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<h1 style="margin:8px;" id="f1">parse.y&nbsp;&nbsp;&nbsp;<span style="font-weight: normal; font-size: 0.5em;">[<a href="?txt">plain text</a>]</span></h1>
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/**********************************************************************

  parse.y -

  $Author: shyouhei $
  $Date: 2008-06-29 16:52:47 +0900 (Sun, 29 Jun 2008) $
  created at: Fri May 28 18:02:42 JST 1993

  Copyright (C) 1993-2003 Yukihiro Matsumoto

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

%{

#define YYDEBUG 1
#define YYERROR_VERBOSE 1
#ifndef YYSTACK_USE_ALLOCA
#define YYSTACK_USE_ALLOCA 0
#endif

#include &quot;ruby.h&quot;
#include &quot;env.h&quot;
#include &quot;intern.h&quot;
#include &quot;node.h&quot;
#include &quot;st.h&quot;
#include &lt;stdio.h&gt;
#include &lt;errno.h&gt;
#include &lt;ctype.h&gt;

#define YYMALLOC	rb_parser_malloc
#define YYREALLOC	rb_parser_realloc
#define YYCALLOC	rb_parser_calloc
#define YYFREE 	rb_parser_free
#define malloc	YYMALLOC
#define realloc	YYREALLOC
#define calloc	YYCALLOC
#define free	YYFREE
static void *rb_parser_malloc _((size_t));
static void *rb_parser_realloc _((void *, size_t));
static void *rb_parser_calloc _((size_t, size_t));
static void rb_parser_free _((void *));

#define yyparse ruby_yyparse
#define yylex ruby_yylex
#define yyerror ruby_yyerror
#define yylval ruby_yylval
#define yychar ruby_yychar
#define yydebug ruby_yydebug

#define ID_SCOPE_SHIFT 3
#define ID_SCOPE_MASK 0x07
#define ID_LOCAL    0x01
#define ID_INSTANCE 0x02
#define ID_GLOBAL   0x03
#define ID_ATTRSET  0x04
#define ID_CONST    0x05
#define ID_CLASS    0x06
#define ID_JUNK     0x07
#define ID_INTERNAL ID_JUNK

#define is_notop_id(id) ((id)&gt;tLAST_TOKEN)
#define is_local_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_LOCAL)
#define is_global_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_GLOBAL)
#define is_instance_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_INSTANCE)
#define is_attrset_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_ATTRSET)
#define is_const_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_CONST)
#define is_class_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_CLASS)
#define is_junk_id(id) (is_notop_id(id)&amp;&amp;((id)&amp;ID_SCOPE_MASK)==ID_JUNK)

#define is_asgn_or_id(id) ((is_notop_id(id)) &amp;&amp; \
	(((id)&amp;ID_SCOPE_MASK) == ID_GLOBAL || \
	 ((id)&amp;ID_SCOPE_MASK) == ID_INSTANCE || \
	 ((id)&amp;ID_SCOPE_MASK) == ID_CLASS))

NODE *ruby_eval_tree_begin = 0;
NODE *ruby_eval_tree = 0;

char *ruby_sourcefile;		/* current source file */
int   ruby_sourceline;		/* current line no. */

static int yylex();
static int yyerror();

static enum lex_state {
    EXPR_BEG,			/* ignore newline, +/- is a sign. */
    EXPR_END,			/* newline significant, +/- is an operator. */
    EXPR_ARG,			/* newline significant, +/- is an operator. */
    EXPR_CMDARG,		/* newline significant, +/- is an operator. */
    EXPR_ENDARG,		/* newline significant, +/- is an operator. */
    EXPR_MID,			/* newline significant, +/- is an operator. */
    EXPR_FNAME,			/* ignore newline, no reserved words. */
    EXPR_DOT,			/* right after `.' or `::', no reserved words. */
    EXPR_CLASS,			/* immediate after `class', no here document. */
} lex_state;
static NODE *lex_strterm;

#ifdef HAVE_LONG_LONG
typedef unsigned LONG_LONG stack_type;
#else
typedef unsigned long stack_type;
#endif

#define BITSTACK_PUSH(stack, n)	(stack = (stack&lt;&lt;1)|((n)&amp;1))
#define BITSTACK_POP(stack)	(stack &gt;&gt;= 1)
#define BITSTACK_LEXPOP(stack)	(stack = (stack &gt;&gt; 1) | (stack &amp; 1))
#define BITSTACK_SET_P(stack)	(stack&amp;1)

static stack_type cond_stack = 0;
#define COND_PUSH(n)	BITSTACK_PUSH(cond_stack, n)
#define COND_POP()	BITSTACK_POP(cond_stack)
#define COND_LEXPOP()	BITSTACK_LEXPOP(cond_stack)
#define COND_P()	BITSTACK_SET_P(cond_stack)

static stack_type cmdarg_stack = 0;
#define CMDARG_PUSH(n)	BITSTACK_PUSH(cmdarg_stack, n)
#define CMDARG_POP()	BITSTACK_POP(cmdarg_stack)
#define CMDARG_LEXPOP()	BITSTACK_LEXPOP(cmdarg_stack)
#define CMDARG_P()	BITSTACK_SET_P(cmdarg_stack)

static int class_nest = 0;
static int in_single = 0;
static int in_def = 0;
static int compile_for_eval = 0;
static ID cur_mid = 0;
static int command_start = Qtrue;

static NODE *cond();
static NODE *logop();
static int cond_negative();

static NODE *newline_node();
static void fixpos();

static int value_expr0();
static void void_expr0();
static void void_stmts();
static NODE *remove_begin();
#define value_expr(node) value_expr0((node) = remove_begin(node))
#define void_expr(node) void_expr0((node) = remove_begin(node))

static NODE *block_append();
static NODE *list_append();
static NODE *list_concat();
static NODE *arg_concat();
static NODE *arg_prepend();
static NODE *literal_concat();
static NODE *new_evstr();
static NODE *evstr2dstr();
static NODE *call_op();
static int in_defined = 0;

static NODE *negate_lit();
static NODE *ret_args();
static NODE *arg_blk_pass();
static NODE *new_call();
static NODE *new_fcall();
static NODE *new_super();
static NODE *new_yield();

static NODE *gettable();
static NODE *assignable();
static NODE *aryset();
static NODE *attrset();
static void rb_backref_error();
static NODE *node_assign();

static NODE *match_gen();
static void local_push();
static void local_pop();
static int  local_append();
static int  local_cnt();
static int  local_id();
static ID  *local_tbl();
static ID   internal_id();

static struct RVarmap *dyna_push();
static void dyna_pop();
static int dyna_in_block();
static NODE *dyna_init();

static void top_local_init();
static void top_local_setup();

#define RE_OPTION_ONCE 0x80

#define NODE_STRTERM NODE_ZARRAY	/* nothing to gc */
#define NODE_HEREDOC NODE_ARRAY 	/* 1, 3 to gc */
#define SIGN_EXTEND(x,n) (((1&lt;&lt;(n)-1)^((x)&amp;~(~0&lt;&lt;(n))))-(1&lt;&lt;(n)-1))
#define nd_func u1.id
#if SIZEOF_SHORT == 2
#define nd_term(node) ((signed short)(node)-&gt;u2.id)
#else
#define nd_term(node) SIGN_EXTEND((node)-&gt;u2.id, CHAR_BIT*2)
#endif
#define nd_paren(node) (char)((node)-&gt;u2.id &gt;&gt; CHAR_BIT*2)
#define nd_nest u3.id

/* Older versions of Yacc set YYMAXDEPTH to a very low value by default (150,
   for instance).  This is too low for Ruby to parse some files, such as
   date/format.rb, therefore bump the value up to at least Bison's default. */
#ifdef OLD_YACC
#ifndef YYMAXDEPTH
#define YYMAXDEPTH 10000
#endif
#endif

%}

%union {
    NODE *node;
    ID id;
    int num;
    struct RVarmap *vars;
}

%token  kCLASS
	kMODULE
	kDEF
	kUNDEF
	kBEGIN
	kRESCUE
	kENSURE
	kEND
	kIF
	kUNLESS
	kTHEN
	kELSIF
	kELSE
	kCASE
	kWHEN
	kWHILE
	kUNTIL
	kFOR
	kBREAK
	kNEXT
	kREDO
	kRETRY
	kIN
	kDO
	kDO_COND
	kDO_BLOCK
	kRETURN
	kYIELD
	kSUPER
	kSELF
	kNIL
	kTRUE
	kFALSE
	kAND
	kOR
	kNOT
	kIF_MOD
	kUNLESS_MOD
	kWHILE_MOD
	kUNTIL_MOD
	kRESCUE_MOD
	kALIAS
	kDEFINED
	klBEGIN
	klEND
	k__LINE__
	k__FILE__

%token &lt;id&gt;   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR
%token &lt;node&gt; tINTEGER tFLOAT tSTRING_CONTENT
%token &lt;node&gt; tNTH_REF tBACK_REF
%token &lt;num&gt;  tREGEXP_END

%type &lt;node&gt; singleton strings string string1 xstring regexp
%type &lt;node&gt; string_contents xstring_contents string_content
%type &lt;node&gt; words qwords word_list qword_list word
%type &lt;node&gt; literal numeric dsym cpath
%type &lt;node&gt; bodystmt compstmt stmts stmt expr arg primary command command_call method_call
%type &lt;node&gt; expr_value arg_value primary_value
%type &lt;node&gt; if_tail opt_else case_body cases opt_rescue exc_list exc_var opt_ensure
%type &lt;node&gt; args when_args call_args call_args2 open_args paren_args opt_paren_args
%type &lt;node&gt; command_args aref_args opt_block_arg block_arg var_ref var_lhs
%type &lt;node&gt; mrhs superclass block_call block_command
%type &lt;node&gt; f_arglist f_args f_optarg f_opt f_rest_arg f_block_arg opt_f_block_arg
%type &lt;node&gt; assoc_list assocs assoc undef_list backref string_dvar
%type &lt;node&gt; block_var opt_block_var brace_block cmd_brace_block do_block lhs none fitem
%type &lt;node&gt; mlhs mlhs_head mlhs_basic mlhs_entry mlhs_item mlhs_node
%type &lt;id&gt;   fsym variable sym symbol operation operation2 operation3
%type &lt;id&gt;   cname fname op
%type &lt;num&gt;  f_norm_arg f_arg
%token tUPLUS 		/* unary+ */
%token tUMINUS 		/* unary- */
%token tPOW		/* ** */
%token tCMP  		/* &lt;=&gt; */
%token tEQ  		/* == */
%token tEQQ  		/* === */
%token tNEQ  		/* != */
%token tGEQ  		/* &gt;= */
%token tLEQ  		/* &lt;= */
%token tANDOP tOROP	/* &amp;&amp; and || */
%token tMATCH tNMATCH	/* =~ and !~ */
%token tDOT2 tDOT3	/* .. and ... */
%token tAREF tASET	/* [] and []= */
%token tLSHFT tRSHFT	/* &lt;&lt; and &gt;&gt; */
%token tCOLON2		/* :: */
%token tCOLON3		/* :: at EXPR_BEG */
%token &lt;id&gt; tOP_ASGN	/* +=, -=  etc. */
%token tASSOC		/* =&gt; */
%token tLPAREN		/* ( */
%token tLPAREN_ARG	/* ( */
%token tRPAREN		/* ) */
%token tLBRACK		/* [ */
%token tLBRACE		/* { */
%token tLBRACE_ARG	/* { */
%token tSTAR		/* * */
%token tAMPER		/* &amp; */
%token tSYMBEG tSTRING_BEG tXSTRING_BEG tREGEXP_BEG tWORDS_BEG tQWORDS_BEG
%token tSTRING_DBEG tSTRING_DVAR tSTRING_END

/*
 *	precedence table
 */

%nonassoc tLOWEST
%nonassoc tLBRACE_ARG

%nonassoc  kIF_MOD kUNLESS_MOD kWHILE_MOD kUNTIL_MOD
%left  kOR kAND
%right kNOT
%nonassoc kDEFINED
%right '=' tOP_ASGN
%left kRESCUE_MOD
%right '?' ':'
%nonassoc tDOT2 tDOT3
%left  tOROP
%left  tANDOP
%nonassoc  tCMP tEQ tEQQ tNEQ tMATCH tNMATCH
%left  '&gt;' tGEQ '&lt;' tLEQ
%left  '|' '^'
%left  '&amp;'
%left  tLSHFT tRSHFT
%left  '+' '-'
%left  '*' '/' '%'
%right tUMINUS_NUM tUMINUS
%right tPOW
%right '!' '~' tUPLUS

%token tLAST_TOKEN

%%
program		:  {
			lex_state = EXPR_BEG;
                        top_local_init();
			if (ruby_class == rb_cObject) class_nest = 0;
			else class_nest = 1;
		    }
		  compstmt
		    {
			if ($2 &amp;&amp; !compile_for_eval) {
                            /* last expression should not be void */
			    if (nd_type($2) != NODE_BLOCK) void_expr($2);
			    else {
				NODE *node = $2;
				while (node-&gt;nd_next) {
				    node = node-&gt;nd_next;
				}
				void_expr(node-&gt;nd_head);
			    }
			}
			ruby_eval_tree = block_append(ruby_eval_tree, $2);
                        top_local_setup();
			class_nest = 0;
		    }
		;

bodystmt	: compstmt
		  opt_rescue
		  opt_else
		  opt_ensure
		    {
		        $$ = $1;
			if ($2) {
			    $$ = NEW_RESCUE($1, $2, $3);
			}
			else if ($3) {
			    rb_warn(&quot;else without rescue is useless&quot;);
			    $$ = block_append($$, $3);
			}
			if ($4) {
			    $$ = NEW_ENSURE($$, $4);
			}
			fixpos($$, $1);
		    }
		;

compstmt	: stmts opt_terms
		    {
			void_stmts($1);
		        $$ = $1;
		    }
		;

stmts		: none
		| stmt
		    {
			$$ = newline_node($1);
		    }
		| stmts terms stmt
		    {
			$$ = block_append($1, newline_node($3));
		    }
		| error stmt
		    {
			$$ = remove_begin($2);
		    }
		;

stmt		: kALIAS fitem {lex_state = EXPR_FNAME;} fitem
		    {
		        $$ = NEW_ALIAS($2, $4);
		    }
		| kALIAS tGVAR tGVAR
		    {
		        $$ = NEW_VALIAS($2, $3);
		    }
		| kALIAS tGVAR tBACK_REF
		    {
			char buf[3];

			sprintf(buf, &quot;$%c&quot;, (char)$3-&gt;nd_nth);
		        $$ = NEW_VALIAS($2, rb_intern(buf));
		    }
		| kALIAS tGVAR tNTH_REF
		    {
		        yyerror(&quot;can't make alias for the number variables&quot;);
		        $$ = 0;
		    }
		| kUNDEF undef_list
		    {
			$$ = $2;
		    }
		| stmt kIF_MOD expr_value
		    {
			$$ = NEW_IF(cond($3), remove_begin($1), 0);
		        fixpos($$, $3);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
		            $$-&gt;nd_else = $$-&gt;nd_body;
		            $$-&gt;nd_body = 0;
			}
		    }
		| stmt kUNLESS_MOD expr_value
		    {
			$$ = NEW_UNLESS(cond($3), remove_begin($1), 0);
		        fixpos($$, $3);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
		            $$-&gt;nd_body = $$-&gt;nd_else;
		            $$-&gt;nd_else = 0;
			}
		    }
		| stmt kWHILE_MOD expr_value
		    {
			if ($1 &amp;&amp; nd_type($1) == NODE_BEGIN) {
			    $$ = NEW_WHILE(cond($3), $1-&gt;nd_body, 0);
			}
			else {
			    $$ = NEW_WHILE(cond($3), $1, 1);
			}
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
			    nd_set_type($$, NODE_UNTIL);
			}
		    }
		| stmt kUNTIL_MOD expr_value
		    {
			if ($1 &amp;&amp; nd_type($1) == NODE_BEGIN) {
			    $$ = NEW_UNTIL(cond($3), $1-&gt;nd_body, 0);
			}
			else {
			    $$ = NEW_UNTIL(cond($3), $1, 1);
			}
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
			    nd_set_type($$, NODE_WHILE);
			}
		    }
		| stmt kRESCUE_MOD stmt
		    {
			NODE *resq = NEW_RESBODY(0, remove_begin($3), 0);
			$$ = NEW_RESCUE(remove_begin($1), resq, 0);
		    }
		| klBEGIN
		    {
			if (in_def || in_single) {
			    yyerror(&quot;BEGIN in method&quot;);
			}
			local_push(0);
		    }
		  '{' compstmt '}'
		    {
			ruby_eval_tree_begin = block_append(ruby_eval_tree_begin,
						            NEW_PREEXE($4));
		        local_pop();
		        $$ = 0;
		    }
		| klEND '{' compstmt '}'
		    {
			if (in_def || in_single) {
			    rb_warn(&quot;END in method; use at_exit&quot;);
			}

			$$ = NEW_ITER(0, NEW_POSTEXE(), $3);
		    }
		| lhs '=' command_call
		    {
			$$ = node_assign($1, $3);
		    }
		| mlhs '=' command_call
		    {
			value_expr($3);
			$1-&gt;nd_value = ($1-&gt;nd_head) ? NEW_TO_ARY($3) : NEW_ARRAY($3);
			$$ = $1;
		    }
		| var_lhs tOP_ASGN command_call
		    {
			value_expr($3);
			if ($1) {
			    ID vid = $1-&gt;nd_vid;
			    if ($2 == tOROP) {
				$1-&gt;nd_value = $3;
				$$ = NEW_OP_ASGN_OR(gettable(vid), $1);
				if (is_asgn_or_id(vid)) {
				    $$-&gt;nd_aid = vid;
				}
			    }
			    else if ($2 == tANDOP) {
				$1-&gt;nd_value = $3;
				$$ = NEW_OP_ASGN_AND(gettable(vid), $1);
			    }
			    else {
				$$ = $1;
				$$-&gt;nd_value = call_op(gettable(vid),$2,1,$3);
			    }
			}
			else {
			    $$ = 0;
			}
		    }
		| primary_value '[' aref_args ']' tOP_ASGN command_call
		    {
                        NODE *args;

			value_expr($6);
			if (!$3) $3 = NEW_ZARRAY();
			args = arg_concat($6, $3);
			if ($5 == tOROP) {
			    $5 = 0;
			}
			else if ($5 == tANDOP) {
			    $5 = 1;
			}
			$$ = NEW_OP_ASGN1($1, $5, args);
		        fixpos($$, $1);
		    }
		| primary_value '.' tIDENTIFIER tOP_ASGN command_call
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| primary_value '.' tCONSTANT tOP_ASGN command_call
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 tIDENTIFIER tOP_ASGN command_call
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| backref tOP_ASGN command_call
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		| lhs '=' mrhs
		    {
			$$ = node_assign($1, NEW_SVALUE($3));
		    }
		| mlhs '=' arg_value
		    {
			$1-&gt;nd_value = ($1-&gt;nd_head) ? NEW_TO_ARY($3) : NEW_ARRAY($3);
			$$ = $1;
		    }
		| mlhs '=' mrhs
		    {
			$1-&gt;nd_value = $3;
			$$ = $1;
		    }
		| expr
		;

expr		: command_call
		| expr kAND expr
		    {
			$$ = logop(NODE_AND, $1, $3);
		    }
		| expr kOR expr
		    {
			$$ = logop(NODE_OR, $1, $3);
		    }
		| kNOT expr
		    {
			$$ = NEW_NOT(cond($2));
		    }
		| '!' command_call
		    {
			$$ = NEW_NOT(cond($2));
		    }
		| arg
		;

expr_value	: expr
		    {
			value_expr($$);
			$$ = $1;
		    }
		;

command_call	: command
		| block_command
		| kRETURN call_args
		    {
			$$ = NEW_RETURN(ret_args($2));
		    }
		| kBREAK call_args
		    {
			$$ = NEW_BREAK(ret_args($2));
		    }
		| kNEXT call_args
		    {
			$$ = NEW_NEXT(ret_args($2));
		    }
		;

block_command	: block_call
		| block_call '.' operation2 command_args
		    {
			$$ = new_call($1, $3, $4);
		    }
		| block_call tCOLON2 operation2 command_args
		    {
			$$ = new_call($1, $3, $4);
		    }
		;

cmd_brace_block	: tLBRACE_ARG
		    {
			$&lt;vars&gt;$ = dyna_push();
			$&lt;num&gt;1 = ruby_sourceline;
		    }
		  opt_block_var {$&lt;vars&gt;$ = ruby_dyna_vars;}
		  compstmt
		  '}'
		    {
			$$ = NEW_ITER($3, 0, dyna_init($5, $&lt;vars&gt;4));
			nd_set_line($$, $&lt;num&gt;1);
			dyna_pop($&lt;vars&gt;2);
		    }
		;

command		: operation command_args       %prec tLOWEST
		    {
			$$ = new_fcall($1, $2);
		        fixpos($$, $2);
		   }
		| operation command_args cmd_brace_block
		    {
			$$ = new_fcall($1, $2);
			if ($3) {
			    if (nd_type($$) == NODE_BLOCK_PASS) {
				rb_compile_error(&quot;both block arg and actual block given&quot;);
			    }
			    $3-&gt;nd_iter = $$;
			    $$ = $3;
			}
		        fixpos($$, $2);
		   }
		| primary_value '.' operation2 command_args	%prec tLOWEST
		    {
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary_value '.' operation2 command_args cmd_brace_block
		    {
			$$ = new_call($1, $3, $4);
			if ($5) {
			    if (nd_type($$) == NODE_BLOCK_PASS) {
				rb_compile_error(&quot;both block arg and actual block given&quot;);
			    }
			    $5-&gt;nd_iter = $$;
			    $$ = $5;
			}
		        fixpos($$, $1);
		   }
		| primary_value tCOLON2 operation2 command_args	%prec tLOWEST
		    {
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 operation2 command_args cmd_brace_block
		    {
			$$ = new_call($1, $3, $4);
			if ($5) {
			    if (nd_type($$) == NODE_BLOCK_PASS) {
				rb_compile_error(&quot;both block arg and actual block given&quot;);
			    }
			    $5-&gt;nd_iter = $$;
			    $$ = $5;
			}
		        fixpos($$, $1);
		   }
		| kSUPER command_args
		    {
			$$ = new_super($2);
		        fixpos($$, $2);
		    }
		| kYIELD command_args
		    {
			$$ = new_yield($2);
		        fixpos($$, $2);
		    }
		;

mlhs		: mlhs_basic
		| tLPAREN mlhs_entry ')'
		    {
			$$ = $2;
		    }
		;

mlhs_entry	: mlhs_basic
		| tLPAREN mlhs_entry ')'
		    {
			$$ = NEW_MASGN(NEW_LIST($2), 0);
		    }
		;

mlhs_basic	: mlhs_head
		    {
			$$ = NEW_MASGN($1, 0);
		    }
		| mlhs_head mlhs_item
		    {
			$$ = NEW_MASGN(list_append($1,$2), 0);
		    }
		| mlhs_head tSTAR mlhs_node
		    {
			$$ = NEW_MASGN($1, $3);
		    }
		| mlhs_head tSTAR
		    {
			$$ = NEW_MASGN($1, -1);
		    }
		| tSTAR mlhs_node
		    {
			$$ = NEW_MASGN(0, $2);
		    }
		| tSTAR
		    {
			$$ = NEW_MASGN(0, -1);
		    }
		;

mlhs_item	: mlhs_node
		| tLPAREN mlhs_entry ')'
		    {
			$$ = $2;
		    }
		;

mlhs_head	: mlhs_item ','
		    {
			$$ = NEW_LIST($1);
		    }
		| mlhs_head mlhs_item ','
		    {
			$$ = list_append($1, $2);
		    }
		;

mlhs_node	: variable
		    {
			$$ = assignable($1, 0);
		    }
		| primary_value '[' aref_args ']'
		    {
			$$ = aryset($1, $3);
		    }
		| primary_value '.' tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value tCOLON2 tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value '.' tCONSTANT
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value tCOLON2 tCONSTANT
		    {
			if (in_def || in_single)
			    yyerror(&quot;dynamic constant assignment&quot;);
			$$ = NEW_CDECL(0, 0, NEW_COLON2($1, $3));
		    }
		| tCOLON3 tCONSTANT
		    {
			if (in_def || in_single)
			    yyerror(&quot;dynamic constant assignment&quot;);
			$$ = NEW_CDECL(0, 0, NEW_COLON3($2));
		    }
		| backref
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		;

lhs		: variable
		    {
			$$ = assignable($1, 0);
		    }
		| primary_value '[' aref_args ']'
		    {
			$$ = aryset($1, $3);
		    }
		| primary_value '.' tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value tCOLON2 tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value '.' tCONSTANT
		    {
			$$ = attrset($1, $3);
		    }
		| primary_value tCOLON2 tCONSTANT
		    {
			if (in_def || in_single)
			    yyerror(&quot;dynamic constant assignment&quot;);
			$$ = NEW_CDECL(0, 0, NEW_COLON2($1, $3));
		    }
		| tCOLON3 tCONSTANT
		    {
			if (in_def || in_single)
			    yyerror(&quot;dynamic constant assignment&quot;);
			$$ = NEW_CDECL(0, 0, NEW_COLON3($2));
		    }
		| backref
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		;

cname		: tIDENTIFIER
		    {
			yyerror(&quot;class/module name must be CONSTANT&quot;);
		    }
		| tCONSTANT
		;

cpath		: tCOLON3 cname
		    {
			$$ = NEW_COLON3($2);
		    }
		| cname
		    {
			$$ = NEW_COLON2(0, $$);
		    }
		| primary_value tCOLON2 cname
		    {
			$$ = NEW_COLON2($1, $3);
		    }
		;

fname		: tIDENTIFIER
		| tCONSTANT
		| tFID
		| op
		    {
			lex_state = EXPR_END;
			$$ = $1;
		    }
		| reswords
		    {
			lex_state = EXPR_END;
			$$ = $&lt;id&gt;1;
		    }
		;

fsym		: fname
		| symbol
		;

fitem		: fsym
		    {
			$$ = NEW_LIT(ID2SYM($1));
		    }
		| dsym
		;

undef_list	: fitem
		    {
			$$ = NEW_UNDEF($1);
		    }
		| undef_list ',' {lex_state = EXPR_FNAME;} fitem
		    {
			$$ = block_append($1, NEW_UNDEF($4));
		    }
		;

op		: '|'		{ $$ = '|'; }
		| '^'		{ $$ = '^'; }
		| '&amp;'		{ $$ = '&amp;'; }
		| tCMP		{ $$ = tCMP; }
		| tEQ		{ $$ = tEQ; }
		| tEQQ		{ $$ = tEQQ; }
		| tMATCH	{ $$ = tMATCH; }
		| '&gt;'		{ $$ = '&gt;'; }
		| tGEQ		{ $$ = tGEQ; }
		| '&lt;'		{ $$ = '&lt;'; }
		| tLEQ		{ $$ = tLEQ; }
		| tLSHFT	{ $$ = tLSHFT; }
		| tRSHFT	{ $$ = tRSHFT; }
		| '+'		{ $$ = '+'; }
		| '-'		{ $$ = '-'; }
		| '*'		{ $$ = '*'; }
		| tSTAR		{ $$ = '*'; }
		| '/'		{ $$ = '/'; }
		| '%'		{ $$ = '%'; }
		| tPOW		{ $$ = tPOW; }
		| '~'		{ $$ = '~'; }
		| tUPLUS	{ $$ = tUPLUS; }
		| tUMINUS	{ $$ = tUMINUS; }
		| tAREF		{ $$ = tAREF; }
		| tASET		{ $$ = tASET; }
		| '`'		{ $$ = '`'; }
		;

reswords	: k__LINE__ | k__FILE__  | klBEGIN | klEND
		| kALIAS | kAND | kBEGIN | kBREAK | kCASE | kCLASS | kDEF
		| kDEFINED | kDO | kELSE | kELSIF | kEND | kENSURE | kFALSE
		| kFOR | kIN | kMODULE | kNEXT | kNIL | kNOT
		| kOR | kREDO | kRESCUE | kRETRY | kRETURN | kSELF | kSUPER
		| kTHEN | kTRUE | kUNDEF | kWHEN | kYIELD
		| kIF | kUNLESS | kWHILE | kUNTIL
		;

arg		: lhs '=' arg
		    {
			$$ = node_assign($1, $3);
		    }
		| lhs '=' arg kRESCUE_MOD arg
		    {
			$$ = node_assign($1, NEW_RESCUE($3, NEW_RESBODY(0,$5,0), 0));
		    }
		| var_lhs tOP_ASGN arg
		    {
			value_expr($3);
			if ($1) {
			    ID vid = $1-&gt;nd_vid;
			    if ($2 == tOROP) {
				$1-&gt;nd_value = $3;
				$$ = NEW_OP_ASGN_OR(gettable(vid), $1);
				if (is_asgn_or_id(vid)) {
				    $$-&gt;nd_aid = vid;
				}
			    }
			    else if ($2 == tANDOP) {
				$1-&gt;nd_value = $3;
				$$ = NEW_OP_ASGN_AND(gettable(vid), $1);
			    }
			    else {
				$$ = $1;
				$$-&gt;nd_value = call_op(gettable(vid),$2,1,$3);
			    }
			}
			else {
			    $$ = 0;
			}
		    }
		| primary_value '[' aref_args ']' tOP_ASGN arg
		    {
                        NODE *args;

			value_expr($6);
			if (!$3) $3 = NEW_ZARRAY();
			args = arg_concat($6, $3);
			if ($5 == tOROP) {
			    $5 = 0;
			}
			else if ($5 == tANDOP) {
			    $5 = 1;
			}
			$$ = NEW_OP_ASGN1($1, $5, args);
		        fixpos($$, $1);
		    }
		| primary_value '.' tIDENTIFIER tOP_ASGN arg
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| primary_value '.' tCONSTANT tOP_ASGN arg
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 tIDENTIFIER tOP_ASGN arg
		    {
			value_expr($5);
			if ($4 == tOROP) {
			    $4 = 0;
			}
			else if ($4 == tANDOP) {
			    $4 = 1;
			}
			$$ = NEW_OP_ASGN2($1, $3, $4, $5);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 tCONSTANT tOP_ASGN arg
		    {
			yyerror(&quot;constant re-assignment&quot;);
			$$ = 0;
		    }
		| tCOLON3 tCONSTANT tOP_ASGN arg
		    {
			yyerror(&quot;constant re-assignment&quot;);
			$$ = 0;
		    }
		| backref tOP_ASGN arg
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		| arg tDOT2 arg
		    {
			value_expr($1);
			value_expr($3);
			if (nd_type($1) == NODE_LIT &amp;&amp; FIXNUM_P($1-&gt;nd_lit) &amp;&amp;
			    nd_type($3) == NODE_LIT &amp;&amp; FIXNUM_P($3-&gt;nd_lit)) {
			    $1-&gt;nd_lit = rb_range_new($1-&gt;nd_lit, $3-&gt;nd_lit, Qfalse);
			    $$ = $1;
			}
			else {
			    $$ = NEW_DOT2($1, $3);
			}
		    }
		| arg tDOT3 arg
		    {
			value_expr($1);
			value_expr($3);
			if (nd_type($1) == NODE_LIT &amp;&amp; FIXNUM_P($1-&gt;nd_lit) &amp;&amp;
			    nd_type($3) == NODE_LIT &amp;&amp; FIXNUM_P($3-&gt;nd_lit)) {
			    $1-&gt;nd_lit = rb_range_new($1-&gt;nd_lit, $3-&gt;nd_lit, Qtrue);
			    $$ = $1;
			}
			else {
			    $$ = NEW_DOT3($1, $3);
			}
		    }
		| arg '+' arg
		    {
			$$ = call_op($1, '+', 1, $3);
		    }
		| arg '-' arg
		    {
		        $$ = call_op($1, '-', 1, $3);
		    }
		| arg '*' arg
		    {
		        $$ = call_op($1, '*', 1, $3);
		    }
		| arg '/' arg
		    {
			$$ = call_op($1, '/', 1, $3);
		    }
		| arg '%' arg
		    {
			$$ = call_op($1, '%', 1, $3);
		    }
		| arg tPOW arg
		    {
			$$ = call_op($1, tPOW, 1, $3);
		    }
		| tUMINUS_NUM tINTEGER tPOW arg
		    {
			$$ = call_op(call_op($2, tPOW, 1, $4), tUMINUS, 0, 0);
		    }
		| tUMINUS_NUM tFLOAT tPOW arg
		    {
			$$ = call_op(call_op($2, tPOW, 1, $4), tUMINUS, 0, 0);
		    }
		| tUPLUS arg
		    {
			if ($2 &amp;&amp; nd_type($2) == NODE_LIT) {
			    $$ = $2;
			}
			else {
			    $$ = call_op($2, tUPLUS, 0, 0);
			}
		    }
		| tUMINUS arg
		    {
			$$ = call_op($2, tUMINUS, 0, 0);
		    }
		| arg '|' arg
		    {
		        $$ = call_op($1, '|', 1, $3);
		    }
		| arg '^' arg
		    {
			$$ = call_op($1, '^', 1, $3);
		    }
		| arg '&amp;' arg
		    {
			$$ = call_op($1, '&amp;', 1, $3);
		    }
		| arg tCMP arg
		    {
			$$ = call_op($1, tCMP, 1, $3);
		    }
		| arg '&gt;' arg
		    {
			$$ = call_op($1, '&gt;', 1, $3);
		    }
		| arg tGEQ arg
		    {
			$$ = call_op($1, tGEQ, 1, $3);
		    }
		| arg '&lt;' arg
		    {
			$$ = call_op($1, '&lt;', 1, $3);
		    }
		| arg tLEQ arg
		    {
			$$ = call_op($1, tLEQ, 1, $3);
		    }
		| arg tEQ arg
		    {
			$$ = call_op($1, tEQ, 1, $3);
		    }
		| arg tEQQ arg
		    {
			$$ = call_op($1, tEQQ, 1, $3);
		    }
		| arg tNEQ arg
		    {
			$$ = NEW_NOT(call_op($1, tEQ, 1, $3));
		    }
		| arg tMATCH arg
		    {
			$$ = match_gen($1, $3);
		    }
		| arg tNMATCH arg
		    {
			$$ = NEW_NOT(match_gen($1, $3));
		    }
		| '!' arg
		    {
			$$ = NEW_NOT(cond($2));
		    }
		| '~' arg
		    {
			$$ = call_op($2, '~', 0, 0);
		    }
		| arg tLSHFT arg
		    {
			$$ = call_op($1, tLSHFT, 1, $3);
		    }
		| arg tRSHFT arg
		    {
			$$ = call_op($1, tRSHFT, 1, $3);
		    }
		| arg tANDOP arg
		    {
			$$ = logop(NODE_AND, $1, $3);
		    }
		| arg tOROP arg
		    {
			$$ = logop(NODE_OR, $1, $3);
		    }
		| kDEFINED opt_nl {in_defined = 1;} arg
		    {
		        in_defined = 0;
			$$ = NEW_DEFINED($4);
		    }
		| arg '?' arg ':' arg
		    {
			$$ = NEW_IF(cond($1), $3, $5);
		        fixpos($$, $1);
		    }
		| primary
		    {
			$$ = $1;
		    }
		;

arg_value	: arg
		    {
			value_expr($1);
			$$ = $1;
		    }
		;

aref_args	: none
		| command opt_nl
		    {
		        rb_warn(&quot;parenthesize argument(s) for future version&quot;);
			$$ = NEW_LIST($1);
		    }
		| args trailer
		    {
			$$ = $1;
		    }
		| args ',' tSTAR arg opt_nl
		    {
			value_expr($4);
			$$ = arg_concat($1, $4);
		    }
		| assocs trailer
		    {
			$$ = NEW_LIST(NEW_HASH($1));
		    }
		| tSTAR arg opt_nl
		    {
			value_expr($2);
			$$ = NEW_NEWLINE(NEW_SPLAT($2));
		    }
		;

paren_args	: '(' none ')'
		    {
			$$ = $2;
		    }
		| '(' call_args opt_nl ')'
		    {
			$$ = $2;
		    }
		| '(' block_call opt_nl ')'
		    {
		        rb_warn(&quot;parenthesize argument for future version&quot;);
			$$ = NEW_LIST($2);
		    }
		| '(' args ',' block_call opt_nl ')'
		    {
		        rb_warn(&quot;parenthesize argument for future version&quot;);
			$$ = list_append($2, $4);
		    }
		;

opt_paren_args	: none
		| paren_args
		;

call_args	: command
		    {
		        rb_warn(&quot;parenthesize argument(s) for future version&quot;);
			$$ = NEW_LIST($1);
		    }
		| args opt_block_arg
		    {
			$$ = arg_blk_pass($1, $2);
		    }
		| args ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat($1, $4);
			$$ = arg_blk_pass($$, $5);
		    }
		| assocs opt_block_arg
		    {
			$$ = NEW_LIST(NEW_HASH($1));
			$$ = arg_blk_pass($$, $2);
		    }
		| assocs ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat(NEW_LIST(NEW_HASH($1)), $4);
			$$ = arg_blk_pass($$, $5);
		    }
		| args ',' assocs opt_block_arg
		    {
			$$ = list_append($1, NEW_HASH($3));
			$$ = arg_blk_pass($$, $4);
		    }
		| args ',' assocs ',' tSTAR arg opt_block_arg
		    {
			value_expr($6);
			$$ = arg_concat(list_append($1, NEW_HASH($3)), $6);
			$$ = arg_blk_pass($$, $7);
		    }
		| tSTAR arg_value opt_block_arg
		    {
			$$ = arg_blk_pass(NEW_SPLAT($2), $3);
		    }
		| block_arg
		;

call_args2	: arg_value ',' args opt_block_arg
		    {
			$$ = arg_blk_pass(list_concat(NEW_LIST($1),$3), $4);
		    }
		| arg_value ',' block_arg
		    {
                        $$ = arg_blk_pass($1, $3);
                    }
		| arg_value ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat(NEW_LIST($1), $4);
			$$ = arg_blk_pass($$, $5);
		    }
		| arg_value ',' args ',' tSTAR arg_value opt_block_arg
		    {
                       $$ = arg_concat(list_concat(NEW_LIST($1),$3), $6);
			$$ = arg_blk_pass($$, $7);
		    }
		| assocs opt_block_arg
		    {
			$$ = NEW_LIST(NEW_HASH($1));
			$$ = arg_blk_pass($$, $2);
		    }
		| assocs ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat(NEW_LIST(NEW_HASH($1)), $4);
			$$ = arg_blk_pass($$, $5);
		    }
		| arg_value ',' assocs opt_block_arg
		    {
			$$ = list_append(NEW_LIST($1), NEW_HASH($3));
			$$ = arg_blk_pass($$, $4);
		    }
		| arg_value ',' args ',' assocs opt_block_arg
		    {
			$$ = list_append(list_concat(NEW_LIST($1),$3), NEW_HASH($5));
			$$ = arg_blk_pass($$, $6);
		    }
		| arg_value ',' assocs ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat(list_append(NEW_LIST($1), NEW_HASH($3)), $6);
			$$ = arg_blk_pass($$, $7);
		    }
		| arg_value ',' args ',' assocs ',' tSTAR arg_value opt_block_arg
		    {
			$$ = arg_concat(list_append(list_concat(NEW_LIST($1), $3), NEW_HASH($5)), $8);
			$$ = arg_blk_pass($$, $9);
		    }
		| tSTAR arg_value opt_block_arg
		    {
			$$ = arg_blk_pass(NEW_SPLAT($2), $3);
		    }
		| block_arg
		;

command_args	:  {
			$&lt;num&gt;$ = cmdarg_stack;
			CMDARG_PUSH(1);
		    }
		  open_args
		    {
			/* CMDARG_POP() */
		        cmdarg_stack = $&lt;num&gt;1;
			$$ = $2;
		    }
		;

open_args	: call_args
		| tLPAREN_ARG  {lex_state = EXPR_ENDARG;} ')'
		    {
		        rb_warn(&quot;don't put space before argument parentheses&quot;);
			$$ = 0;
		    }
		| tLPAREN_ARG call_args2 {lex_state = EXPR_ENDARG;} ')'
		    {
		        rb_warn(&quot;don't put space before argument parentheses&quot;);
			$$ = $2;
		    }
		;

block_arg	: tAMPER arg_value
		    {
			$$ = NEW_BLOCK_PASS($2);
		    }
		;

opt_block_arg	: ',' block_arg
		    {
			$$ = $2;
		    }
		| none
		;

args 		: arg_value
		    {
			$$ = NEW_LIST($1);
		    }
		| args ',' arg_value
		    {
			$$ = list_append($1, $3);
		    }
		;

mrhs		: args ',' arg_value
		    {
			$$ = list_append($1, $3);
		    }
		| args ',' tSTAR arg_value
		    {
			$$ = arg_concat($1, $4);
		    }
		| tSTAR arg_value
		    {
			$$ = NEW_SPLAT($2);
		    }
		;

primary		: literal
		| strings
		| xstring
		| regexp
		| words
		| qwords
		| var_ref
		| backref
		| tFID
		    {
			$$ = NEW_FCALL($1, 0);
		    }
		| kBEGIN
		    {
			$&lt;num&gt;1 = ruby_sourceline;
		    }
		  bodystmt
		  kEND
		    {
			if ($3 == NULL)
			    $$ = NEW_NIL();
			else
			    $$ = NEW_BEGIN($3);
			nd_set_line($$, $&lt;num&gt;1);
		    }
		| tLPAREN_ARG expr {lex_state = EXPR_ENDARG;} opt_nl ')'
		    {
		        rb_warning(&quot;(...) interpreted as grouped expression&quot;);
			$$ = $2;
		    }
		| tLPAREN compstmt ')'
		    {
			if (!$2) $$ = NEW_NIL();
			else $$ = $2;
		    }
		| primary_value tCOLON2 tCONSTANT
		    {
			$$ = NEW_COLON2($1, $3);
		    }
		| tCOLON3 tCONSTANT
		    {
			$$ = NEW_COLON3($2);
		    }
		| primary_value '[' aref_args ']'
		    {
			if ($1 &amp;&amp; nd_type($1) == NODE_SELF)
			    $$ = NEW_FCALL(tAREF, $3);
			else
			    $$ = NEW_CALL($1, tAREF, $3);
			fixpos($$, $1);
		    }
		| tLBRACK aref_args ']'
		    {
		        if ($2 == 0) {
			    $$ = NEW_ZARRAY(); /* zero length array*/
			}
			else {
			    $$ = $2;
			}
		    }
		| tLBRACE assoc_list '}'
		    {
			$$ = NEW_HASH($2);
		    }
		| kRETURN
		    {
			$$ = NEW_RETURN(0);
		    }
		| kYIELD '(' call_args ')'
		    {
			$$ = new_yield($3);
		    }
		| kYIELD '(' ')'
		    {
			$$ = NEW_YIELD(0, Qfalse);
		    }
		| kYIELD
		    {
			$$ = NEW_YIELD(0, Qfalse);
		    }
		| kDEFINED opt_nl '(' {in_defined = 1;} expr ')'
		    {
		        in_defined = 0;
			$$ = NEW_DEFINED($5);
		    }
		| operation brace_block
		    {
			$2-&gt;nd_iter = NEW_FCALL($1, 0);
			$$ = $2;
			fixpos($2-&gt;nd_iter, $2);
		    }
		| method_call
		| method_call brace_block
		    {
			if ($1 &amp;&amp; nd_type($1) == NODE_BLOCK_PASS) {
			    rb_compile_error(&quot;both block arg and actual block given&quot;);
			}
			$2-&gt;nd_iter = $1;
			$$ = $2;
		        fixpos($$, $1);
		    }
		| kIF expr_value then
		  compstmt
		  if_tail
		  kEND
		    {
			$$ = NEW_IF(cond($2), $4, $5);
		        fixpos($$, $2);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
		            NODE *tmp = $$-&gt;nd_body;
		            $$-&gt;nd_body = $$-&gt;nd_else;
		            $$-&gt;nd_else = tmp;
			}
		    }
		| kUNLESS expr_value then
		  compstmt
		  opt_else
		  kEND
		    {
			$$ = NEW_UNLESS(cond($2), $4, $5);
		        fixpos($$, $2);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
		            NODE *tmp = $$-&gt;nd_body;
		            $$-&gt;nd_body = $$-&gt;nd_else;
		            $$-&gt;nd_else = tmp;
			}
		    }
		| kWHILE {COND_PUSH(1);} expr_value do {COND_POP();}
		  compstmt
		  kEND
		    {
			$$ = NEW_WHILE(cond($3), $6, 1);
		        fixpos($$, $3);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
			    nd_set_type($$, NODE_UNTIL);
			}
		    }
		| kUNTIL {COND_PUSH(1);} expr_value do {COND_POP();}
		  compstmt
		  kEND
		    {
			$$ = NEW_UNTIL(cond($3), $6, 1);
		        fixpos($$, $3);
			if (cond_negative(&amp;$$-&gt;nd_cond)) {
			    nd_set_type($$, NODE_WHILE);
			}
		    }
		| kCASE expr_value opt_terms
		  case_body
		  kEND
		    {
			$$ = NEW_CASE($2, $4);
		        fixpos($$, $2);
		    }
		| kCASE opt_terms case_body kEND
		    {
			$$ = $3;
		    }
		| kCASE opt_terms kELSE compstmt kEND
		    {
			$$ = $4;
		    }
		| kFOR block_var kIN {COND_PUSH(1);} expr_value do {COND_POP();}
		  compstmt
		  kEND
		    {
			$$ = NEW_FOR($2, $5, $8);
		        fixpos($$, $2);
		    }
		| kCLASS cpath superclass
		    {
			if (in_def || in_single)
			    yyerror(&quot;class definition in method body&quot;);
			class_nest++;
			local_push(0);
		        $&lt;num&gt;$ = ruby_sourceline;
		    }
		  bodystmt
		  kEND
		    {
		        $$ = NEW_CLASS($2, $5, $3);
		        nd_set_line($$, $&lt;num&gt;4);
		        local_pop();
			class_nest--;
		    }
		| kCLASS tLSHFT expr
		    {
			$&lt;num&gt;$ = in_def;
		        in_def = 0;
		    }
		  term
		    {
		        $&lt;num&gt;$ = in_single;
		        in_single = 0;
			class_nest++;
			local_push(0);
		    }
		  bodystmt
		  kEND
		    {
		        $$ = NEW_SCLASS($3, $7);
		        fixpos($$, $3);
		        local_pop();
			class_nest--;
		        in_def = $&lt;num&gt;4;
		        in_single = $&lt;num&gt;6;
		    }
		| kMODULE cpath
		    {
			if (in_def || in_single)
			    yyerror(&quot;module definition in method body&quot;);
			class_nest++;
			local_push(0);
		        $&lt;num&gt;$ = ruby_sourceline;
		    }
		  bodystmt
		  kEND
		    {
		        $$ = NEW_MODULE($2, $4);
		        nd_set_line($$, $&lt;num&gt;3);
		        local_pop();
			class_nest--;
		    }
		| kDEF fname
		    {
			$&lt;id&gt;$ = cur_mid;
			cur_mid = $2;
			in_def++;
			local_push(0);
		    }
		  f_arglist
		  bodystmt
		  kEND
		    {
			if (!$5) $5 = NEW_NIL();
			$$ = NEW_DEFN($2, $4, $5, NOEX_PRIVATE);
		        fixpos($$, $4);
		        local_pop();
			in_def--;
			cur_mid = $&lt;id&gt;3;
		    }
		| kDEF singleton dot_or_colon {lex_state = EXPR_FNAME;} fname
		    {
			in_single++;
			local_push(0);
		        lex_state = EXPR_END; /* force for args */
		    }
		  f_arglist
		  bodystmt
		  kEND
		    {
			$$ = NEW_DEFS($2, $5, $7, $8);
		        fixpos($$, $2);
		        local_pop();
			in_single--;
		    }
		| kBREAK
		    {
			$$ = NEW_BREAK(0);
		    }
		| kNEXT
		    {
			$$ = NEW_NEXT(0);
		    }
		| kREDO
		    {
			$$ = NEW_REDO();
		    }
		| kRETRY
		    {
			$$ = NEW_RETRY();
		    }
		;

primary_value 	: primary
		    {
			value_expr($1);
			$$ = $1;
		    }
		;

then		: term
		| ':'
		| kTHEN
		| term kTHEN
		;

do		: term
		| ':'
		| kDO_COND
		;

if_tail		: opt_else
		| kELSIF expr_value then
		  compstmt
		  if_tail
		    {
			$$ = NEW_IF(cond($2), $4, $5);
		        fixpos($$, $2);
		    }
		;

opt_else	: none
		| kELSE compstmt
		    {
			$$ = $2;
		    }
		;

block_var	: lhs
		| mlhs
		;

opt_block_var	: none
		| '|' /* none */ '|'
		    {
			$$ = (NODE*)1;
		    }
		| tOROP
		    {
			$$ = (NODE*)1;
		    }
		| '|' block_var '|'
		    {
			$$ = $2;
		    }
		;

do_block	: kDO_BLOCK
		    {
		        $&lt;vars&gt;$ = dyna_push();
			$&lt;num&gt;1 = ruby_sourceline;
		    }
		  opt_block_var {$&lt;vars&gt;$ = ruby_dyna_vars;}
		  compstmt
		  kEND
		    {
			$$ = NEW_ITER($3, 0, dyna_init($5, $&lt;vars&gt;4));
			nd_set_line($$, $&lt;num&gt;1);
			dyna_pop($&lt;vars&gt;2);
		    }
		;

block_call	: command do_block
		    {
			if ($1 &amp;&amp; nd_type($1) == NODE_BLOCK_PASS) {
			    rb_compile_error(&quot;both block arg and actual block given&quot;);
			}
			$2-&gt;nd_iter = $1;
			$$ = $2;
		        fixpos($$, $1);
		    }
		| block_call '.' operation2 opt_paren_args
		    {
			$$ = new_call($1, $3, $4);
		    }
		| block_call tCOLON2 operation2 opt_paren_args
		    {
			$$ = new_call($1, $3, $4);
		    }
		;

method_call	: operation paren_args
		    {
			$$ = new_fcall($1, $2);
		        fixpos($$, $2);
		    }
		| primary_value '.' operation2 opt_paren_args
		    {
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 operation2 paren_args
		    {
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary_value tCOLON2 operation3
		    {
			$$ = new_call($1, $3, 0);
		    }
		| kSUPER paren_args
		    {
			$$ = new_super($2);
		    }
		| kSUPER
		    {
			$$ = NEW_ZSUPER();
		    }
		;

brace_block	: '{'
		    {
		        $&lt;vars&gt;$ = dyna_push();
			$&lt;num&gt;1 = ruby_sourceline;
		    }
		  opt_block_var {$&lt;vars&gt;$ = ruby_dyna_vars;}
		  compstmt '}'
		    {
			$$ = NEW_ITER($3, 0, dyna_init($5, $&lt;vars&gt;4));
			nd_set_line($$, $&lt;num&gt;1);
			dyna_pop($&lt;vars&gt;2);
		    }
		| kDO
		    {
		        $&lt;vars&gt;$ = dyna_push();
			$&lt;num&gt;1 = ruby_sourceline;
		    }
		  opt_block_var {$&lt;vars&gt;$ = ruby_dyna_vars;}
		  compstmt kEND
		    {
			$$ = NEW_ITER($3, 0, dyna_init($5, $&lt;vars&gt;4));
			nd_set_line($$, $&lt;num&gt;1);
			dyna_pop($&lt;vars&gt;2);
		    }
		;

case_body	: kWHEN when_args then
		  compstmt
		  cases
		    {
			$$ = NEW_WHEN($2, $4, $5);
		    }
		;
when_args	: args
		| args ',' tSTAR arg_value
		    {
			$$ = list_append($1, NEW_WHEN($4, 0, 0));
		    }
		| tSTAR arg_value
		    {
			$$ = NEW_LIST(NEW_WHEN($2, 0, 0));
		    }
		;

cases		: opt_else
		| case_body
		;

opt_rescue	: kRESCUE exc_list exc_var then
		  compstmt
		  opt_rescue
		    {
		        if ($3) {
		            $3 = node_assign($3, NEW_GVAR(rb_intern(&quot;$!&quot;)));
			    $5 = block_append($3, $5);
			}
			$$ = NEW_RESBODY($2, $5, $6);
		        fixpos($$, $2?$2:$5);
		    }
		| none
		;

exc_list	: arg_value
		    {
			$$ = NEW_LIST($1);
		    }
		| mrhs
		| none
		;

exc_var		: tASSOC lhs
		    {
			$$ = $2;
		    }
		| none
		;

opt_ensure	: kENSURE compstmt
		    {
			if ($2)
			    $$ = $2;
			else
			    /* place holder */
			    $$ = NEW_NIL();
		    }
		| none
		;

literal		: numeric
		| symbol
		    {
			$$ = NEW_LIT(ID2SYM($1));
		    }
		| dsym
		;

strings		: string
		    {
			NODE *node = $1;
			if (!node) {
			    node = NEW_STR(rb_str_new(0, 0));
			}
			else {
			    node = evstr2dstr(node);
			}
			$$ = node;
		    }
		;

string		: string1
		| string string1
		    {
			$$ = literal_concat($1, $2);
		    }
		;

string1		: tSTRING_BEG string_contents tSTRING_END
		    {
			$$ = $2;
		    }
		;

xstring		: tXSTRING_BEG xstring_contents tSTRING_END
		    {
			NODE *node = $2;
			if (!node) {
			    node = NEW_XSTR(rb_str_new(0, 0));
			}
			else {
			    switch (nd_type(node)) {
			      case NODE_STR:
				nd_set_type(node, NODE_XSTR);
				break;
			      case NODE_DSTR:
				nd_set_type(node, NODE_DXSTR);
				break;
			      default:
				node = NEW_NODE(NODE_DXSTR, rb_str_new(0, 0), 1, NEW_LIST(node));
				break;
			    }
			}
			$$ = node;
		    }
		;

regexp		: tREGEXP_BEG xstring_contents tREGEXP_END
		    {
			int options = $3;
			NODE *node = $2;
			if (!node) {
			    node = NEW_LIT(rb_reg_new(&quot;&quot;, 0, options &amp; ~RE_OPTION_ONCE));
			}
			else switch (nd_type(node)) {
			  case NODE_STR:
			    {
				VALUE src = node-&gt;nd_lit;
				nd_set_type(node, NODE_LIT);
				node-&gt;nd_lit = rb_reg_new(RSTRING(src)-&gt;ptr,
							  RSTRING(src)-&gt;len,
							  options &amp; ~RE_OPTION_ONCE);
			    }
			    break;
			  default:
			    node = NEW_NODE(NODE_DSTR, rb_str_new(0, 0), 1, NEW_LIST(node));
			  case NODE_DSTR:
			    if (options &amp; RE_OPTION_ONCE) {
				nd_set_type(node, NODE_DREGX_ONCE);
			    }
			    else {
				nd_set_type(node, NODE_DREGX);
			    }
			    node-&gt;nd_cflag = options &amp; ~RE_OPTION_ONCE;
			    break;
			}
			$$ = node;
		    }
		;

words		: tWORDS_BEG ' ' tSTRING_END
		    {
			$$ = NEW_ZARRAY();
		    }
		| tWORDS_BEG word_list tSTRING_END
		    {
			$$ = $2;
		    }
		;

word_list	: /* none */
		    {
			$$ = 0;
		    }
		| word_list word ' '
		    {
			$$ = list_append($1, evstr2dstr($2));
		    }
		;

word		: string_content
		| word string_content
		    {
			$$ = literal_concat($1, $2);
		    }
		;

qwords		: tQWORDS_BEG ' ' tSTRING_END
		    {
			$$ = NEW_ZARRAY();
		    }
		| tQWORDS_BEG qword_list tSTRING_END
		    {
			$$ = $2;
		    }
		;

qword_list	: /* none */
		    {
			$$ = 0;
		    }
		| qword_list tSTRING_CONTENT ' '
		    {
			$$ = list_append($1, $2);
		    }
		;

string_contents : /* none */
		    {
			$$ = 0;
		    }
		| string_contents string_content
		    {
			$$ = literal_concat($1, $2);
		    }
		;

xstring_contents: /* none */
		    {
			$$ = 0;
		    }
		| xstring_contents string_content
		    {
			$$ = literal_concat($1, $2);
		    }
		;

string_content	: tSTRING_CONTENT
		| tSTRING_DVAR
		    {
			$&lt;node&gt;$ = lex_strterm;
			lex_strterm = 0;
			lex_state = EXPR_BEG;
		    }
		  string_dvar
		    {
			lex_strterm = $&lt;node&gt;2;
		        $$ = NEW_EVSTR($3);
		    }
		| tSTRING_DBEG
		    {
			$&lt;node&gt;$ = lex_strterm;
			lex_strterm = 0;
			lex_state = EXPR_BEG;
			COND_PUSH(0);
			CMDARG_PUSH(0);
		    }
		  compstmt '}'
		    {
			lex_strterm = $&lt;node&gt;2;
			COND_LEXPOP();
			CMDARG_LEXPOP();
			if (($$ = $3) &amp;&amp; nd_type($$) == NODE_NEWLINE) {
			    $$ = $$-&gt;nd_next;
			    rb_gc_force_recycle((VALUE)$3);
			}
			$$ = new_evstr($$);
		    }
		;

string_dvar	: tGVAR {$$ = NEW_GVAR($1);}
		| tIVAR {$$ = NEW_IVAR($1);}
		| tCVAR {$$ = NEW_CVAR($1);}
		| backref
		;

symbol		: tSYMBEG sym
		    {
		        lex_state = EXPR_END;
			$$ = $2;
		    }
		;

sym		: fname
		| tIVAR
		| tGVAR
		| tCVAR
		;

dsym		: tSYMBEG xstring_contents tSTRING_END
		    {
		        lex_state = EXPR_END;
			if (!($$ = $2)) {
			    $$ = NEW_NIL();
			    yyerror(&quot;empty symbol literal&quot;);
			}
			else {
			    VALUE lit;

			    switch (nd_type($$)) {
			      case NODE_DSTR:
				nd_set_type($$, NODE_DSYM);
				break;
			      case NODE_STR:
				lit = $$-&gt;nd_lit;
				if (RSTRING(lit)-&gt;len == 0) {
				    yyerror(&quot;empty symbol literal&quot;);
				    break;
				}
				if (strlen(RSTRING(lit)-&gt;ptr) == RSTRING(lit)-&gt;len) {
				    $$-&gt;nd_lit = ID2SYM(rb_intern(RSTRING($$-&gt;nd_lit)-&gt;ptr));
				    nd_set_type($$, NODE_LIT);
				    break;
				}
				/* fall through */
			      default:
				$$ = NEW_NODE(NODE_DSYM, rb_str_new(0, 0), 1, NEW_LIST($$));
				break;
			    }
			}
		    }
		;

numeric		: tINTEGER
		| tFLOAT
		| tUMINUS_NUM tINTEGER	       %prec tLOWEST
		    {
			$$ = negate_lit($2);
		    }
		| tUMINUS_NUM tFLOAT	       %prec tLOWEST
		    {
			$$ = negate_lit($2);
		    }
		;

variable	: tIDENTIFIER
		| tIVAR
		| tGVAR
		| tCONSTANT
		| tCVAR
		| kNIL {$$ = kNIL;}
		| kSELF {$$ = kSELF;}
		| kTRUE {$$ = kTRUE;}
		| kFALSE {$$ = kFALSE;}
		| k__FILE__ {$$ = k__FILE__;}
		| k__LINE__ {$$ = k__LINE__;}
		;

var_ref		: variable
		    {
			$$ = gettable($1);
		    }
		;

var_lhs		: variable
		    {
			$$ = assignable($1, 0);
		    }
		;

backref		: tNTH_REF
		| tBACK_REF
		;

superclass	: term
		    {
			$$ = 0;
		    }
		| '&lt;'
		    {
			lex_state = EXPR_BEG;
		    }
		  expr_value term
		    {
			$$ = $3;
		    }
		| error term {yyerrok; $$ = 0;}
		;

f_arglist	: '(' f_args opt_nl ')'
		    {
			$$ = $2;
			lex_state = EXPR_BEG;
		        command_start = Qtrue;
		    }
		| f_args term
		    {
			$$ = $1;
		    }
		;

f_args		: f_arg ',' f_optarg ',' f_rest_arg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS($1, $3, $5), $6);
		    }
		| f_arg ',' f_optarg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS($1, $3, 0), $4);
		    }
		| f_arg ',' f_rest_arg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS($1, 0, $3), $4);
		    }
		| f_arg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS($1, 0, 0), $2);
		    }
		| f_optarg ',' f_rest_arg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS(0, $1, $3), $4);
		    }
		| f_optarg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS(0, $1, 0), $2);
		    }
		| f_rest_arg opt_f_block_arg
		    {
			$$ = block_append(NEW_ARGS(0, 0, $1), $2);
		    }
		| f_block_arg
		    {
			$$ = block_append(NEW_ARGS(0, 0, 0), $1);
		    }
		| /* none */
		    {
			$$ = NEW_ARGS(0, 0, 0);
		    }
		;

f_norm_arg	: tCONSTANT
		    {
			yyerror(&quot;formal argument cannot be a constant&quot;);
		    }
                | tIVAR
		    {
                        yyerror(&quot;formal argument cannot be an instance variable&quot;);
		    }
                | tGVAR
		    {
                        yyerror(&quot;formal argument cannot be a global variable&quot;);
		    }
                | tCVAR
		    {
                        yyerror(&quot;formal argument cannot be a class variable&quot;);
		    }
		| tIDENTIFIER
		    {
			if (!is_local_id($1))
			    yyerror(&quot;formal argument must be local variable&quot;);
			else if (local_id($1))
			    yyerror(&quot;duplicate argument name&quot;);
			local_cnt($1);
			$$ = 1;
		    }
		;

f_arg		: f_norm_arg
		| f_arg ',' f_norm_arg
		    {
			$$ += 1;
		    }
		;

f_opt		: tIDENTIFIER '=' arg_value
		    {
			if (!is_local_id($1))
			    yyerror(&quot;formal argument must be local variable&quot;);
			else if (local_id($1))
			    yyerror(&quot;duplicate optional argument name&quot;);
			$$ = assignable($1, $3);
		    }
		;

f_optarg	: f_opt
		    {
			$$ = NEW_BLOCK($1);
			$$-&gt;nd_end = $$;
		    }
		| f_optarg ',' f_opt
		    {
			$$ = block_append($1, $3);
		    }
		;

restarg_mark	: '*'
		| tSTAR
		;

f_rest_arg	: restarg_mark tIDENTIFIER
		    {
			if (!is_local_id($2))
			    yyerror(&quot;rest argument must be local variable&quot;);
			else if (local_id($2))
			    yyerror(&quot;duplicate rest argument name&quot;);
			if (dyna_in_block()) {
			    rb_dvar_push($2, Qnil);
			}
			$$ = assignable($2, 0);
		    }
		| restarg_mark
		    {
			if (dyna_in_block()) {
			    $$ = NEW_DASGN_CURR(internal_id(), 0);
			}
			else {
			    $$ = NEW_NODE(NODE_LASGN,0,0,local_append(0));
			}
		    }
		;

blkarg_mark	: '&amp;'
		| tAMPER
		;

f_block_arg	: blkarg_mark tIDENTIFIER
		    {
			if (!is_local_id($2))
			    yyerror(&quot;block argument must be local variable&quot;);
			else if (local_id($2))
			    yyerror(&quot;duplicate block argument name&quot;);
			$$ = NEW_BLOCK_ARG($2);
		    }
		;

opt_f_block_arg	: ',' f_b…
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