node.c

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/**********************************************************************

  node.c - ruby node tree

  $Author: mame $
  created at: 09/12/06 21:23:44 JST

  Copyright (C) 2009 Yusuke Endoh

**********************************************************************/

#include "ruby/ruby.h"
#include "vm_core.h"

#define A(str) rb_str_cat2(buf, (str))
#define AR(str) rb_str_concat(buf, (str))

#define A_INDENT add_indent(buf, indent)
#define D_INDENT rb_str_cat2(indent, next_indent)
#define D_DEDENT rb_str_resize(indent, RSTRING_LEN(indent) - 4)
#define A_ID(id) add_id(buf, (id))
#define A_INT(val) rb_str_catf(buf, "%d", (val))
#define A_LONG(val) rb_str_catf(buf, "%ld", (val))
#define A_LIT(lit) AR(rb_inspect(lit))
#define A_NODE_HEADER(node, term) \
    rb_str_catf(buf, "@ %s (line: %d, column: %d)"term, ruby_node_name(nd_type(node)), nd_line(node), nd_column(node))
#define A_FIELD_HEADER(len, name, term) \
    rb_str_catf(buf, "+- %.*s:"term, (len), (name))
#define D_FIELD_HEADER(len, name, term) (A_INDENT, A_FIELD_HEADER(len, name, term))

#define D_NULL_NODE (A_INDENT, A("(null node)\n"))
#define D_NODE_HEADER(node) (A_INDENT, A_NODE_HEADER(node, "\n"))

#define COMPOUND_FIELD(len, name, block) \
    do { \
        D_FIELD_HEADER((len), (name), "\n");    \
        D_INDENT; \
        block; \
        D_DEDENT; \
    } while (0)

#define COMPOUND_FIELD1(name, ann, block) \
    COMPOUND_FIELD(FIELD_NAME_LEN(name, ann), \
                   FIELD_NAME_DESC(name, ann), \
                   block)

#define FIELD_NAME_DESC(name, ann) name " (" ann ")"
#define FIELD_NAME_LEN(name, ann) (int)( \
        comment ? \
        rb_strlen_lit(FIELD_NAME_DESC(name, ann)) : \
        rb_strlen_lit(name))
#define SIMPLE_FIELD(len, name) \
    for (D_FIELD_HEADER((len), (name), " "), field_flag = 1; \
         field_flag; /* should be optimized away */ \
         A("\n"), field_flag = 0)

#define SIMPLE_FIELD1(name, ann)    SIMPLE_FIELD(FIELD_NAME_LEN(name, ann), FIELD_NAME_DESC(name, ann))
#define F_CUSTOM1(name, ann)        SIMPLE_FIELD1(#name, ann)
#define F_ID(name, ann)             SIMPLE_FIELD1(#name, ann) A_ID(node->name)
#define F_GENTRY(name, ann)         SIMPLE_FIELD1(#name, ann) A_ID((node->name)->id)
#define F_INT(name, ann)            SIMPLE_FIELD1(#name, ann) A_INT(node->name)
#define F_LONG(name, ann)           SIMPLE_FIELD1(#name, ann) A_LONG(node->name)
#define F_LIT(name, ann)            SIMPLE_FIELD1(#name, ann) A_LIT(node->name)
#define F_MSG(name, ann, desc)      SIMPLE_FIELD1(#name, ann) A(desc)

#define F_NODE(name, ann) \
    COMPOUND_FIELD1(#name, ann, dump_node(buf, indent, comment, node->name))
#define F_OPTION(name, ann) \
    COMPOUND_FIELD1(#name, ann, dump_option(buf, indent, node->name))

#define ANN(ann) \
    if (comment) { \
        A_INDENT; A("| # " ann "\n"); \
    }

#define LAST_NODE (next_indent = "    ")

static void
add_indent(VALUE buf, VALUE indent)
{
    AR(indent);
}

static void
add_id(VALUE buf, ID id)
{
    if (id == 0) {
        A("(null)");
    }
    else {
        VALUE str = rb_id2str(id);
        if (str) {
            A(":"); AR(str);
        }
        else {
            A("(internal variable)");
        }
    }
}

struct add_option_arg {
    VALUE buf, indent;
    st_index_t count;
};

static int
add_option_i(VALUE key, VALUE val, VALUE args)
{
    struct add_option_arg *argp = (void *)args;
    VALUE buf = argp->buf;
    VALUE indent = argp->indent;

    A_INDENT;
    A("+- ");
    AR(rb_sym2str(key));
    A(": ");
    A_LIT(val);
    A("\n");
    return ST_CONTINUE;
}

static void
dump_option(VALUE buf, VALUE indent, VALUE opt)
{
    struct add_option_arg arg;

    if (!RB_TYPE_P(opt, T_HASH)) {
        A_LIT(opt);
        return;
    }
    arg.buf = buf;
    arg.indent = indent;
    arg.count = 0;
    rb_hash_foreach(opt, add_option_i, (VALUE)&arg);
}

static void dump_node(VALUE, VALUE, int, NODE *);
static const char default_indent[] = "|   ";

static void
dump_array(VALUE buf, VALUE indent, int comment, NODE *node)
{
    int field_flag;
    const char *next_indent = default_indent;
    F_LONG(nd_alen, "length");
    F_NODE(nd_head, "element");
    while (node->nd_next && nd_type(node->nd_next) == NODE_ARRAY) {
        node = node->nd_next;
        F_NODE(nd_head, "element");
    }
    LAST_NODE;
    F_NODE(nd_next, "next element");
}

static void
dump_node(VALUE buf, VALUE indent, int comment, NODE *node)
{
    int field_flag;
    int i;
    const char *next_indent = default_indent;
    enum node_type type;

    if (!node) {
        D_NULL_NODE;
        return;
    }

    D_NODE_HEADER(node);

    type = nd_type(node);
    switch (type) {
      case NODE_BLOCK:
        ANN("statement sequence");
        ANN("format: [nd_head]; ...; [nd_next]");
        ANN("example: foo; bar");
        i = 0;
        do {
            A_INDENT;
            rb_str_catf(buf, "+- nd_head (%s%d):\n",
                        comment ? "statement #" : "", ++i);
            if (!node->nd_next) LAST_NODE;
            D_INDENT;
            dump_node(buf, indent, comment, node->nd_head);
            D_DEDENT;
        } while (node->nd_next &&
                 nd_type(node->nd_next) == NODE_BLOCK &&
                 (node = node->nd_next, 1));
        if (node->nd_next) {
            LAST_NODE;
            F_NODE(nd_next, "next block");
        }
        return;

      case NODE_IF:
        ANN("if statement");
        ANN("format: if [nd_cond] then [nd_body] else [nd_else] end");
        ANN("example: if x == 1 then foo else bar end");
        F_NODE(nd_cond, "condition expr");
        F_NODE(nd_body, "then clause");
        LAST_NODE;
        F_NODE(nd_else, "else clause");
        return;

      case NODE_UNLESS:
        ANN("unless statement");
        ANN("format: unless [nd_cond] then [nd_body] else [nd_else] end");
        ANN("example: unless x == 1 then foo else bar end");
        F_NODE(nd_cond, "condition expr");
        F_NODE(nd_body, "then clause");
        LAST_NODE;
        F_NODE(nd_else, "else clause");
        return;

      case NODE_CASE:
        ANN("case statement");
        ANN("format: case [nd_head]; [nd_body]; end");
        ANN("example: case x; when 1; foo; when 2; bar; else baz; end");
        F_NODE(nd_head, "case expr");
        LAST_NODE;
        F_NODE(nd_body, "when clauses");
        return;

      case NODE_WHEN:
        ANN("if statement");
        ANN("format: when [nd_head]; [nd_body]; (when or else) [nd_next]");
        ANN("example: case x; when 1; foo; when 2; bar; else baz; end");
        F_NODE(nd_head, "when value");
        F_NODE(nd_body, "when clause");
        LAST_NODE;
        F_NODE(nd_next, "next when clause");
        return;

      case NODE_OPT_N:
        ANN("wrapper for -n option");
        ANN("format: ruby -ne '[nd_body]' (nd_cond is `gets')");
        ANN("example: ruby -ne 'p $_'");
        goto loop;
      case NODE_WHILE:
        ANN("while statement");
        ANN("format: while [nd_cond]; [nd_body]; end");
        ANN("example: while x == 1; foo; end");
        goto loop;
      case NODE_UNTIL:
        ANN("until statement");
        ANN("format: until [nd_cond]; [nd_body]; end");
        ANN("example: until x == 1; foo; end");
      loop:
        F_CUSTOM1(nd_state, "begin-end-while?") {
            A_INT((int)node->nd_state);
            A((node->nd_state == 1) ? " (while-end)" : " (begin-end-while)");
        }
        F_NODE(nd_cond, "condition");
        LAST_NODE;
        F_NODE(nd_body, "body");
        return;

      case NODE_ITER:
        ANN("method call with block");
        ANN("format: [nd_iter] { [nd_body] }");
        ANN("example: 3.times { foo }");
        goto iter;
      case NODE_FOR:
        ANN("for statement");
        ANN("format: for * in [nd_iter] do [nd_body] end");
        ANN("example: for i in 1..3 do foo end");
      iter:
        F_NODE(nd_iter, "iteration receiver");
        LAST_NODE;
        F_NODE(nd_body, "body");
        return;

      case NODE_BREAK:
        ANN("for statement");
        ANN("format: break [nd_stts]");
        ANN("example: break 1");
        goto jump;
      case NODE_NEXT:
        ANN("next statement");
        ANN("format: next [nd_stts]");
        ANN("example: next 1");
        goto jump;
      case NODE_RETURN:
        ANN("return statement");
        ANN("format: return [nd_stts]");
        ANN("example: return 1");
      jump:
        LAST_NODE;
        F_NODE(nd_stts, "value");
        return;

      case NODE_REDO:
        ANN("redo statement");
        ANN("format: redo");
        ANN("example: redo");
        return;

      case NODE_RETRY:
        ANN("retry statement");
        ANN("format: retry");
        ANN("example: retry");
        return;

      case NODE_BEGIN:
        ANN("begin statement");
        ANN("format: begin; [nd_body]; end");
        ANN("example: begin; 1; end");
        LAST_NODE;
        F_NODE(nd_body, "body");
        return;

      case NODE_RESCUE:
        ANN("rescue clause");
        ANN("format: begin; [nd_body]; (rescue) [nd_resq]; else [nd_else]; end");
        ANN("example: begin; foo; rescue; bar; else; baz; end");
        F_NODE(nd_head, "body");
        F_NODE(nd_resq, "rescue clause list");
        LAST_NODE;
        F_NODE(nd_else, "rescue else clause");
        return;

      case NODE_RESBODY:
        ANN("rescue clause (cont'd)");
        ANN("format: rescue [nd_args]; [nd_body]; (rescue) [nd_head]");
        ANN("example: begin; foo; rescue; bar; else; baz; end");
        F_NODE(nd_args, "rescue exceptions");
        F_NODE(nd_body, "rescue clause");
        LAST_NODE;
        F_NODE(nd_head, "next rescue clause");
        return;

      case NODE_ENSURE:
        ANN("ensure clause");
        ANN("format: begin; [nd_head]; ensure; [nd_ensr]; end");
        ANN("example: begin; foo; ensure; bar; end");
        F_NODE(nd_head, "body");
        LAST_NODE;
        F_NODE(nd_ensr, "ensure clause");
        return;

      case NODE_AND:
        ANN("&& operator");
        ANN("format: [nd_1st] && [nd_2nd]");
        ANN("example: foo && bar");
        goto andor;
      case NODE_OR:
        ANN("|| operator");
        ANN("format: [nd_1st] || [nd_2nd]");
        ANN("example: foo || bar");
      andor:
        while (1) {
            F_NODE(nd_1st, "left expr");
            if (!node->nd_2nd || nd_type(node->nd_2nd) != (int)type)
                break;
            node = node->nd_2nd;
        }
        LAST_NODE;
        F_NODE(nd_2nd, "right expr");
        return;

      case NODE_MASGN:
        ANN("multiple assignment");
        ANN("format: [nd_head], [nd_args] = [nd_value]");
        ANN("example: a, b = foo");
        F_NODE(nd_value, "rhsn");
        F_NODE(nd_head, "lhsn");
        if ((VALUE)node->nd_args != (VALUE)-1) {
            LAST_NODE;
            F_NODE(nd_args, "splatn");
        }
        else {
            F_MSG(nd_args, "splatn", "-1 (rest argument without name)");
        }
        return;

      case NODE_LASGN:
        ANN("local variable assignment");
        ANN("format: [nd_vid](lvar) = [nd_value]");
        ANN("example: x = foo");
        goto asgn;
      case NODE_DASGN:
        ANN("dynamic variable assignment (out of current scope)");
        ANN("format: [nd_vid](dvar) = [nd_value]");
        ANN("example: x = nil; 1.times { x = foo }");
        goto asgn;
      case NODE_DASGN_CURR:
        ANN("dynamic variable assignment (in current scope)");
        ANN("format: [nd_vid](current dvar) = [nd_value]");
        ANN("example: 1.times { x = foo }");
        goto asgn;
      case NODE_IASGN:
        ANN("instance variable assignment");
        ANN("format: [nd_vid](ivar) = [nd_value]");
        ANN("example: @x = foo");
        goto asgn;
      case NODE_CVASGN:
        ANN("class variable assignment");
        ANN("format: [nd_vid](cvar) = [nd_value]");
        ANN("example: @@x = foo");
      asgn:
        F_ID(nd_vid, "variable");
        LAST_NODE;
        if (node->nd_value == (NODE *)-1) {
            F_MSG(nd_value, "rvalue", "(required keyword argument)");
        }
        else {
            F_NODE(nd_value, "rvalue");
        }
        return;

      case NODE_GASGN:
        ANN("global variable assignment");
        ANN("format: [nd_entry](gvar) = [nd_value]");
        ANN("example: $x = foo");
        F_GENTRY(nd_entry, "global variable");
        LAST_NODE;
        F_NODE(nd_value, "rvalue");
        return;

      case NODE_CDECL:
        ANN("constant declaration");
        ANN("format: [nd_else]::[nd_vid](constant) = [nd_value]");
        ANN("example: X = foo");
        if (node->nd_vid) {
            F_ID(nd_vid, "constant");
            F_MSG(nd_else, "extension", "not used");
        }
        else {
            F_MSG(nd_vid, "constant", "0 (see extension field)");
            F_NODE(nd_else, "extension");
        }
        LAST_NODE;
        F_NODE(nd_value, "rvalue");
        return;

      case NODE_OP_ASGN1:
        ANN("array assignment with operator");
        ANN("format: [nd_value] [ [nd_args->nd_body] ] [nd_vid]= [nd_args->nd_head]");
        ANN("example: ary[1] += foo");
        F_NODE(nd_recv, "receiver");
        F_CUSTOM1(nd_mid, "operator") {
            switch (node->nd_mid) {
              case 0: A("0 (||)"); break;
              case 1: A("1 (&&)"); break;
              default: A_ID(node->nd_mid);
            }
        }
        F_NODE(nd_args->nd_head, "index");
        LAST_NODE;
        F_NODE(nd_args->nd_body, "rvalue");
        return;

      case NODE_OP_ASGN2:
        ANN("attr assignment with operator");
        ANN("format: [nd_value].[attr] [nd_next->nd_mid]= [nd_value]");
        ANN("          where [attr]: [nd_next->nd_vid]");
        ANN("example: struct.field += foo");
        F_NODE(nd_recv, "receiver");
        F_CUSTOM1(nd_next->nd_vid, "attr") {
            if (node->nd_next->nd_aid) A("? ");
            A_ID(node->nd_next->nd_vid);
        }
        F_CUSTOM1(nd_next->nd_mid, "operator") {
            switch (node->nd_next->nd_mid) {
              case 0: A("0 (||)"); break;
              case 1: A("1 (&&)"); break;
              default: A_ID(node->nd_next->nd_mid);
            }
        }
        LAST_NODE;
        F_NODE(nd_value, "rvalue");
        return;

      case NODE_OP_ASGN_AND:
        ANN("assignment with && operator");
        ANN("format: [nd_head] &&= [nd_value]");
        ANN("example: foo &&= bar");
        goto asgn_andor;
      case NODE_OP_ASGN_OR:
        ANN("assignment with || operator");
        ANN("format: [nd_head] ||= [nd_value]");
        ANN("example: foo ||= bar");
      asgn_andor:
        F_NODE(nd_head, "variable");
        LAST_NODE;
        F_NODE(nd_value, "rvalue");
        return;

      case NODE_OP_CDECL:
        ANN("constant declaration with operator");
        ANN("format: [nd_head](constant) [nd_aid]= [nd_value]");
        ANN("example: A::B ||= 1");
        F_NODE(nd_head, "constant");
        F_CUSTOM1(nd_aid, "operator") {
            switch (node->nd_aid) {
              case 0: A("0 (||)"); break;
              case 1: A("1 (&&)"); break;
              default: A_ID(node->nd_mid);
            }
        }
        LAST_NODE;
        F_NODE(nd_value, "rvalue");
        return;

      case NODE_CALL:
      case NODE_OPCALL:
        ANN("method invocation");
        ANN("format: [nd_recv].[nd_mid]([nd_args])");
        ANN("example: obj.foo(1)");
        F_ID(nd_mid, "method id");
        F_NODE(nd_recv, "receiver");
        LAST_NODE;
        F_NODE(nd_args, "arguments");
        return;

      case NODE_FCALL:
        ANN("function call");
        ANN("format: [nd_mid]([nd_args])");
        ANN("example: foo(1)");
        F_ID(nd_mid, "method id");
        LAST_NODE;
        F_NODE(nd_args, "arguments");
        return;

      case NODE_VCALL:
        ANN("function call with no argument");
        ANN("format: [nd_mid]");
        ANN("example: foo");
        F_ID(nd_mid, "method id");
        return;

      case NODE_QCALL:
        ANN("safe method invocation");
        ANN("format: [nd_recv]&.[nd_mid]([nd_args])");
        ANN("example: obj&.foo(1)");
        F_ID(nd_mid, "method id");
        F_NODE(nd_recv, "receiver");
        LAST_NODE;
        F_NODE(nd_args, "arguments");
        return;

      case NODE_SUPER:
        ANN("super invocation");
        ANN("format: super [nd_args]");
        ANN("example: super 1");
        LAST_NODE;
        F_NODE(nd_args, "arguments");
        return;

      case NODE_ZSUPER:
        ANN("super invocation with no argument");
        ANN("format: super");
        ANN("example: super");
        return;

      case NODE_ARRAY:
        ANN("array constructor");
        ANN("format: [ [nd_head], [nd_next].. ] (length: [nd_alen])");
        ANN("example: [1, 2, 3]");
        goto ary;
      case NODE_VALUES:
        ANN("return arguments");
        ANN("format: [ [nd_head], [nd_next].. ] (length: [nd_alen])");
        ANN("example: return 1, 2, 3");
      ary:
        dump_array(buf, indent, comment, node);
        return;

      case NODE_ZARRAY:
        ANN("empty array constructor");
        ANN("format: []");
        ANN("example: []");
        return;

      case NODE_HASH:
        if (!node->nd_alen) {
            ANN("keyword arguments");
            ANN("format: nd_head");
            ANN("example: a: 1, b: 2");
        }
        else {
            ANN("hash constructor");
            ANN("format: { [nd_head] }");
            ANN("example: { 1 => 2, 3 => 4 }");
        }
        LAST_NODE;
        F_NODE(nd_head, "contents");
        return;

      case NODE_YIELD:
        ANN("yield invocation");
        ANN("format: yield [nd_head]");
        ANN("example: yield 1");
        LAST_NODE;
        F_NODE(nd_head, "arguments");
        return;

      case NODE_LVAR:
        ANN("local variable reference");
        ANN("format: [nd_vid](lvar)");
        ANN("example: x");
        F_ID(nd_vid, "local variable");
        return;
      case NODE_DVAR:
        ANN("dynamic variable reference");
        ANN("format: [nd_vid](dvar)");
        ANN("example: 1.times { x = 1; x }");
        F_ID(nd_vid, "local variable");
        return;
      case NODE_IVAR:
        ANN("instance variable reference");
        ANN("format: [nd_vid](ivar)");
        ANN("example: @x");
        F_ID(nd_vid, "instance variable");
        return;
      case NODE_CONST:
        ANN("constant reference");
        ANN("format: [nd_vid](constant)");
        ANN("example: X");
        F_ID(nd_vid, "constant");
        return;
      case NODE_CVAR:
        ANN("class variable reference");
        ANN("format: [nd_vid](cvar)");
        ANN("example: @@x");
        F_ID(nd_vid, "class variable");
        return;

      case NODE_GVAR:
        ANN("global variable reference");
        ANN("format: [nd_entry](gvar)");
        ANN("example: $x");
        F_GENTRY(nd_entry, "global variable");
        return;

      case NODE_NTH_REF:
        ANN("nth special variable reference");
        ANN("format: $[nd_nth]");
        ANN("example: $1, $2, ..");
        F_CUSTOM1(nd_nth, "variable") { A("$"); A_LONG(node->nd_nth); }
        return;

      case NODE_BACK_REF:
        ANN("back special variable reference");
        ANN("format: $[nd_nth]");
        ANN("example: $&, $`, $', $+");
        F_CUSTOM1(nd_nth, "variable") {
            char name[3];
            name[0] = '$';
            name[1] = (char)node->nd_nth;
            name[2] = '\0';
            A(name);
        }
        return;

      case NODE_MATCH:
        ANN("match expression (against $_ implicitly)");
        ANN("format: [nd_lit] (in condition)");
        ANN("example: if /foo/; foo; end");
        F_LIT(nd_lit, "regexp");
        return;

      case NODE_MATCH2:
        ANN("match expression (regexp first)");
        ANN("format: [nd_recv] =~ [nd_value]");
        ANN("example: /foo/ =~ 'foo'");
        F_NODE(nd_recv, "regexp (receiver)");
        if (!node->nd_args) LAST_NODE;
        F_NODE(nd_value, "string (argument)");
        if (node->nd_args) {
            LAST_NODE;
            F_NODE(nd_args, "named captures");
        }
        return;

      case NODE_MATCH3:
        ANN("match expression (regexp second)");
        ANN("format: [nd_recv] =~ [nd_value]");
        ANN("example: 'foo' =~ /foo/");
        F_NODE(nd_recv, "string (receiver)");
        LAST_NODE;
        F_NODE(nd_value, "regexp (argument)");
        return;

      case NODE_LIT:
        ANN("literal");
        ANN("format: [nd_lit]");
        ANN("example: 1, /foo/");
        goto lit;
      case NODE_STR:
        ANN("string literal");
        ANN("format: [nd_lit]");
        ANN("example: 'foo'");
        goto lit;
      case NODE_XSTR:
        ANN("xstring literal");
        ANN("format: [nd_lit]");
        ANN("example: `foo`");
      lit:
        F_LIT(nd_lit, "literal");
        return;

      case NODE_DSTR:
        ANN("string literal with interpolation");
        ANN("format: [nd_lit]");
        ANN("example: \"foo#{ bar }baz\"");
        goto dlit;
      case NODE_DXSTR:
        ANN("xstring literal with interpolation");
        ANN("format: [nd_lit]");
        ANN("example: `foo#{ bar }baz`");
        goto dlit;
      case NODE_DREGX:
        ANN("regexp literal with interpolation");
        ANN("format: [nd_lit]");
        ANN("example: /foo#{ bar }baz/");
        goto dlit;
      case NODE_DREGX_ONCE:
        ANN("regexp literal with interpolation and once flag");
        ANN("format: [nd_lit]");
        ANN("example: /foo#{ bar }baz/o");
        goto dlit;
      case NODE_DSYM:
        ANN("symbol literal with interpolation");
        ANN("format: [nd_lit]");
        ANN("example: :\"foo#{ bar }baz\"");
      dlit:
        F_LIT(nd_lit, "preceding string");
        F_NODE(nd_next->nd_head, "interpolation");
        LAST_NODE;
        F_NODE(nd_next->nd_next, "tailing strings");
        return;

      case NODE_EVSTR:
        ANN("interpolation expression");
        ANN("format: \"..#{ [nd_lit] }..\"");
        ANN("example: \"foo#{ bar }baz\"");
        LAST_NODE;
        F_NODE(nd_body, "body");
        return;

      case NODE_ARGSCAT:
        ANN("splat argument following arguments");
        ANN("format: ..(*[nd_head], [nd_body..])");
        ANN("example: foo(*ary, post_arg1, post_arg2)");
        F_NODE(nd_head, "preceding array");
        LAST_NODE;
        F_NODE(nd_body, "following array");
        return;

      case NODE_ARGSPUSH:
        ANN("splat argument following one argument");
        ANN("format: ..(*[nd_head], [nd_body])");
        ANN("example: foo(*ary, post_arg)");
        F_NODE(nd_head, "preceding array");
        LAST_NODE;
        F_NODE(nd_body, "following element");
        return;

      case NODE_SPLAT:
        ANN("splat argument");
        ANN("format: *[nd_head]");
        ANN("example: foo(*ary)");
        LAST_NODE;
        F_NODE(nd_head, "splat'ed array");
        return;

      case NODE_BLOCK_PASS:
        ANN("arguments with block argument");
        ANN("format: ..([nd_head], &[nd_body])");
        ANN("example: foo(x, &blk)");
        F_NODE(nd_head, "other arguments");
        LAST_NODE;
        F_NODE(nd_body, "block argument");
        return;

      case NODE_DEFN:
        ANN("method definition");
        ANN("format: def [nd_mid] [nd_defn]; end");
        ANN("example; def foo; bar; end");
        F_ID(nd_mid, "method name");
        LAST_NODE;
        F_NODE(nd_defn, "method definition");
        return;

      case NODE_DEFS:
        ANN("singleton method definition");
        ANN("format: def [nd_recv].[nd_mid] [nd_defn]; end");
        ANN("example; def obj.foo; bar; end");
        F_NODE(nd_recv, "receiver");
        F_ID(nd_mid, "method name");
        LAST_NODE;
        F_NODE(nd_defn, "method definition");
        return;

      case NODE_ALIAS:
        ANN("method alias statement");
        ANN("format: alias [u1.node] [u2.node]");
        ANN("example: alias bar foo");
        F_NODE(u1.node, "new name");
        LAST_NODE;
        F_NODE(u2.node, "old name");
        return;

      case NODE_VALIAS:
        ANN("global variable alias statement");
        ANN("format: alias [u1.id](gvar) [u2.id](gvar)");
        ANN("example: alias $y $x");
        F_ID(u1.id, "new name");
        F_ID(u2.id, "old name");
        return;

      case NODE_UNDEF:
        ANN("method alias statement");
        ANN("format: undef [u2.node]");
        ANN("example: undef foo");
        LAST_NODE;
        F_NODE(u2.node, "old name");
        return;

      case NODE_CLASS:
        ANN("class definition");
        ANN("format: class [nd_cpath] < [nd_super]; [nd_body]; end");
        ANN("example: class C2 < C; ..; end");
        F_NODE(nd_cpath, "class path");
        F_NODE(nd_super, "superclass");
        LAST_NODE;
        F_NODE(nd_body, "class definition");
        return;

      case NODE_MODULE:
        ANN("module definition");
        ANN("format: module [nd_cpath]; [nd_body]; end");
        ANN("example: module M; ..; end");
        F_NODE(nd_cpath, "module path");
        LAST_NODE;
        F_NODE(nd_body, "module definition");
        return;

      case NODE_SCLASS:
        ANN("singleton class definition");
        ANN("format: class << [nd_recv]; [nd_body]; end");
        ANN("example: class << obj; ..; end");
        F_NODE(nd_recv, "receiver");
        LAST_NODE;
        F_NODE(nd_body, "singleton class definition");
        return;

      case NODE_COLON2:
        ANN("scoped constant reference");
        ANN("format: [nd_head]::[nd_mid]");
        ANN("example: M::C");
        F_ID(nd_mid, "constant name");
        LAST_NODE;
        F_NODE(nd_head, "receiver");
        return;

      case NODE_COLON3:
        ANN("top-level constant reference");
        ANN("format: ::[nd_mid]");
        ANN("example: ::Object");
        F_ID(nd_mid, "constant name");
        return;

      case NODE_DOT2:
        ANN("range constructor (incl.)");
        ANN("format: [nd_beg]..[nd_end]");
        ANN("example: 1..5");
        goto dot;
      case NODE_DOT3:
        ANN("range constructor (excl.)");
        ANN("format: [nd_beg]...[nd_end]");
        ANN("example: 1...5");
        goto dot;
      case NODE_FLIP2:
        ANN("flip-flop condition (incl.)");
        ANN("format: [nd_beg]..[nd_end]");
        ANN("example: if (x==1)..(x==5); foo; end");
        goto dot;
      case NODE_FLIP3:
        ANN("flip-flop condition (excl.)");
        ANN("format: [nd_beg]...[nd_end]");
        ANN("example: if (x==1)...(x==5); foo; end");
      dot:
        F_NODE(nd_beg, "begin");
        LAST_NODE;
        F_NODE(nd_end, "end");
        return;

      case NODE_SELF:
        ANN("self");
        ANN("format: self");
        ANN("example: self");
        return;

      case NODE_NIL:
        ANN("nil");
        ANN("format: nil");
        ANN("example: nil");
        return;

      case NODE_TRUE:
        ANN("true");
        ANN("format: true");
        ANN("example: true");
        return;

      case NODE_FALSE:
        ANN("false");
        ANN("format: false");
        ANN("example: false");
        return;

      case NODE_ERRINFO:
        ANN("virtual reference to $!");
        ANN("format: rescue => id");
        ANN("example: rescue => id");
        return;

      case NODE_DEFINED:
        ANN("defined? expression");
        ANN("format: defined?([nd_head])");
        ANN("example: defined?(foo)");
        F_NODE(nd_head, "expr");
        return;

      case NODE_POSTEXE:
        ANN("post-execution");
        ANN("format: END { [nd_body] }");
        ANN("example: END { foo }");
        LAST_NODE;
        F_NODE(nd_body, "END clause");
        return;

      case NODE_ATTRASGN:
        ANN("attr assignment");
        ANN("format: [nd_recv].[nd_mid] = [nd_args]");
        ANN("example: struct.field = foo");
        if (node->nd_recv == (NODE *) 1) {
            F_MSG(nd_recv, "receiver", "1 (self)");
        }
        else {
            F_NODE(nd_recv, "receiver");
        }
        F_ID(nd_mid, "method name");
        LAST_NODE;
        F_NODE(nd_args, "arguments");
        return;

      case NODE_PRELUDE:
        ANN("pre-execution");
        ANN("format: BEGIN { [nd_head] }; [nd_body]");
        ANN("example: bar; BEGIN { foo }");
#define nd_compile_option u3.value
        F_NODE(nd_head, "prelude");
        if (!node->nd_compile_option) LAST_NODE;
        F_NODE(nd_body, "body");
        if (node->nd_compile_option) {
            LAST_NODE;
            F_OPTION(nd_compile_option, "compile_option");
        }
        return;

      case NODE_LAMBDA:
        ANN("lambda expression");
        ANN("format: -> [nd_body]");
        ANN("example: -> { foo }");
        LAST_NODE;
        F_NODE(nd_body, "lambda clause");
        return;

      case NODE_OPT_ARG:
        ANN("optional arguments");
        ANN("format: def method_name([nd_body=some], [nd_next..])");
        ANN("example: def foo(a, b=1, c); end");
        F_NODE(nd_body, "body");
        LAST_NODE;
        F_NODE(nd_next, "next");
        return;

      case NODE_KW_ARG:
        ANN("keyword arguments");
        ANN("format: def method_name([nd_body=some], [nd_next..])");
        ANN("example: def foo(a:1, b:2); end");
        F_NODE(nd_body, "body");
        LAST_NODE;
        F_NODE(nd_next, "next");
        return;

      case NODE_POSTARG:
        ANN("post arguments");
        ANN("format: *[nd_1st], [nd_2nd..] = ..");
        ANN("example: a, *rest, z = foo");
        if ((VALUE)node->nd_1st != (VALUE)-1) {
            F_NODE(nd_1st, "rest argument");
        }
        else {
            F_MSG(nd_1st, "rest argument", "-1 (rest argument without name)");
        }
        LAST_NODE;
        F_NODE(nd_2nd, "post arguments");
        return;

      case NODE_ARGS:
        ANN("method parameters");
        ANN("format: def method_name(.., [nd_opt=some], *[nd_rest], [nd_pid], .., &[nd_body])");
        ANN("example: def foo(a, b, opt1=1, opt2=2, *rest, y, z, &blk); end");
        F_INT(nd_ainfo->pre_args_num, "count of mandatory (pre-)arguments");
        F_NODE(nd_ainfo->pre_init, "initialization of (pre-)arguments");
        F_INT(nd_ainfo->post_args_num, "count of mandatory post-arguments");
        F_NODE(nd_ainfo->post_init, "initialization of post-arguments");
        F_ID(nd_ainfo->first_post_arg, "first post argument");
        F_ID(nd_ainfo->rest_arg, "rest argument");
        F_ID(nd_ainfo->block_arg, "block argument");
        F_NODE(nd_ainfo->opt_args, "optional arguments");
        F_NODE(nd_ainfo->kw_args, "keyword arguments");
        LAST_NODE;
        F_NODE(nd_ainfo->kw_rest_arg, "keyword rest argument");
        return;

      case NODE_SCOPE:
        ANN("new scope");
        ANN("format: [nd_tbl]: local table, [nd_args]: arguments, [nd_body]: body");
        F_CUSTOM1(nd_tbl, "local table") {
            ID *tbl = node->nd_tbl;
            int i;
            int size = tbl ? (int)*tbl++ : 0;
            if (size == 0) A("(empty)");
            for (i = 0; i < size; i++) {
                A_ID(tbl[i]); if (i < size - 1) A(",");
            }
        }
        F_NODE(nd_args, "arguments");
        LAST_NODE;
        F_NODE(nd_body, "body");
        return;

      case NODE_ARGS_AUX:
      case NODE_TO_ARY:
      case NODE_BLOCK_ARG:
      case NODE_BMETHOD:
      case NODE_LAST:
        break;
    }

    rb_bug("dump_node: unknown node: %s", ruby_node_name(nd_type(node)));
}

VALUE
rb_parser_dump_tree(NODE *node, int comment)
{
    VALUE buf = rb_str_new_cstr(
        "###########################################################\n"
        "## Do NOT use this node dump for any purpose other than  ##\n"
        "## debug and research.  Compatibility is not guaranteed. ##\n"
        "###########################################################\n\n"
    );
    dump_node(buf, rb_str_new_cstr("# "), comment, node);
    return buf;
}

void
rb_gc_free_node(VALUE obj)
{
    switch (nd_type(obj)) {
      case NODE_SCOPE:
        if (RNODE(obj)->nd_tbl) {
            xfree(RNODE(obj)->nd_tbl);
        }
        break;
      case NODE_ARGS:
        if (RNODE(obj)->nd_ainfo) {
            xfree(RNODE(obj)->nd_ainfo);
        }
        break;
    }
}

size_t
rb_node_memsize(VALUE obj)
{
    size_t size = 0;
    switch (nd_type(obj)) {
      case NODE_SCOPE:
        if (RNODE(obj)->nd_tbl) {
            size += (RNODE(obj)->nd_tbl[0]+1) * sizeof(*RNODE(obj)->nd_tbl);
        }
        break;
      case NODE_ARGS:
        if (RNODE(obj)->nd_ainfo) {
            size += sizeof(*RNODE(obj)->nd_ainfo);
        }
        break;
    }
    return size;
}

VALUE
rb_gc_mark_node(NODE *obj)
{
    switch (nd_type(obj)) {
      case NODE_IF:             /* 1,2,3 */
      case NODE_FOR:
      case NODE_ITER:
      case NODE_WHEN:
      case NODE_MASGN:
      case NODE_RESCUE:
      case NODE_RESBODY:
      case NODE_CLASS:
      case NODE_MATCH2:
        rb_gc_mark(RNODE(obj)->u2.value);
        /* fall through */
      case NODE_BLOCK:  /* 1,3 */
      case NODE_ARRAY:
      case NODE_DSTR:
      case NODE_DXSTR:
      case NODE_DREGX:
      case NODE_DREGX_ONCE:
      case NODE_ENSURE:
      case NODE_CALL:
      case NODE_DEFS:
      case NODE_OP_ASGN1:
        rb_gc_mark(RNODE(obj)->u1.value);
        /* fall through */
      case NODE_SUPER:  /* 3 */
      case NODE_FCALL:
      case NODE_DEFN:
      case NODE_ARGS_AUX:
        return RNODE(obj)->u3.value;

      case NODE_WHILE:  /* 1,2 */
      case NODE_UNTIL:
      case NODE_AND:
      case NODE_OR:
      case NODE_CASE:
      case NODE_SCLASS:
      case NODE_DOT2:
      case NODE_DOT3:
      case NODE_FLIP2:
      case NODE_FLIP3:
      case NODE_MATCH3:
      case NODE_OP_ASGN_OR:
      case NODE_OP_ASGN_AND:
      case NODE_MODULE:
      case NODE_ALIAS:
      case NODE_VALIAS:
      case NODE_ARGSCAT:
      case NODE_BLOCK_PASS:
        rb_gc_mark(RNODE(obj)->u1.value);
        /* fall through */
      case NODE_GASGN:  /* 2 */
      case NODE_LASGN:
      case NODE_DASGN:
      case NODE_DASGN_CURR:
      case NODE_IASGN:
      case NODE_CVASGN:
      case NODE_COLON3:
      case NODE_OPT_N:
      case NODE_EVSTR:
      case NODE_UNDEF:
      case NODE_POSTEXE:
        return RNODE(obj)->u2.value;

      case NODE_HASH:   /* 1 */
      case NODE_LIT:
      case NODE_STR:
      case NODE_XSTR:
      case NODE_DEFINED:
      case NODE_MATCH:
      case NODE_RETURN:
      case NODE_BREAK:
      case NODE_NEXT:
      case NODE_YIELD:
      case NODE_COLON2:
      case NODE_SPLAT:
      case NODE_TO_ARY:
        return RNODE(obj)->u1.value;

      case NODE_SCOPE:  /* 2,3 */
      case NODE_CDECL:
      case NODE_OPT_ARG:
        rb_gc_mark(RNODE(obj)->u3.value);
        return RNODE(obj)->u2.value;

      case NODE_ARGS:   /* custom */
        {
            struct rb_args_info *args = obj->u3.args;
            if (args) {
                if (args->pre_init)    rb_gc_mark((VALUE)args->pre_init);
                if (args->post_init)   rb_gc_mark((VALUE)args->post_init);
                if (args->opt_args)    rb_gc_mark((VALUE)args->opt_args);
                if (args->kw_args)     rb_gc_mark((VALUE)args->kw_args);
                if (args->kw_rest_arg) rb_gc_mark((VALUE)args->kw_rest_arg);
            }
        }
        return RNODE(obj)->u2.value;

      case NODE_ZARRAY: /* - */
      case NODE_ZSUPER:
      case NODE_VCALL:
      case NODE_GVAR:
      case NODE_LVAR:
      case NODE_DVAR:
      case NODE_IVAR:
      case NODE_CVAR:
      case NODE_NTH_REF:
      case NODE_BACK_REF:
      case NODE_REDO:
      case NODE_RETRY:
      case NODE_SELF:
      case NODE_NIL:
      case NODE_TRUE:
      case NODE_FALSE:
      case NODE_ERRINFO:
      case NODE_BLOCK_ARG:
        break;

      default:          /* unlisted NODE */
        rb_gc_mark_maybe(RNODE(obj)->u1.value);
        rb_gc_mark_maybe(RNODE(obj)->u2.value);
        rb_gc_mark_maybe(RNODE(obj)->u3.value);
    }
    return 0;
}