vm_core.h"

#include "builtin.h"

static VALUE rb_mAST;
static VALUE rb_cNode;

struct ASTNodeData {
    rb_ast_t *ast;
    const NODE *node;
};

static void
node_gc_mark(void *ptr)
{
    struct ASTNodeData *data = (struct ASTNodeData *)ptr;
    rb_gc_mark((VALUE)data->ast);
}

static size_t
node_memsize(const void *ptr)
{
    struct ASTNodeData *data = (struct ASTNodeData *)ptr;
    return rb_ast_memsize(data->ast);
}

static const rb_data_type_t rb_node_type = {
    "AST/node",
    {node_gc_mark, RUBY_TYPED_DEFAULT_FREE, node_memsize,},
    0, 0,
    RUBY_TYPED_FREE_IMMEDIATELY,
};

static VALUE rb_ast_node_alloc(VALUE klass);

static void
setup_node(VALUE obj, rb_ast_t *ast, const NODE *node)
{
    struct ASTNodeData *data;

    TypedData_Get_Struct(obj, struct ASTNodeData, &rb_node_type, data);
    data->ast = ast;
    data->node = node;
}

static VALUE
ast_new_internal(rb_ast_t *ast, const NODE *node)
{
    VALUE obj;

    obj = rb_ast_node_alloc(rb_cNode);
    setup_node(obj, ast, node);

    return obj;
}

static VALUE rb_ast_parse_str(VALUE str, VALUE keep_script_lines);
static VALUE rb_ast_parse_file(VALUE path, VALUE keep_script_lines);

static VALUE
ast_parse_new(void)
{
    return rb_parser_set_context(rb_parser_new(), NULL, 0);
}

static VALUE
ast_parse_done(rb_ast_t *ast)
{
    if (!ast->body.root) {
        rb_ast_dispose(ast);
        rb_exc_raise(GET_EC()->errinfo);
    }

    return ast_new_internal(ast, (NODE *)ast->body.root);
}

static VALUE
ast_s_parse(rb_execution_context_t *ec, VALUE module, VALUE str, VALUE keep_script_lines)
{
    return rb_ast_parse_str(str, keep_script_lines);
}

static VALUE
rb_ast_parse_str(VALUE str, VALUE keep_script_lines)
{
    rb_ast_t *ast = 0;

    StringValue(str);
    VALUE vparser = ast_parse_new();
    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
    ast = rb_parser_compile_string_path(vparser, Qnil, str, 1);
    return ast_parse_done(ast);
}

static VALUE
ast_s_parse_file(rb_execution_context_t *ec, VALUE module, VALUE path, VALUE keep_script_lines)
{
    return rb_ast_parse_file(path, keep_script_lines);
}

static VALUE
rb_ast_parse_file(VALUE path, VALUE keep_script_lines)
{
    VALUE f;
    rb_ast_t *ast = 0;
    rb_encoding *enc = rb_utf8_encoding();

    FilePathValue(path);
    f = rb_file_open_str(path, "r");
    rb_funcall(f, rb_intern("set_encoding"), 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
    VALUE vparser = ast_parse_new();
    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
    ast = rb_parser_compile_file_path(vparser, Qnil, f, 1);
    rb_io_close(f);
    return ast_parse_done(ast);
}

static VALUE
lex_array(VALUE array, int index)
{
    VALUE str = rb_ary_entry(array, index);
    if (!NIL_P(str)) {
        StringValue(str);
        if (!rb_enc_asciicompat(rb_enc_get(str))) {
            rb_raise(rb_eArgError, "invalid source encoding");
        }
    }
    return str;
}

static VALUE
rb_ast_parse_array(VALUE array, VALUE keep_script_lines)
{
    rb_ast_t *ast = 0;

    array = rb_check_array_type(array);
    VALUE vparser = ast_parse_new();
    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
    ast = rb_parser_compile_generic(vparser, lex_array, Qnil, array, 1);
    return ast_parse_done(ast);
}

static VALUE node_children(rb_ast_t*, const NODE*);

static VALUE
node_find(VALUE self, const int node_id)
{
    VALUE ary;
    long i;
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    if (nd_node_id(data->node) == node_id) return self;

    ary = node_children(data->ast, data->node);

    for (i = 0; i < RARRAY_LEN(ary); i++) {
        VALUE child = RARRAY_AREF(ary, i);

        if (CLASS_OF(child) == rb_cNode) {
            VALUE result = node_find(child, node_id);
            if (RTEST(result)) return result;
        }
    }

    return Qnil;
}

extern VALUE rb_e_script;

static VALUE
script_lines(VALUE path)
{
    VALUE hash, lines;
    ID script_lines;
    CONST_ID(script_lines, "SCRIPT_LINES__");
    if (!rb_const_defined_at(rb_cObject, script_lines)) return Qnil;
    hash = rb_const_get_at(rb_cObject, script_lines);
    if (!RB_TYPE_P(hash, T_HASH)) return Qnil;
    lines = rb_hash_lookup(hash, path);
    if (!RB_TYPE_P(lines, T_ARRAY)) return Qnil;
    return lines;
}

static VALUE
ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script_lines)
{
    VALUE path, node, lines = Qnil;
    int node_id;

    if (rb_frame_info_p(body)) {
        rb_frame_info_get(body, &path, &lines, &node_id);
        if (NIL_P(path) && NIL_P(lines)) return Qnil;
    }
    else {
        const rb_iseq_t *iseq = NULL;

        if (rb_obj_is_proc(body)) {
            iseq = vm_proc_iseq(body);

            if (!rb_obj_is_iseq((VALUE)iseq)) return Qnil;
        }
        else {
            iseq = rb_method_iseq(body);
        }
        if (!iseq) {
            return Qnil;
        }
        if (rb_iseq_from_eval_p(iseq)) {
            rb_raise(rb_eArgError, "cannot get AST for method defined in eval");
        }
        path = rb_iseq_path(iseq);
        lines = iseq->body->variable.script_lines;
        node_id = iseq->body->location.node_id;
    }

    if (!NIL_P(lines) || !NIL_P(lines = script_lines(path))) {
        node = rb_ast_parse_array(lines, keep_script_lines);
    }
    else if (RSTRING_LEN(path) == 2 && memcmp(RSTRING_PTR(path), "-e", 2) == 0) {
        node = rb_ast_parse_str(rb_e_script, keep_script_lines);
    }
    else {
        node = rb_ast_parse_file(path, keep_script_lines);
    }

    return node_find(node, node_id);
}

static VALUE
rb_ast_node_alloc(VALUE klass)
{
    struct ASTNodeData *data;
    VALUE obj = TypedData_Make_Struct(klass, struct ASTNodeData, &rb_node_type, data);

    return obj;
}

static const char*
node_type_to_str(const NODE *node)
{
    return (ruby_node_name(nd_type(node)) + rb_strlen_lit("NODE_"));
}

static VALUE
ast_node_type(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return rb_sym_intern_ascii_cstr(node_type_to_str(data->node));
}

static VALUE
ast_node_node_id(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return INT2FIX(nd_node_id(data->node));
}

#define NEW_CHILD(ast, node) node ? ast_new_internal(ast, node) : Qnil

static VALUE
rb_ary_new_from_node_args(rb_ast_t *ast, long n, ...)
{
    va_list ar;
    VALUE ary;
    long i;

    ary = rb_ary_new2(n);

    va_start(ar, n);
    for (i=0; i<n; i++) {
        NODE *node;
        node = va_arg(ar, NODE *);
        rb_ary_push(ary, NEW_CHILD(ast, node));
    }
    va_end(ar);
    return ary;
}

static VALUE
dump_block(rb_ast_t *ast, const NODE *node)
{
    VALUE ary = rb_ary_new();
    do {
        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
    } while (node->nd_next &&
        nd_type(node->nd_next) == NODE_BLOCK &&
        (node = node->nd_next, 1));
    if (node->nd_next) {
        rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));
    }

    return ary;
}

static VALUE
dump_array(rb_ast_t *ast, const NODE *node)
{
    VALUE ary = rb_ary_new();
    rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));

    while (node->nd_next && nd_type(node->nd_next) == NODE_LIST) {
        node = node->nd_next;
        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
    }
    rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));

    return ary;
}

static VALUE
var_name(ID id)
{
    if (!id) return Qnil;
    if (!rb_id2str(id)) return Qnil;
    return ID2SYM(id);
}

static VALUE
no_name_rest(void)
{
    ID rest;
    CONST_ID(rest, "NODE_SPECIAL_NO_NAME_REST");
    return ID2SYM(rest);
}

static VALUE
rest_arg(rb_ast_t *ast, const NODE *rest_arg)
{
    return NODE_NAMED_REST_P(rest_arg) ? NEW_CHILD(ast, rest_arg) : no_name_rest();
}

static VALUE
node_children(rb_ast_t *ast, const NODE *node)
{
    char name[DECIMAL_SIZE_OF_BITS(sizeof(long) * CHAR_BIT) + 2]; /* including '$' */

    enum node_type type = nd_type(node);
    switch (type) {
      case NODE_BLOCK:
        return dump_block(ast, node);
      case NODE_IF:
        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
      case NODE_UNLESS:
        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
      case NODE_CASE:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_CASE2:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_CASE3:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_WHEN:
        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
      case NODE_IN:
        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
      case NODE_WHILE:
      case NODE_UNTIL:
        return rb_ary_push(rb_ary_new_from_node_args(ast, 2, node->nd_cond, node->nd_body),
                           RBOOL(node->nd_state));
      case NODE_ITER:
      case NODE_FOR:
        return rb_ary_new_from_node_args(ast, 2, node->nd_iter, node->nd_body);
      case NODE_FOR_MASGN:
        return rb_ary_new_from_node_args(ast, 1, node->nd_var);
      case NODE_BREAK:
      case NODE_NEXT:
      case NODE_RETURN:
        return rb_ary_new_from_node_args(ast, 1, node->nd_stts);
      case NODE_REDO:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_RETRY:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_BEGIN:
        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
      case NODE_RESCUE:
        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_resq, node->nd_else);
      case NODE_RESBODY:
        return rb_ary_new_from_node_args(ast, 3, node->nd_args, node->nd_body, node->nd_head);
      case NODE_ENSURE:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_ensr);
      case NODE_AND:
      case NODE_OR:
        {
            VALUE ary = rb_ary_new();

            while (1) {
                rb_ary_push(ary, NEW_CHILD(ast, node->nd_1st));
                if (!node->nd_2nd || nd_type(node->nd_2nd) != (int)type)
                    break;
                node = node->nd_2nd;
            }
            rb_ary_push(ary, NEW_CHILD(ast, node->nd_2nd));
            return ary;
        }
      case NODE_MASGN:
        if (NODE_NAMED_REST_P(node->nd_args)) {
            return rb_ary_new_from_node_args(ast, 3, node->nd_value, node->nd_head, node->nd_args);
        }
        else {
            return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_value),
                                        NEW_CHILD(ast, node->nd_head),
                                        no_name_rest());
        }
      case NODE_LASGN:
      case NODE_DASGN:
      case NODE_DASGN_CURR:
      case NODE_IASGN:
      case NODE_CVASGN:
      case NODE_GASGN:
        if (NODE_REQUIRED_KEYWORD_P(node)) {
            return rb_ary_new_from_args(2, var_name(node->nd_vid), ID2SYM(rb_intern("NODE_SPECIAL_REQUIRED_KEYWORD")));
        }
        return rb_ary_new_from_args(2, var_name(node->nd_vid), NEW_CHILD(ast, node->nd_value));
      case NODE_CDECL:
        if (node->nd_vid) {
            return rb_ary_new_from_args(2, ID2SYM(node->nd_vid), NEW_CHILD(ast, node->nd_value));
        }
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_else), ID2SYM(node->nd_else->nd_mid), NEW_CHILD(ast, node->nd_value));
      case NODE_OP_ASGN1:
        return rb_ary_new_from_args(4, NEW_CHILD(ast, node->nd_recv),
                                    ID2SYM(node->nd_mid),
                                    NEW_CHILD(ast, node->nd_args->nd_head),
                                    NEW_CHILD(ast, node->nd_args->nd_body));
      case NODE_OP_ASGN2:
        return rb_ary_new_from_args(5, NEW_CHILD(ast, node->nd_recv),
                                    RBOOL(node->nd_next->nd_aid),
                                    ID2SYM(node->nd_next->nd_vid),
                                    ID2SYM(node->nd_next->nd_mid),
                                    NEW_CHILD(ast, node->nd_value));
      case NODE_OP_ASGN_AND:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idANDOP),
                                    NEW_CHILD(ast, node->nd_value));
      case NODE_OP_ASGN_OR:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idOROP),
                                    NEW_CHILD(ast, node->nd_value));
      case NODE_OP_CDECL:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head),
                                    ID2SYM(node->nd_aid),
                                    NEW_CHILD(ast, node->nd_value));
      case NODE_CALL:
      case NODE_OPCALL:
      case NODE_QCALL:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv),
                                    ID2SYM(node->nd_mid),
                                    NEW_CHILD(ast, node->nd_args));
      case NODE_FCALL:
        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid),
                                    NEW_CHILD(ast, node->nd_args));
      case NODE_VCALL:
        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
      case NODE_SUPER:
        return rb_ary_new_from_node_args(ast, 1, node->nd_args);
      case NODE_ZSUPER:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_LIST:
      case NODE_VALUES:
        return dump_array(ast, node);
      case NODE_ZLIST:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_HASH:
        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
      case NODE_YIELD:
        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
      case NODE_LVAR:
      case NODE_DVAR:
        return rb_ary_new_from_args(1, var_name(node->nd_vid));
      case NODE_IVAR:
      case NODE_CONST:
      case NODE_CVAR:
      case NODE_GVAR:
        return rb_ary_new_from_args(1, ID2SYM(node->nd_vid));
      case NODE_NTH_REF:
        snprintf(name, sizeof(name), "$%ld", node->nd_nth);
        return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
      case NODE_BACK_REF:
        name[0] = '$';
        name[1] = (char)node->nd_nth;
        name[2] = '\0';
        return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
      case NODE_MATCH2:
        if (node->nd_args) {
            return rb_ary_new_from_node_args(ast, 3, node->nd_recv, node->nd_value, node->nd_args);
        }
        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
      case NODE_MATCH3:
        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
      case NODE_MATCH:
      case NODE_LIT:
      case NODE_STR:
      case NODE_XSTR:
        return rb_ary_new_from_args(1, node->nd_lit);
      case NODE_ONCE:
        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
      case NODE_DSTR:
      case NODE_DXSTR:
      case NODE_DREGX:
      case NODE_DSYM:
        {
            NODE *n = node->nd_next;
            VALUE head = Qnil, next = Qnil;
            if (n) {
                head = NEW_CHILD(ast, n->nd_head);
                next = NEW_CHILD(ast, n->nd_next);
            }
            return rb_ary_new_from_args(3, node->nd_lit, head, next);
        }
      case NODE_EVSTR:
        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
      case NODE_ARGSCAT:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_ARGSPUSH:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_SPLAT:
        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
      case NODE_BLOCK_PASS:
        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
      case NODE_DEFN:
        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
      case NODE_DEFS:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
      case NODE_ALIAS:
        return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
      case NODE_VALIAS:
        return rb_ary_new_from_args(2, ID2SYM(node->nd_alias), ID2SYM(node->nd_orig));
      case NODE_UNDEF:
        return rb_ary_new_from_node_args(ast, 1, node->nd_undef);
      case NODE_CLASS:
        return rb_ary_new_from_node_args(ast, 3, node->nd_cpath, node->nd_super, node->nd_body);
      case NODE_MODULE:
        return rb_ary_new_from_node_args(ast, 2, node->nd_cpath, node->nd_body);
      case NODE_SCLASS:
        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_body);
      case NODE_COLON2:
        return rb_ary_new_from_args(2, NEW_CHILD(ast, node->nd_head), ID2SYM(node->nd_mid));
      case NODE_COLON3:
        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
      case NODE_DOT2:
      case NODE_DOT3:
      case NODE_FLIP2:
      case NODE_FLIP3:
        return rb_ary_new_from_node_args(ast, 2, node->nd_beg, node->nd_end);
      case NODE_SELF:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_NIL:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_TRUE:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_FALSE:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_ERRINFO:
        return rb_ary_new_from_node_args(ast, 0);
      case NODE_DEFINED:
        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
      case NODE_POSTEXE:
        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
      case NODE_ATTRASGN:
        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_args));
      case NODE_LAMBDA:
        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
      case NODE_OPT_ARG:
        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
      case NODE_KW_ARG:
        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
      case NODE_POSTARG:
        if (NODE_NAMED_REST_P(node->nd_1st)) {
            return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
        }
        return rb_ary_new_from_args(2, no_name_rest(),
                                    NEW_CHILD(ast, node->nd_2nd));
      case NODE_ARGS:
        {
            struct rb_args_info *ainfo = node->nd_ainfo;
            return rb_ary_new_from_args(10,
                                        INT2NUM(ainfo->pre_args_num),
                                        NEW_CHILD(ast, ainfo->pre_init),
                                        NEW_CHILD(ast, ainfo->opt_args),
                                        var_name(ainfo->first_post_arg),
                                        INT2NUM(ainfo->post_args_num),
                                        NEW_CHILD(ast, ainfo->post_init),
                                        (ainfo->rest_arg == NODE_SPECIAL_EXCESSIVE_COMMA
                                            ? ID2SYM(rb_intern("NODE_SPECIAL_EXCESSIVE_COMMA"))
                                            : var_name(ainfo->rest_arg)),
                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_args)),
                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_rest_arg)),
                                        var_name(ainfo->block_arg));
        }
      case NODE_SCOPE:
        {
            rb_ast_id_table_t *tbl = node->nd_tbl;
            int i, size = tbl ? tbl->size : 0;
            VALUE locals = rb_ary_new_capa(size);
            for (i = 0; i < size; i++) {
                rb_ary_push(locals, var_name(tbl->ids[i]));
            }
            return rb_ary_new_from_args(3, locals, NEW_CHILD(ast, node->nd_args), NEW_CHILD(ast, node->nd_body));
        }
      case NODE_ARYPTN:
        {
            struct rb_ary_pattern_info *apinfo = node->nd_apinfo;
            VALUE rest = rest_arg(ast, apinfo->rest_arg);
            return rb_ary_new_from_args(4,
                                        NEW_CHILD(ast, node->nd_pconst),
                                        NEW_CHILD(ast, apinfo->pre_args),
                                        rest,
                                        NEW_CHILD(ast, apinfo->post_args));
        }
      case NODE_FNDPTN:
        {
            struct rb_fnd_pattern_info *fpinfo = node->nd_fpinfo;
            VALUE pre_rest = rest_arg(ast, fpinfo->pre_rest_arg);
            VALUE post_rest = rest_arg(ast, fpinfo->post_rest_arg);
            return rb_ary_new_from_args(4,
                                        NEW_CHILD(ast, node->nd_pconst),
                                        pre_rest,
                                        NEW_CHILD(ast, fpinfo->args),
                                        post_rest);
        }
      case NODE_HSHPTN:
        {
            VALUE kwrest = node->nd_pkwrestarg == NODE_SPECIAL_NO_REST_KEYWORD ? ID2SYM(rb_intern("NODE_SPECIAL_NO_REST_KEYWORD")) :
                                                                                 NEW_CHILD(ast, node->nd_pkwrestarg);

            return rb_ary_new_from_args(3,
                                        NEW_CHILD(ast, node->nd_pconst),
                                        NEW_CHILD(ast, node->nd_pkwargs),
                                        kwrest);
        }
      case NODE_ARGS_AUX:
      case NODE_LAST:
        break;
    }

    rb_bug("node_children: unknown node: %s", ruby_node_name(type));
}

static VALUE
ast_node_children(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return node_children(data->ast, data->node);
}

static VALUE
ast_node_first_lineno(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return INT2NUM(nd_first_lineno(data->node));
}

static VALUE
ast_node_first_column(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return INT2NUM(nd_first_column(data->node));
}

static VALUE
ast_node_last_lineno(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return INT2NUM(nd_last_lineno(data->node));
}

static VALUE
ast_node_last_column(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    return INT2NUM(nd_last_column(data->node));
}

static VALUE
ast_node_inspect(rb_execution_context_t *ec, VALUE self)
{
    VALUE str;
    VALUE cname;
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);

    cname = rb_class_path(rb_obj_class(self));
    str = rb_str_new2("#<");

    rb_str_append(str, cname);
    rb_str_catf(str, ":%s@%d:%d-%d:%d>",
                node_type_to_str(data->node),
                nd_first_lineno(data->node), nd_first_column(data->node),
                nd_last_lineno(data->node), nd_last_column(data->node));

    return str;
}

static VALUE
ast_node_script_lines(rb_execution_context_t *ec, VALUE self)
{
    struct ASTNodeData *data;
    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
    VALUE ret = data->ast->body.script_lines;
    if (!RB_TYPE_P(ret, T_ARRAY)) return Qnil;
    return ret;
}

#include "ast.rbinc"

void
Init_ast(void)
{
    rb_mAST = rb_define_module_under(rb_cRubyVM, "AbstractSyntaxTree");
    rb_cNode = rb_define_class_under(rb_mAST, "Node", rb_cObject);
    rb_undef_alloc_func(rb_cNode);
}