parse.y

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

  parse.y -

  $Author$
  $Date$
  created at: Fri May 28 18:02:42 JST 1993

  Copyright (C) 1993-2001 Yukihiro Matsumoto

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

%{

#define YYDEBUG 1
#include "ruby.h"
#include "env.h"
#include "node.h"
#include "st.h"
#include <stdio.h>
#include <errno.h>

#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 is_notop_id(id) ((id)>LAST_TOKEN)
#define is_local_id(id) (is_notop_id(id)&&((id)&ID_SCOPE_MASK)==ID_LOCAL)
#define is_global_id(id) (is_notop_id(id)&&((id)&ID_SCOPE_MASK)==ID_GLOBAL)
#define is_instance_id(id) (is_notop_id(id)&&((id)&ID_SCOPE_MASK)==ID_INSTANCE)
#define is_attrset_id(id) (is_notop_id(id)&&((id)&ID_SCOPE_MASK)==ID_ATTRSET)
#define is_const_id(id) (is_notop_id(id)&&((id)&ID_SCOPE_MASK)==ID_CONST)
#define is_class_id(id) (is_notop_id(id)&&((id)&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 a operator. */
    EXPR_ARG,			/* newline significant, +/- is a operator. */
    EXPR_MID,			/* newline significant, +/- is a 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;

#if SIZEOF_LONG_LONG > 0
typedef unsigned long long stack_type;
#elif SIZEOF___INT64 > 0
typedef unsigned __int64 stack_type;
#else
typedef unsigned long stack_type;
#endif

static int cond_nest = 0;
static stack_type cond_stack = 0;
#define COND_PUSH do {\
    cond_nest++;\
    cond_stack = (cond_stack<<1)|1;\
} while(0)
#define COND_POP do {\
    cond_nest--;\
    cond_stack >>= 1;\
} while (0)
#define COND_P() (cond_nest > 0 && (cond_stack&1))

static stack_type cmdarg_stack = 0;
#define CMDARG_PUSH do {\
    cmdarg_stack = (cmdarg_stack<<1)|1;\
} while(0)
#define CMDARG_POP do {\
    cmdarg_stack >>= 1;\
} while (0)
#define CMDARG_P() (cmdarg_stack && (cmdarg_stack&1))

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

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 *call_op();
static int in_defined = 0;

static NODE *arg_blk_pass();
static NODE *new_call();
static NODE *new_fcall();
static NODE *new_super();

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

static void top_local_init();
static void top_local_setup();
%}

%union {
    NODE *node;
    VALUE val;
    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 <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR
%token <val>  tINTEGER tFLOAT tSTRING tXSTRING tREGEXP
%token <node> tDSTRING tDXSTRING tDREGEXP tNTH_REF tBACK_REF tQWORDS

%type <node> singleton string
%type <val>  literal numeric
%type <node> compstmt stmts stmt expr arg primary command command_call method_call
%type <node> if_tail opt_else case_body cases rescue exc_list exc_var ensure
%type <node> args ret_args when_args call_args paren_args opt_paren_args
%type <node> command_args aref_args opt_block_arg block_arg var_ref
%type <node> mrhs mrhs_basic superclass block_call block_command
%type <node> f_arglist f_args f_optarg f_opt f_block_arg opt_f_block_arg
%type <node> assoc_list assocs assoc undef_list backref
%type <node> block_var opt_block_var brace_block do_block lhs none
%type <node> mlhs mlhs_head mlhs_basic mlhs_entry mlhs_item mlhs_node
%type <id>   fitem variable sym symbol operation operation2 operation3
%type <id>   cname fname op f_rest_arg
%type <num>  f_norm_arg f_arg
%token tUPLUS 		/* unary+ */
%token tUMINUS 		/* unary- */
%token tPOW		/* ** */
%token tCMP  		/* <=> */
%token tEQ  		/* == */
%token tEQQ  		/* === */
%token tNEQ  		/* != */
%token tGEQ  		/* >= */
%token tLEQ  		/* <= */
%token tANDOP tOROP	/* && and || */
%token tMATCH tNMATCH	/* =~ and !~ */
%token tDOT2 tDOT3	/* .. and ... */
%token tAREF tASET	/* [] and []= */
%token tLSHFT tRSHFT	/* << and >> */
%token tCOLON2		/* :: */
%token tCOLON3		/* :: at EXPR_BEG */
%token <id> tOP_ASGN	/* +=, -=  etc. */
%token tASSOC		/* => */
%token tLPAREN		/* ( */
%token tLBRACK		/* [ */
%token tLBRACE		/* { */
%token tSTAR		/* * */
%token tAMPER		/* & */
%token tSYMBEG

/*
 *	precedence table
 */

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

%token LAST_TOKEN

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

stmt		: kALIAS fitem {lex_state = EXPR_FNAME;} fitem
		    {
			if (in_def || in_single)
			    yyerror("alias within method");
		        $$ = NEW_ALIAS($2, $4);
		    }
		| kALIAS tGVAR tGVAR
		    {
			if (in_def || in_single)
			    yyerror("alias within method");
		        $$ = NEW_VALIAS($2, $3);
		    }
		| kALIAS tGVAR tBACK_REF
		    {
			char buf[3];

			if (in_def || in_single)
			    yyerror("alias within method");
			sprintf(buf, "$%c", (int)$3->nd_nth);
		        $$ = NEW_VALIAS($2, rb_intern(buf));
		    }
		| kALIAS tGVAR tNTH_REF
		    {
		        yyerror("can't make alias for the number variables");
		        $$ = 0;
		    }
		| kUNDEF undef_list
		    {
			if (in_def || in_single)
			    yyerror("undef within method");
			$$ = $2;
		    }
		| stmt kIF_MOD expr
		    {
			value_expr($3);
			$$ = NEW_IF(cond($3), $1, 0);
		        fixpos($$, $3);
		    }
		| stmt kUNLESS_MOD expr
		    {
			value_expr($3);
			$$ = NEW_UNLESS(cond($3), $1, 0);
		        fixpos($$, $3);
		    }
		| stmt kWHILE_MOD expr
		    {
			value_expr($3);
			if ($1 && nd_type($1) == NODE_BEGIN) {
			    $$ = NEW_WHILE(cond($3), $1->nd_body, 0);
			}
			else {
			    $$ = NEW_WHILE(cond($3), $1, 1);
			}
		    }
		| stmt kUNTIL_MOD expr
		    {
			value_expr($3);
			if ($1 && nd_type($1) == NODE_BEGIN) {
			    $$ = NEW_UNTIL(cond($3), $1->nd_body, 0);
			}
			else {
			    $$ = NEW_UNTIL(cond($3), $1, 1);
			}
		    }
		| stmt kRESCUE_MOD stmt
		    {
			$$ = NEW_RESCUE($1, NEW_RESBODY(0,$3,0), 0);
		    }
		| klBEGIN
		    {
			if (in_def || in_single) {
			    yyerror("BEGIN in method");
			}
			local_push(0);
		    }
		  '{' compstmt '}'
		    {
			ruby_eval_tree_begin = block_append(ruby_eval_tree_begin,
						            NEW_PREEXE($4));
		        local_pop();
		        $$ = 0;
		    }
		| klEND '{' compstmt '}'
		    {
			if (compile_for_eval && (in_def || in_single)) {
			    yyerror("END in method; use at_exit");
			}

			$$ = NEW_ITER(0, NEW_POSTEXE(), $3);
		    }
		| lhs '=' command_call
		    {
			$$ = node_assign($1, $3);
		    }
		| mlhs '=' command_call
		    {
			value_expr($3);
			$1->nd_value = $3;
			$$ = $1;
		    }
		| lhs '=' mrhs_basic
		    {
			$$ = node_assign($1, $3);
		    }
		| expr
		;

expr		: mlhs '=' mrhs
		    {
			value_expr($3);
			$1->nd_value = $3;
			$$ = $1;
		    }
		| kRETURN ret_args
		    {
			if (!compile_for_eval && !in_def && !in_single)
			    yyerror("return appeared outside of method");
			$$ = NEW_RETURN($2);
		    }
		| command_call
		| expr kAND expr
		    {
			$$ = logop(NODE_AND, $1, $3);
		    }
		| expr kOR expr
		    {
			$$ = logop(NODE_OR, $1, $3);
		    }
		| kNOT expr
		    {
			value_expr($2);
			$$ = NEW_NOT(cond($2));
		    }
		| '!' command_call
		    {
			value_expr($2);
			$$ = NEW_NOT(cond($2));
		    }
		| arg
		;

command_call	: command
		| block_command
		;

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

command		:  operation command_args
		    {
			$$ = new_fcall($1, $2);
		        fixpos($$, $2);
		   }
		| primary '.' operation2 command_args
		    {
			value_expr($1);
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary tCOLON2 operation2 command_args
		    {
			value_expr($1);
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| kSUPER command_args
		    {
			if (!compile_for_eval && !in_def && !in_single)
			    yyerror("super called outside of method");
			$$ = new_super($2);
		        fixpos($$, $2);
		    }
		| kYIELD ret_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
		    {
			$$ = assignable($1, 0);
		    }
		| primary '[' aref_args ']'
		    {
			$$ = aryset($1, $3);
		    }
		| primary '.' tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary tCOLON2 tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary '.' tCONSTANT
		    {
			$$ = attrset($1, $3);
		    }
		| backref
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		;

lhs		: variable
		    {
			$$ = assignable($1, 0);
		    }
		| primary '[' aref_args ']'
		    {
			$$ = aryset($1, $3);
		    }
		| primary '.' tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary tCOLON2 tIDENTIFIER
		    {
			$$ = attrset($1, $3);
		    }
		| primary '.' tCONSTANT
		    {
			$$ = attrset($1, $3);
		    }
		| backref
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		;

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

fname		: tIDENTIFIER
		| tCONSTANT
		| tFID
		| op
		    {
			lex_state = EXPR_END;
			$$ = $1;
		    }
		| reswords
		    {
			lex_state = EXPR_END;
			$$ = $<id>1;
		    }
		;

fitem		: fname
		| symbol
		;

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

op		: '|'		{ $$ = '|'; }
		| '^'		{ $$ = '^'; }
		| '&'		{ $$ = '&'; }
		| tCMP		{ $$ = tCMP; }
		| tEQ		{ $$ = tEQ; }
		| tEQQ		{ $$ = tEQQ; }
		| tMATCH	{ $$ = tMATCH; }
		| '>'		{ $$ = '>'; }
		| tGEQ		{ $$ = tGEQ; }
		| '<'		{ $$ = '<'; }
		| 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 | kIF_MOD | kIN | kMODULE | kNEXT | kNIL | kNOT
		| kOR | kREDO | kRESCUE | kRETRY | kRETURN | kSELF | kSUPER
		| kTHEN | kTRUE | kUNDEF | kUNLESS_MOD | kUNTIL_MOD | kWHEN
		| kWHILE_MOD | kYIELD | kRESCUE_MOD
		;

arg		: lhs '=' arg
		    {
			$$ = node_assign($1, $3);
		    }
		| variable tOP_ASGN {$$ = assignable($1, 0);} arg
		    {
			value_expr($4);
			if ($<node>3) {
			    if ($2 == tOROP) {
				$<node>3->nd_value = $4;
				$$ = NEW_OP_ASGN_OR(gettable($1), $<node>3);
				if (is_instance_id($1)) {
				    $$->nd_aid = $1;
				}
			    }
			    else if ($2 == tANDOP) {
				$<node>3->nd_value = $4;
				$$ = NEW_OP_ASGN_AND(gettable($1), $<node>3);
			    }
			    else {
				$$ = $<node>3;
				$$->nd_value = call_op(gettable($1),$2,1,$4);
			    }
			    fixpos($$, $4);
			}
			else {
			    $$ = 0;
			}
		    }
		| primary '[' aref_args ']' tOP_ASGN arg
		    {
                        NODE *args = NEW_LIST($6);

			value_expr($6);
			$3 = list_append($3, NEW_NIL());
			list_concat(args, $3);
			if ($5 == tOROP) {
			    $5 = 0;
			}
			else if ($5 == tANDOP) {
			    $5 = 1;
			}
			$$ = NEW_OP_ASGN1($1, $5, args);
		        fixpos($$, $1);
		    }
		| primary '.' 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 '.' 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 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);
		    }
		| backref tOP_ASGN arg
		    {
		        rb_backref_error($1);
			$$ = 0;
		    }
		| arg tDOT2 arg
		    {
			value_expr($1);
			value_expr($3);
			$$ = NEW_DOT2($1, $3);
		    }
		| arg tDOT3 arg
		    {
			value_expr($1);
			value_expr($3);
			$$ = NEW_DOT3($1, $3);
		    }
		| arg '+' arg
		    {
			$$ = 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
		    {
			int need_negate = Qfalse;

			if ($1 && nd_type($1) == NODE_LIT) {

			    switch (TYPE($1->nd_lit)) {
			      case T_FIXNUM:
			      case T_FLOAT:
			      case T_BIGNUM:
				if (RTEST(rb_funcall($1->nd_lit,'<',1,INT2FIX(0)))) {
				    $1->nd_lit = rb_funcall($1->nd_lit,rb_intern("-@"),0,0);
				    need_negate = Qtrue;
				}
			      default:
				break;
			    }
			}
			$$ = call_op($1, tPOW, 1, $3);
			if (need_negate) {
			    $$ = call_op($$, tUMINUS, 0, 0);
			}
		    }
		| tUPLUS arg
		    {
			if ($2 && nd_type($2) == NODE_LIT) {
			    $$ = $2;
			}
			else {
			    $$ = call_op($2, tUPLUS, 0, 0);
			}
		    }
		| tUMINUS arg
		    {
			if ($2 && nd_type($2) == NODE_LIT && FIXNUM_P($2->nd_lit)) {
			    long i = FIX2LONG($2->nd_lit);

			    $2->nd_lit = INT2NUM(-i);
			    $$ = $2;
			}
			else {
			    $$ = call_op($2, tUMINUS, 0, 0);
			}
		    }
		| arg '|' arg
		    {
		        $$ = call_op($1, '|', 1, $3);
		    }
		| arg '^' arg
		    {
			$$ = call_op($1, '^', 1, $3);
		    }
		| arg '&' arg
		    {
			$$ = call_op($1, '&', 1, $3);
		    }
		| arg tCMP arg
		    {
			$$ = call_op($1, tCMP, 1, $3);
		    }
		| arg '>' arg
		    {
			$$ = call_op($1, '>', 1, $3);
		    }
		| arg tGEQ arg
		    {
			$$ = call_op($1, tGEQ, 1, $3);
		    }
		| arg '<' arg
		    {
			$$ = call_op($1, '<', 1, $3);
		    }
		| arg tLEQ arg
		    {
			$$ = 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
		    {
			$$ = NEW_NOT(match_gen($1, $3));
		    }
		| '!' arg
		    {
			value_expr($2);
			$$ = 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
		    {
			value_expr($1);
			$$ = NEW_IF(cond($1), $3, $5);
		        fixpos($$, $1);
		    }
		| primary
		    {
			$$ = $1;
		    }
		;

aref_args	: none
		| command_call opt_nl
		    {
			$$ = NEW_LIST($1);
		    }
		| args ',' command_call opt_nl
		    {
			$$ = list_append($1, $3);
		    }
		| 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_RESTARGS($2);
		    }
		;

paren_args	: '(' none ')'
		    {
			$$ = $2;
		    }
		| '(' call_args opt_nl ')'
		    {
			$$ = $2;
		    }
		| '(' block_call opt_nl ')'
		    {
			$$ = NEW_LIST($2);
		    }
		| '(' args ',' block_call opt_nl ')'
		    {
			$$ = list_append($2, $4);
		    }
		;

opt_paren_args	: none
		| paren_args
		;

call_args	: command
		    {
			$$ = NEW_LIST($1);
		    }
		| args ',' command
		    {
			$$ = list_append($1, $3);
		    }
		| args opt_block_arg
		    {
			$$ = arg_blk_pass($1, $2);
		    }
		| args ',' tSTAR arg opt_block_arg
		    {
			value_expr($4);
			$$ = arg_concat($1, $4);
			$$ = arg_blk_pass($$, $5);
		    }
		| assocs opt_block_arg
		    {
			$$ = NEW_LIST(NEW_HASH($1));
			$$ = arg_blk_pass($$, $2);
		    }
		| assocs ',' tSTAR arg opt_block_arg
		    {
			value_expr($4);
			$$ = 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 opt_block_arg
		    {
			value_expr($2);
			$$ = arg_blk_pass(NEW_RESTARGS($2), $3);
		    }
		| block_arg
		;

command_args	: {CMDARG_PUSH;} call_args
		    {
		        CMDARG_POP;
			$$ = $2;
		    }
		;

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

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

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

mrhs		: arg
		    {
			value_expr($1);
			$$ = $1;
		    }
		| mrhs_basic
		;

mrhs_basic	: args ',' arg
		    {
			value_expr($3);
			$$ = list_append($1, $3);
		    }
		| args ',' tSTAR arg
		    {
			value_expr($4);
			$$ = arg_concat($1, $4);
		    }
		| tSTAR arg
		    {
			value_expr($2);
			$$ = $2;
		    }
		;

ret_args	: call_args
		    {
			$$ = $1;
			if ($1) {
			    if (nd_type($1) == NODE_ARRAY &&
				$1->nd_next == 0) {
				$$ = $1->nd_head;
			    }
			    else if (nd_type($1) == NODE_BLOCK_PASS) {
				rb_compile_error("block argument should not be given");
			    }
			}
		    }
		;

primary		: literal
		    {
			$$ = NEW_LIT($1);
		    }
		| string
		| tXSTRING
		    {
			$$ = NEW_XSTR($1);
		    }
		| tQWORDS
		| tDXSTRING
		| tDREGEXP
		| var_ref
		| backref
		| tFID
		    {
			$$ = NEW_VCALL($1);
		    }
		| kBEGIN
		  compstmt
		  rescue
		  opt_else
		  ensure
		  kEND
		    {
			if (!$3 && !$4 && !$5)
			    $$ = NEW_BEGIN($2);
			else {
			    if ($3) $2 = NEW_RESCUE($2, $3, $4);
			    else if ($4) {
				rb_warn("else without rescue is useless");
				$2 = block_append($2, $4);
			    }
			    if ($5) $2 = NEW_ENSURE($2, $5);
			    $$ = $2;
			}
		        fixpos($$, $2);
		    }
		| tLPAREN compstmt ')'
		    {
			$$ = $2;
		    }
		| primary tCOLON2 tCONSTANT
		    {
			value_expr($1);
			$$ = NEW_COLON2($1, $3);
		    }
		| tCOLON3 cname
		    {
			$$ = NEW_COLON3($2);
		    }
		| primary '[' aref_args ']'
		    {
			value_expr($1);
			$$ = NEW_CALL($1, tAREF, $3);
		    }
		| tLBRACK aref_args ']'
		    {
			if ($2 == 0)
			    $$ = NEW_ZARRAY(); /* zero length array*/
			else {
			    $$ = $2;
			}
		    }
		| tLBRACE assoc_list '}'
		    {
			$$ = NEW_HASH($2);
		    }
		| kRETURN '(' ret_args ')'
		    {
			if (!compile_for_eval && !in_def && !in_single)
			    yyerror("return appeared outside of method");
			value_expr($3);
			$$ = NEW_RETURN($3);
		    }
		| kRETURN '(' ')'
		    {
			if (!compile_for_eval && !in_def && !in_single)
			    yyerror("return appeared outside of method");
			$$ = NEW_RETURN(0);
		    }
		| kRETURN
		    {
			if (!compile_for_eval && !in_def && !in_single)
			    yyerror("return appeared outside of method");
			$$ = NEW_RETURN(0);
		    }
		| kYIELD '(' ret_args ')'
		    {
			value_expr($3);
			$$ = NEW_YIELD($3);
		    }
		| kYIELD '(' ')'
		    {
			$$ = NEW_YIELD(0);
		    }
		| kYIELD
		    {
			$$ = NEW_YIELD(0);
		    }
		| kDEFINED opt_nl '(' {in_defined = 1;} expr ')'
		    {
		        in_defined = 0;
			$$ = NEW_DEFINED($5);
		    }
		| operation brace_block
		    {
			$2->nd_iter = NEW_FCALL($1, 0);
			$$ = $2;
		    }
		| method_call
		| method_call brace_block
		    {
			if ($1 && nd_type($1) == NODE_BLOCK_PASS) {
			    rb_compile_error("both block arg and actual block given");
			}
			$2->nd_iter = $1;
			$$ = $2;
		        fixpos($$, $1);
		    }
		| kIF expr then
		  compstmt
		  if_tail
		  kEND
		    {
			value_expr($2);
			$$ = NEW_IF(cond($2), $4, $5);
		        fixpos($$, $2);
		    }
		| kUNLESS expr then
		  compstmt
		  opt_else
		  kEND
		    {
			value_expr($2);
			$$ = NEW_UNLESS(cond($2), $4, $5);
		        fixpos($$, $2);
		    }
		| kWHILE {COND_PUSH;} expr do {COND_POP;}
		  compstmt
		  kEND
		    {
			value_expr($3);
			$$ = NEW_WHILE(cond($3), $6, 1);
		        fixpos($$, $3);
		    }
		| kUNTIL {COND_PUSH;} expr do {COND_POP;} 
		  compstmt
		  kEND
		    {
			value_expr($3);
			$$ = NEW_UNTIL(cond($3), $6, 1);
		        fixpos($$, $3);
		    }
		| kCASE expr opt_terms
		  case_body
		  kEND
		    {
			value_expr($2);
			$$ = NEW_CASE($2, $4);
		        fixpos($$, $2);
		    }
		| kCASE opt_terms case_body kEND
		    {
			$$ = $3;
		    }
		| kFOR block_var kIN {COND_PUSH;} expr do {COND_POP;}
		  compstmt
		  kEND
		    {
			value_expr($5);
			$$ = NEW_FOR($2, $5, $8);
		        fixpos($$, $2);
		    }
		| kCLASS cname superclass
		    {
			if (in_def || in_single)
			    yyerror("class definition in method body");
			class_nest++;
			local_push(0);
		        $<num>$ = ruby_sourceline;
		    }
		  compstmt
		  kEND
		    {
		        $$ = NEW_CLASS($2, $5, $3);
		        nd_set_line($$, $<num>4);
		        local_pop();
			class_nest--;
		    }
		| kCLASS tLSHFT expr
		    {
			$<num>$ = in_def;
		        in_def = 0;
		    }
		  term
		    {
		        $<num>$ = in_single;
		        in_single = 0;
			class_nest++;
			local_push(0);
		    }
		  compstmt
		  kEND
		    {
		        $$ = NEW_SCLASS($3, $7);
		        fixpos($$, $3);
		        local_pop();
			class_nest--;
		        in_def = $<num>4;
		        in_single = $<num>6;
		    }
		| kMODULE cname
		    {
			if (in_def || in_single)
			    yyerror("module definition in method body");
			class_nest++;
			local_push(0);
		        $<num>$ = ruby_sourceline;
		    }
		  compstmt
		  kEND
		    {
		        $$ = NEW_MODULE($2, $4);
		        nd_set_line($$, $<num>3);
		        local_pop();
			class_nest--;
		    }
		| kDEF fname
		    {
			if (in_def || in_single)
			    yyerror("nested method definition");
			$<id>$ = cur_mid;
			cur_mid = $2;
			in_def++;
			local_push(0);
		    }
		  f_arglist
		  compstmt
		  rescue
		  opt_else
		  ensure
		  kEND
		    {
		        if ($6) $5 = NEW_RESCUE($5, $6, $7);
			else if ($7) {
			    rb_warn("else without rescue is useless");
			    $5 = block_append($5, $7);
			}
			if ($8) $5 = NEW_ENSURE($5, $8);

			$$ = NEW_DEFN($2, $4, $5, NOEX_PRIVATE);
			if (is_attrset_id($2)) $$->nd_noex = NOEX_PUBLIC;
		        fixpos($$, $4);
		        local_pop();
			in_def--;
			cur_mid = $<id>3;
		    }
		| kDEF singleton dot_or_colon {lex_state = EXPR_FNAME;} fname
		    {
			value_expr($2);
			in_single++;
			local_push(0);
		        lex_state = EXPR_END; /* force for args */
		    }
		  f_arglist
		  compstmt
		  rescue
		  opt_else
		  ensure
		  kEND
		    {
		        if ($9) $8 = NEW_RESCUE($8, $9, $10);
			else if ($10) {
			    rb_warn("else without rescue is useless");
			    $8 = block_append($8, $10);
			}
			if ($11) $8 = NEW_ENSURE($8, $11);

			$$ = NEW_DEFS($2, $5, $7, $8);
		        fixpos($$, $2);
		        local_pop();
			in_single--;
		    }
		| kBREAK
		    {
			$$ = NEW_BREAK();
		    }
		| kNEXT
		    {
			$$ = NEW_NEXT();
		    }
		| kREDO
		    {
			$$ = NEW_REDO();
		    }
		| kRETRY
		    {
			$$ = NEW_RETRY();
		    }
		;

then		: term
		| kTHEN
		| term kTHEN
		;

do		: term
		| kDO_COND
		;

if_tail		: opt_else
		| kELSIF expr then
		  compstmt
		  if_tail
		    {
			value_expr($2);
			$$ = NEW_IF(cond($2), $4, $5);
		        fixpos($$, $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
		    {
		        $<vars>$ = dyna_push();
		    }
		  opt_block_var
		  compstmt
		  kEND
		    {
			$$ = NEW_ITER($3, 0, $4);
		        fixpos($$, $3?$3:$4);
			dyna_pop($<vars>2);
		    }
		;

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

method_call	: operation paren_args
		    {
			$$ = new_fcall($1, $2);
		        fixpos($$, $2);
		    }
		| primary '.' operation2 opt_paren_args
		    {
			value_expr($1);
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary tCOLON2 operation2 paren_args
		    {
			value_expr($1);
			$$ = new_call($1, $3, $4);
		        fixpos($$, $1);
		    }
		| primary tCOLON2 operation3
		    {
			value_expr($1);
			$$ = new_call($1, $3, 0);
		    }
		| kSUPER paren_args
		    {
			if (!compile_for_eval && !in_def &&
		            !in_single && !in_defined)
			    yyerror("super called outside of method");
			$$ = new_super($2);
		    }
		| kSUPER
		    {
			if (!compile_for_eval && !in_def &&
		            !in_single && !in_defined)
			    yyerror("super called outside of method");
			$$ = NEW_ZSUPER();
		    }
		;

brace_block	: '{'
		    {
		        $<vars>$ = dyna_push();
		    }
		  opt_block_var
		  compstmt '}'
		    {
			$$ = NEW_ITER($3, 0, $4);
		        fixpos($$, $4);
			dyna_pop($<vars>2);
		    }
		| kDO
		    {
		        $<vars>$ = dyna_push();
		    }
		  opt_block_var
		  compstmt kEND
		    {
			$$ = NEW_ITER($3, 0, $4);
		        fixpos($$, $4);
			dyna_pop($<vars>2);
		    }
		;

case_body	: kWHEN when_args then
		  compstmt
		  cases
		    {
			$$ = NEW_WHEN($2, $4, $5);
		    }
		;

when_args	: args
		| args ',' tSTAR arg
		    {
			value_expr($4);
			$$ = list_append($1, NEW_WHEN($4, 0, 0));
		    }
		| tSTAR arg
		    {
			value_expr($2);
			$$ = NEW_LIST(NEW_WHEN($2, 0, 0));
		    }
		;

cases		: opt_else
		| case_body
		;

exc_list	: none
		| args
		;

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

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

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

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

string		: tSTRING
		    {
			$$ = NEW_STR($1);
		    }
		| tDSTRING
		| string tSTRING
		    {
		        if (nd_type($1) == NODE_DSTR) {
			    list_append($1, NEW_STR($2));
			}
			else {
			    rb_str_concat($1->nd_lit, $2);
			}
			$$ = $1;
		    }
		| string tDSTRING
		    {
		        if (nd_type($1) == NODE_STR) {
			    $$ = NEW_DSTR($1->nd_lit);
			}
			else {
			    $$ = $1;
			}
			$2->nd_head = NEW_STR($2->nd_lit);
			nd_set_type($2, NODE_ARRAY);
			list_concat($$, $2);
		    }
		;

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

sym		: fname
		| tIVAR
		| tGVAR
		| tCVAR
		;

numeric		: tINTEGER
		| tFLOAT
		;

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);
		    }
		;

backref		: tNTH_REF
		| tBACK_REF
		;

superclass	: term
		    {
			$$ = 0;
		    }
		| '<'
		    {
			lex_state = EXPR_BEG;
		    }
		  expr term
		    {
			$$ = $3;
		    }
		| error term {yyerrok; $$ = 0;}
		;

f_arglist	: '(' f_args opt_nl ')'
		    {
			$$ = $2;
			lex_state = EXPR_BEG;
		    }
		| f_args term
		    {
			$$ = $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, -1), $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, -1), $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, -1), $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, -1), $1);
		    }
		| /* none */
		    {
			$$ = NEW_ARGS(0, 0, -1);
		    }
		;

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

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

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

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

f_rest_arg	: tSTAR tIDENTIFIER
		    {
			if (!is_local_id($2))
			    yyerror("rest argument must be local variable");
			else if (local_id($2))
			    yyerror("duplicate rest argument name");
			$$ = local_cnt($2);
		    }
		| tSTAR
		    {
			$$ = -2;
		    }
		;

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

opt_f_block_arg	: ',' f_block_arg
		    {
			$$ = $2;
		    }
		| none
		;

singleton	: var_ref
		    {
			if (nd_type($1) == NODE_SELF) {
			    $$ = NEW_SELF();
			}
			else {
			    $$ = $1;
			}
		    }
		| '(' {lex_state = EXPR_BEG;} expr opt_nl ')'
		    {
					if ($3 == 0) {
			    yyerror("can't define single method for ().");
			}
			else {
			    switch (nd_type($3)) {
			      case NODE_STR:
			      case NODE_DSTR:
			      case NODE_XSTR:
			      case NODE_DXSTR:
			      case NODE_DREGX:
			      case NODE_LIT:
			      case NODE_ARRAY:
			      case NODE_ZARRAY:
				yyerror("can't define single method for literals");
			      default:
				value_expr($3);
				break;
			    }
			}
			$$ = $3;
		    }
		;

assoc_list	: none
		| assocs trailer
		    {
			$$ = $1;
		    }
		| args trailer
		    {
			if ($1->nd_alen%2 != 0) {
			    yyerror("odd number list for Hash");
			}
			$$ = $1;
		    }
		;

assocs		: assoc
		| assocs ',' assoc
		    {
			$$ = list_concat($1, $3);
		    }
		;

assoc		: arg tASSOC arg
		    {
			$$ = list_append(NEW_LIST($1), $3);
		    }
		;

operation	: tIDENTIFIER
		| tCONSTANT
		| tFID
		;

operation2	: tIDENTIFIER
		| tCONSTANT
		| tFID
		| op
		;

operation3	: tIDENTIFIER
		| tFID
		| op
		;

dot_or_colon	: '.'
		| tCOLON2
		;

opt_terms	: /* none */
		| terms
		;

opt_nl		: /* none */
		| '\n'
		;

trailer		: /* none */
		| '\n'
		| ','
		;

term		: ';' {yyerrok;}
		| '\n'
		;

terms		: term
		| terms ';' {yyerrok;}
		;

none		: /* none */
		    {
			$$ = 0;
		    }
		;
%%
#include <ctype.h>
#include <sys/types.h>
#include "regex.h"
#include "util.h"

/* We remove any previous definition of `SIGN_EXTEND_CHAR',
   since ours (we hope) works properly with all combinations of
   machines, compilers, `char' and `unsigned char' argument types.
   (Per Bothner suggested the basic approach.)  */
#undef SIGN_EXTEND_CHAR
#if __STDC__
# define SIGN_EXTEND_CHAR(c) ((signed char)(c))
#else  /* not __STDC__ */
/* As in Harbison and Steele.  */
# define SIGN_EXTEND_CHAR(c) ((((unsigned char)(c)) ^ 128) - 128)
#endif
#define is_identchar(c) (SIGN_EXTEND_CHAR(c)!=-1&&(ISALNUM(c) || (c) == '_' || ismbchar(c)))

static char *tokenbuf = NULL;
static int   tokidx, toksiz = 0;

static NODE *str_extend _((NODE*,int,int));

#define LEAVE_BS 1

static VALUE (*lex_gets)();	/* gets function */
static VALUE lex_input;		/* non-nil if File */
static VALUE lex_lastline;	/* gc protect */
static char *lex_pbeg;
static char *lex_p;
static char *lex_pend;

static int
yyerror(msg)
    char *msg;
{
    char *p, *pe, *buf;
    int len, i;

    rb_compile_error("%s", msg);
    p = lex_p;
    while (lex_pbeg <= p) {
	if (*p == '\n') break;
	p--;
    }
    p++;

    pe = lex_p;
    while (pe < lex_pend) {
	if (*pe == '\n') break;
	pe++;
    }

    len = pe - p;
    if (len > 4) {
	buf = ALLOCA_N(char, len+2);
	MEMCPY(buf, p, char, len);
	buf[len] = '\0';
	rb_compile_error_append("%s", buf);

	i = lex_p - p;
	p = buf; pe = p + len;

	while (p < pe) {
	    if (*p != '\t') *p = ' ';
	    p++;
	}
	buf[i] = '^';
	buf[i+1] = '\0';
	rb_compile_error_append("%s", buf);
    }

    return 0;
}

static int heredoc_end;

int ruby_in_compile = 0;
int ruby__end__seen;

static VALUE ruby_debug_lines;

static NODE*
yycompile(f, line)
    char *f;
    int line;
{
    int n;
    NODE *node = 0;

    if (!compile_for_eval && rb_safe_level() == 0 &&
	rb_const_defined(rb_cObject, rb_intern("SCRIPT_LINES__"))) {
	VALUE hash, fname;

	hash = rb_const_get(rb_cObject, rb_intern("SCRIPT_LINES__"));
	if (TYPE(hash) == T_HASH) {
	    fname = rb_str_new2(f);
	    ruby_debug_lines = rb_hash_aref(hash, fname);
	    if (NIL_P(ruby_debug_lines)) {
		ruby_debug_lines = rb_ary_new();
		rb_hash_aset(hash, fname, ruby_debug_lines);
	    }
	}
	if (line > 1) {
	    VALUE str = rb_str_new(0,0);
	    while (line > 1) {
		rb_ary_push(ruby_debug_lines, str);
		line--;
	    }
	}
    }

    ruby__end__seen = 0;
    ruby_eval_tree = 0;
    heredoc_end = 0;
    ruby_sourcefile = rb_source_filename(f);
    ruby_in_compile = 1;
    n = yyparse();
    ruby_debug_lines = 0;
    compile_for_eval = 0;
    ruby_in_compile = 0;
    cond_nest = 0;
    cond_stack = 0;
    cmdarg_stack = 0;
    class_nest = 0;
    in_single = 0;
    in_def = 0;
    cur_mid = 0;

    if (n == 0) node = ruby_eval_tree;
    return node;
}

static int lex_gets_ptr;

static VALUE
lex_get_str(s)
    VALUE s;
{
    char *beg, *end, *pend;

    beg = RSTRING(s)->ptr;
    if (lex_gets_ptr) {
	if (RSTRING(s)->len == lex_gets_ptr) return Qnil;
	beg += lex_gets_ptr;
    }
    pend = RSTRING(s)->ptr + RSTRING(s)->len;
    end = beg;
    while (end < pend) {
	if (*end++ == '\n') break;
    }
    lex_gets_ptr = end - RSTRING(s)->ptr;
    return rb_str_new(beg, end - beg);
}

static VALUE
lex_getline()
{
    VALUE line = (*lex_gets)(lex_input);
    if (ruby_debug_lines && !NIL_P(line)) {
	rb_ary_push(ruby_debug_lines, line);
    }
    return line;
}

NODE*
rb_compile_string(f, s, line)
    const char *f;
    VALUE s;
    int line;
{
    lex_gets = lex_get_str;
    lex_gets_ptr = 0;
    lex_input = s;
    lex_pbeg = lex_p = lex_pend = 0;
    ruby_sourceline = line - 1;
    compile_for_eval = ruby_in_eval;

    return yycompile(f, line);
}

NODE*
rb_compile_cstr(f, s, len, line)
    const char *f, *s;
    int len, line;
{
    return rb_compile_string(f, rb_str_new(s, len), line);
}

NODE*
rb_compile_file(f, file, start)
    const char *f;
    VALUE file;
    int start;
{
    lex_gets = rb_io_gets;
    lex_input = file;
    lex_pbeg = lex_p = lex_pend = 0;
    ruby_sourceline = start - 1;

    return yycompile(f, start);
}

static inline int
nextc()
{
    int c;

    if (lex_p == lex_pend) {
	if (lex_input) {
	    VALUE v = lex_getline();

	    if (NIL_P(v)) return -1;
	    if (heredoc_end > 0) {
		ruby_sourceline = heredoc_end;
		heredoc_end = 0;
	    }
	    ruby_sourceline++;
	    lex_pbeg = lex_p = RSTRING(v)->ptr;
	    lex_pend = lex_p + RSTRING(v)->len;
	    if (strncmp(lex_pbeg, "__END__", 7) == 0 &&
		(RSTRING(v)->len == 7 || lex_pbeg[7] == '\n' || lex_pbeg[7] == '\r')) {
		ruby__end__seen = 1;
		lex_lastline = 0;
		return -1;
	    }
	    lex_lastline = v;
	}
	else {
	    lex_lastline = 0;
	    return -1;
	}
    }
    c = (unsigned char)*lex_p++;
    if (c == '\r' && lex_p <= lex_pend && *lex_p == '\n') {
	lex_p++;
	c = '\n';
    }

    return c;
}

static void
pushback(c)
    int c;
{
    if (c == -1) return;
    lex_p--;
}

#define peek(c) (lex_p != lex_pend && (c) == *lex_p)

#define tokfix() (tokenbuf[tokidx]='\0')
#define tok() tokenbuf
#define toklen() tokidx
#define toklast() (tokidx>0?tokenbuf[tokidx-1]:0)

static char*
newtok()
{
    tokidx = 0;
    if (!tokenbuf) {
	toksiz = 60;
	tokenbuf = ALLOC_N(char, 60);
    }
    if (toksiz > 4096) {
	toksiz = 60;
	REALLOC_N(tokenbuf, char, 60);
    }
    return tokenbuf;
}

static void
tokadd(c)
    char c;
{
    tokenbuf[tokidx++] = c;
    if (tokidx >= toksiz) {
	toksiz *= 2;
	REALLOC_N(tokenbuf, char, toksiz);
    }
}

static int
read_escape()
{
    int c;

    switch (c = nextc()) {
      case '\\':	/* Backslash */
	return c;

      case 'n':	/* newline */
	return '\n';

      case 't':	/* horizontal tab */
	return '\t';

      case 'r':	/* carriage-return */
	return '\r';

      case 'f':	/* form-feed */
	return '\f';

      case 'v':	/* vertical tab */
	return '\13';

      case 'a':	/* alarm(bell) */
	return '\007';

      case 'e':	/* escape */
	return 033;

      case '0': case '1': case '2': case '3': /* octal constant */
      case '4': case '5': case '6': case '7':
	{
	    char buf[3];
	    int i;

	    pushback(c);
	    for (i=0; i<3; i++) {
		c = nextc();
		if (c == -1) goto eof;
		if (c < '0' || '7' < c) {
		    pushback(c);
		    break;
		}
		buf[i] = c;
	    }
	    c = scan_oct(buf, i, &i);
	}
	return c;

      case 'x':	/* hex constant */
	{
	    int numlen;

	    c = scan_hex(lex_p, 2, &numlen);
	    if (numlen == 0) {
		yyerror("Invalid escape character syntax");
		return 0;
	    }
	    lex_p += numlen;
	}
	return c;

      case 'b':	/* backspace */
	return '\010';

      case 's':	/* space */
	return ' ';

      case 'M':
	if ((c = nextc()) != '-') {
	    yyerror("Invalid escape character syntax");
	    pushback(c);
	    return '\0';
	}
	if ((c = nextc()) == '\\') {
	    return read_escape() | 0x80;
	}
	else if (c == -1) goto eof;
	else {
	    return ((c & 0xff) | 0x80);
	}

      case 'C':
	if ((c = nextc()) != '-') {
	    yyerror("Invalid escape character syntax");
	    pushback(c);
	    return '\0';
	}
      case 'c':
	if ((c = nextc())== '\\') {
	    c = read_escape();
	}
	else if (c == '?')
	    return 0177;
	else if (c == -1) goto eof;
	return c & 0x9f;

      eof:
      case -1:
        yyerror("Invalid escape character syntax");
	return '\0';

      default:
	return c;
    }
}

static int
tokadd_escape(term)
    int term;
{
    int c;

    switch (c = nextc()) {
      case '\n':
	return 0;		/* just ignore */

      case '0': case '1': case '2': case '3': /* octal constant */
      case '4': case '5': case '6': case '7':
	{
	    int i;

	    tokadd('\\');
	    tokadd(c);
	    for (i=0; i<2; i++) {
		c = nextc();
		if (c == -1) goto eof;
		if (c < '0' || '7' < c) {
		    pushback(c);
		    break;
		}
		tokadd(c);
	    }
	}
	return 0;

      case 'x':	/* hex constant */
	{
	    int numlen;

	    tokadd('\\');
	    tokadd(c);
	    scan_hex(lex_p, 2, &numlen);
	    if (numlen == 0) {
		yyerror("Invalid escape character syntax");
		return -1;
	    }
	    while (numlen--)
		tokadd(nextc());
	}
	return 0;

      case 'M':
	if ((c = nextc()) != '-') {
	    yyerror("Invalid escape character syntax");
	    pushback(c);
	    return 0;
	}
	tokadd('\\'); tokadd('M'); tokadd('-');
	goto escaped;

      case 'C':
	if ((c = nextc()) != '-') {
	    yyerror("Invalid escape character syntax");
	    pushback(c);
	    return 0;
	}
	tokadd('\\'); tokadd('C'); tokadd('-');
	goto escaped;

      case 'c':
	tokadd('\\'); tokadd('c');
      escaped:
	if ((c = nextc()) == '\\') {
	    return tokadd_escape(term);
	}
	else if (c == -1) goto eof;
	tokadd(c);
	return 0;

      eof:
      case -1:
        yyerror("Invalid escape character syntax");
	return -1;

      default:
	if (c != term)
	    tokadd('\\');
	tokadd(c);
    }
    return 0;
}

static int
parse_regx(term, paren)
    int term, paren;
{
    register int c;
    char kcode = 0;
    int once = 0;
    int nest = 0;
    int options = 0;
    int re_start = ruby_sourceline;
    NODE *list = 0;

    newtok();
    while ((c = nextc()) != -1) {
	if (c == term && nest == 0) {
	    goto regx_end;
	}

	switch (c) {
	  case '#':
	    list = str_extend(list, term, paren);
	    if (list == (NODE*)-1) goto unterminated;
	    continue;

	  case '\\':
	    if (tokadd_escape(term) < 0)
		return 0;
	    continue;

	  case -1:
	    goto unterminated;

	  default:
	    if (paren)  {
	      if (c == paren) nest++;
	      if (c == term) nest--;
	    }
	    if (ismbchar(c)) {
		int i, len = mbclen(c)-1;

		for (i = 0; i < len; i++) {
		    tokadd(c);
		    c = nextc();
		}
	    }
	    break;

	  regx_end:
	    for (;;) {
		switch (c = nextc()) {
		  case 'i':
		    options |= RE_OPTION_IGNORECASE;
		    break;
		  case 'x':
		    options |= RE_OPTION_EXTENDED;
		    break;
		  case 'p':	/* /p is obsolete */
		    rb_warn("/p option is obsolete; use /m\n\tnote: /m does not change ^, $ behavior");
		    options |= RE_OPTION_POSIXLINE;
		    break;
		  case 'm':
		    options |= RE_OPTION_MULTILINE;
		    break;
		  case 'o':
		    once = 1;
		    break;
		  case 'n':
		    kcode = 16;
		    break;
		  case 'e':
		    kcode = 32;
		    break;
		  case 's':
		    kcode = 48;
		    break;
		  case 'u':
		    kcode = 64;
		    break;
		  default:
		    pushback(c);
		    goto end_options;
		}
	    }

	  end_options:
	    tokfix();
	    lex_state = EXPR_END;
	    if (list) {
		nd_set_line(list, re_start);
		if (toklen() > 0) {
		    VALUE ss = rb_str_new(tok(), toklen());
		    list_append(list, NEW_STR(ss));
		}
		nd_set_type(list, once?NODE_DREGX_ONCE:NODE_DREGX);
		list->nd_cflag = options | kcode;
		yylval.node = list;
		return tDREGEXP;
	    }
	    else {
		yylval.val = rb_reg_new(tok(), toklen(), options | kcode);
		return tREGEXP;
	    }
	}
	tokadd(c);
    }
  unterminated:
    ruby_sourceline = re_start;
    rb_compile_error("unterminated regexp meets end of file");
    return 0;
}

static int parse_qstring _((int,int));

static int
parse_string(func, term, paren)
    int func, term, paren;
{
    int c;
    NODE *list = 0;
    int strstart;
    int nest = 0;

    if (func == '\'') {
	return parse_qstring(term, paren);
    }
    if (func == 0) {		/* read 1 line for heredoc */
				/* -1 for chomp */
	yylval.val = rb_str_new(lex_pbeg, lex_pend - lex_pbeg - 1);
	lex_p = lex_pend;
	return tSTRING;
    }
    strstart = ruby_sourceline;
    newtok();
    while ((c = nextc()) != term || nest > 0) {
	if (c == -1) {
	  unterm_str:
	    ruby_sourceline = strstart;
	    rb_compile_error("unterminated string meets end of file");
	    return 0;
	}
	if (paren) {
	    if (c == paren) nest++;
	    if (c == term && nest-- == 0) break;
	}
	if (ismbchar(c)) {
	    int i, len = mbclen(c)-1;

	    for (i = 0; i < len; i++) {
		tokadd(c);
		c = nextc();
	    }
	}
	else if (c == '#') {
	    list = str_extend(list, term, paren);
	    if (list == (NODE*)-1) goto unterm_str;
	    continue;
	}
	else if (c == '\\') {
	    c = nextc();
	    if (c == '\n')
		continue;
	    if (c == term) {
		tokadd(c);
	    }
	    else {
                pushback(c);
                if (func != '"') tokadd('\\');
                tokadd(read_escape());
  	    }
	    continue;
	}
	tokadd(c);
    }

    tokfix();
    lex_state = EXPR_END;

    if (list) {
	nd_set_line(list, strstart);
	if (toklen() > 0) {
	    VALUE ss = rb_str_new(tok(), toklen());
	    list_append(list, NEW_STR(ss));
	}
	yylval.node = list;
	if (func == '`') {
	    nd_set_type(list, NODE_DXSTR);
	    return tDXSTRING;
	}
	else {
	    return tDSTRING;
	}
    }
    else {
	yylval.val = rb_str_new(tok(), toklen());
	return (func == '`') ? tXSTRING : tSTRING;
    }
}

static int
parse_qstring(term, paren)
    int term, paren;
{
    int strstart;
    int c;
    int nest = 0;

    strstart = ruby_sourceline;
    newtok();
    while ((c = nextc()) != term || nest > 0) {
	if (c == -1) {
	    ruby_sourceline = strstart;
	    rb_compile_error("unterminated string meets end of file");
	    return 0;
	}
	if (paren) {
	    if (c == paren) nest++;
	    if (c == term && nest-- == 0) break;
	}
	if (ismbchar(c)) {
	    int i, len = mbclen(c)-1;

	    for (i = 0; i < len; i++) {
		tokadd(c);
		c = nextc();
	    }
	}
	else if (c == '\\') {
	    c = nextc();
	    switch (c) {
	      case '\n':
		continue;

	      case '\\':
		c = '\\';
		break;

	      default:
		/* fall through */
		if (c == term || (paren && c == paren)) {
		    tokadd(c);
		    continue;
		}
		tokadd('\\');
	    }
	}
	tokadd(c);
    }

    tokfix();
    yylval.val = rb_str_new(tok(), toklen());
    lex_state = EXPR_END;
    return tSTRING;
}

static int
parse_quotedwords(term, paren)
    int term, paren;
{
    NODE *qwords = 0;
    int strstart;
    int c;
    int nest = 0;

    strstart = ruby_sourceline;
    newtok();

    while (c = nextc(),ISSPACE(c))
	;		/* skip preceding spaces */
    pushback(c);
    while ((c = nextc()) != term || nest > 0) {
	if (c == -1) {
	    ruby_sourceline = strstart;
	    rb_compile_error("unterminated string meets end of file");
	    return 0;
	}
	if (paren) {
	    if (c == paren) nest++;
	    if (c == term && nest-- == 0) break;
	}
	if (ismbchar(c)) {
	    int i, len = mbclen(c)-1;

	    for (i = 0; i < len; i++) {
		tokadd(c);
		c = nextc();
	    }
	}
	else if (c == '\\') {
	    c = nextc();
	    switch (c) {
	      case '\n':
		continue;
	      case '\\':
		c = '\\';
		break;
	      default:
		if (c == term || (paren && c == paren)) {
		    tokadd(c);
		    continue;
		}
		if (!ISSPACE(c))
		    tokadd('\\');
		break;
	    }
	}
	else if (ISSPACE(c)) {
	    NODE *str;

	    tokfix();
	    str = NEW_STR(rb_str_new(tok(), toklen()));
	    newtok();
	    if (!qwords) qwords = NEW_LIST(str);
	    else list_append(qwords, str);
	    while (c = nextc(),ISSPACE(c))
		;		/* skip continuous spaces */
	    pushback(c);
	    continue;
	}
	tokadd(c);
    }

    tokfix();
    if (toklen() > 0) {
	NODE *str;

	str = NEW_STR(rb_str_new(tok(), toklen()));
	if (!qwords) qwords = NEW_LIST(str);
	else list_append(qwords, str);
    }
    if (!qwords) qwords = NEW_ZARRAY();
    yylval.node = qwords;
    lex_state = EXPR_END;
    return tQWORDS;
}

static int
here_document(term, indent)
    char term;
    int indent;
{
    int c;
    char *eos, *p;
    int len;
    VALUE str;
    volatile VALUE line = 0;
    VALUE lastline_save;
    int offset_save;
    NODE *list = 0;
    int linesave = ruby_sourceline;
    int firstline;

    if (heredoc_end > 0) ruby_sourceline = heredoc_end;
    firstline = ruby_sourceline;

    newtok();
    switch (term) {
      case '\'':
      case '"':
      case '`':
	while ((c = nextc()) != term) {
	    switch (c) {
	      case -1:
		rb_compile_error("unterminated here document identifier meets end of file");
		return 0;
	      case '\n':
		rb_compile_error("unterminated here document identifier meets end of line");
		return 0;
	    }
	    tokadd(c);
	}
	if (term == '\'') term = 0;
	break;

      default:
	c = term;
	term = '"';
	if (!is_identchar(c)) {
	    rb_warn("use of bare << to mean <<\"\" is deprecated");
	    break;
	}
	while (is_identchar(c)) {
	    tokadd(c);
	    c = nextc();
	}
	pushback(c);
	break;
    }
    tokfix();
    lastline_save = lex_lastline;
    offset_save = lex_p - lex_pbeg;
    eos = strdup(tok());
    len = strlen(eos);

    str = rb_str_new(0,0);
    for (;;) {
	lex_lastline = line = lex_getline();
	if (NIL_P(line)) {
	  error:
	    ruby_sourceline = linesave;
	    rb_compile_error("can't find string \"%s\" anywhere before EOF", eos);
	    free(eos);
	    return 0;
	}
	ruby_sourceline++;
	p = RSTRING(line)->ptr;
	if (indent) {
	    while (*p && (*p == ' ' || *p == '\t')) {
		p++;
	    }
	}
	if (strncmp(eos, p, len) == 0) {
	    if (p[len] == '\n' || p[len] == '\r')
		break;
	    if (len == RSTRING(line)->len)
		break;
	}

	lex_pbeg = lex_p = RSTRING(line)->ptr;
	lex_pend = lex_p + RSTRING(line)->len;
#if 0
	if (indent) {
	    while (*lex_p && *lex_p == '\t') {
		lex_p++;
	    }
	}
#endif
      retry:
	switch (parse_string(term, '\n', 0)) {
	  case tSTRING:
	  case tXSTRING:
	    rb_str_cat2(yylval.val, "\n");
	    if (!list) {
	        rb_str_append(str, yylval.val);
	    }
	    else {
		list_append(list, NEW_STR(yylval.val));
	    }
	    break;
	  case tDSTRING:
	    if (!list) list = NEW_DSTR(str);
	    /* fall through */
	  case tDXSTRING:
	    if (!list) list = NEW_DXSTR(str);

	    list_append(yylval.node, NEW_STR(rb_str_new2("\n")));
	    nd_set_type(yylval.node, NODE_STR);
	    yylval.node = NEW_LIST(yylval.node);
	    yylval.node->nd_next = yylval.node->nd_head->nd_next;
	    list_concat(list, yylval.node);
	    break;

	  case 0:
	    goto error;
	}
	if (lex_p != lex_pend) {
	    goto retry;
	}
    }
    free(eos);
    lex_lastline = lastline_save;
    lex_pbeg = RSTRING(lex_lastline)->ptr;
    lex_pend = lex_pbeg + RSTRING(lex_lastline)->len;
    lex_p = lex_pbeg + offset_save;

    lex_state = EXPR_END;
    heredoc_end = ruby_sourceline;
    ruby_sourceline = linesave;

    if (list) {
	nd_set_line(list, firstline+1);
	yylval.node = list;
    }
    switch (term) {
      case '\0':
      case '\'':
      case '"':
	if (list) return tDSTRING;
	yylval.val = str;
	return tSTRING;
      case '`':
	if (list) return tDXSTRING;
	yylval.val = str;
	return tXSTRING;
    }
    return 0;
}

#include "lex.c"

static void
arg_ambiguous()
{
    rb_warning("ambiguous first argument; make sure");
}

static int
yylex()
{
    register int c;
    int space_seen = 0;
    struct kwtable *kw;

  retry:
    switch (c = nextc()) {
      case '\0':		/* NUL */
      case '\004':		/* ^D */
      case '\032':		/* ^Z */
      case -1:			/* end of script. */
	return 0;

	/* white spaces */
      case ' ': case '\t': case '\f': case '\r':
      case '\13': /* '\v' */
	space_seen++;
	goto retry;

      case '#':		/* it's a comment */
	while ((c = nextc()) != '\n') {
	    if (c == -1)
		return 0;
	}
	/* fall through */
      case '\n':
	switch (lex_state) {
	  case EXPR_BEG:
	  case EXPR_FNAME:
	  case EXPR_DOT:
	  case EXPR_CLASS:
	    goto retry;
	  default:
	    break;
	}
	lex_state = EXPR_BEG;
	return '\n';

      case '*':
	if ((c = nextc()) == '*') {
	    if ((c = nextc()) == '=') {
		yylval.id = tPOW;
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    c = tPOW;
	}
	else {
	    if (c == '=') {
		yylval.id = '*';
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    if (lex_state == EXPR_ARG && space_seen && !ISSPACE(c)){
		rb_warning("`*' interpreted as argument prefix");
		c = tSTAR;
	    }
	    else if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
		c = tSTAR;
	    }
	    else {
		c = '*';
	    }
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	return c;

      case '!':
	lex_state = EXPR_BEG;
	if ((c = nextc()) == '=') {
	    return tNEQ;
	}
	if (c == '~') {
	    return tNMATCH;
	}
	pushback(c);
	return '!';

      case '=':
	if (lex_p == lex_pbeg + 1) {
	    /* skip embedded rd document */
	    if (strncmp(lex_p, "begin", 5) == 0 && ISSPACE(lex_p[5])) {
		for (;;) {
		    lex_p = lex_pend;
		    c = nextc();
		    if (c == -1) {
			rb_compile_error("embedded document meets end of file");
			return 0;
		    }
		    if (c != '=') continue;
		    if (strncmp(lex_p, "end", 3) == 0 &&
			(lex_p + 3 == lex_pend || ISSPACE(lex_p[3]))) {
			break;
		    }
		}
		lex_p = lex_pend;
		goto retry;
	    }
	}

	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	if ((c = nextc()) == '=') {
	    if ((c = nextc()) == '=') {
		return tEQQ;
	    }
	    pushback(c);
	    return tEQ;
	}
	if (c == '~') {
	    return tMATCH;
	}
	else if (c == '>') {
	    return tASSOC;
	}
	pushback(c);
	return '=';

      case '<':
	c = nextc();
	if (c == '<' &&
	    lex_state != EXPR_END && lex_state != EXPR_CLASS && lex_state != EXPR_DOT &&
	    (lex_state != EXPR_ARG || space_seen)) {
 	    int c2 = nextc();
	    int indent = 0;
	    if (c2 == '-') {
		indent = 1;
		c2 = nextc();
	    }
	    if (!ISSPACE(c2) && (strchr("\"'`", c2) || is_identchar(c2))) {
		return here_document(c2, indent);
	    }
	    pushback(c2);
	    if (indent) {
		pushback('-');
	    }
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	if (c == '=') {
	    if ((c = nextc()) == '>') {
		return tCMP;
	    }
	    pushback(c);
	    return tLEQ;
	}
	if (c == '<') {
	    if ((c = nextc()) == '=') {
		yylval.id = tLSHFT;
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    return tLSHFT;
	}
	pushback(c);
	return '<';

      case '>':
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	if ((c = nextc()) == '=') {
	    return tGEQ;
	}
	if (c == '>') {
	    if ((c = nextc()) == '=') {
		yylval.id = tRSHFT;
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    return tRSHFT;
	}
	pushback(c);
	return '>';

      case '"':
	return parse_string(c,c,0);
      case '`':
	if (lex_state == EXPR_FNAME) {
	    lex_state = EXPR_END;
	    return c;
	}
	if (lex_state == EXPR_DOT) {
	    lex_state = EXPR_ARG;
	    return c;
	}
	return parse_string(c,c,0);

      case '\'':
	return parse_qstring(c,0);

      case '?':
	if (lex_state == EXPR_END) {
	    lex_state = EXPR_BEG;
	    return '?';
	}
	c = nextc();
	if (c == -1) {
	    return '?';
	}
	if (ISSPACE(c)){
	    if (lex_state != EXPR_ARG){
		int c2 = 0;
		switch (c) {
		  case ' ':
		    c2 = 's';
		    break;
		  case '\n':
		    c2 = 'n';
		    break;
		  case '\t':
		    c2 = 't';
		    break;
		  case '\v':
		    c2 = 'v';
		    break;
		}
		if (c2) {
		    rb_warn("invalid character syntax; use ?\\%c", c);
		}
	    }
	    else {
		pushback(c);
		lex_state = EXPR_BEG;
		return '?';
	    }
	}
	if (c == '\\') {
	    c = read_escape();
	}
	c &= 0xff;
	yylval.val = INT2FIX(c);
	lex_state = EXPR_END;
	return tINTEGER;

      case '&':
	if ((c = nextc()) == '&') {
	    lex_state = EXPR_BEG;
	    if ((c = nextc()) == '=') {
		yylval.id = tANDOP;
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    return tANDOP;
	}
	else if (c == '=') {
	    yylval.id = '&';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	pushback(c);
	if (lex_state == EXPR_ARG && space_seen && !ISSPACE(c)){
	    rb_warning("`&' interpreted as argument prefix");
	    c = tAMPER;
	}
	else if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
	    c = tAMPER;
	}
	else {
	    c = '&';
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG;
	}
	return c;

      case '|':
	if ((c = nextc()) == '|') {
	    lex_state = EXPR_BEG;
	    if ((c = nextc()) == '=') {
		yylval.id = tOROP;
		lex_state = EXPR_BEG;
		return tOP_ASGN;
	    }
	    pushback(c);
	    return tOROP;
	}
	if (c == '=') {
	    yylval.id = '|';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	if (lex_state == EXPR_FNAME || lex_state == EXPR_DOT) {
	    lex_state = EXPR_ARG;
	}
	else {
	    lex_state = EXPR_BEG;
	}
	pushback(c);
	return '|';

      case '+':
	c = nextc();
	if (lex_state == EXPR_FNAME || lex_state == EXPR_DOT) {
	    lex_state = EXPR_ARG;
	    if (c == '@') {
		return tUPLUS;
	    }
	    pushback(c);
	    return '+';
	}
	if (c == '=') {
	    yylval.id = '+';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	if (lex_state == EXPR_BEG || lex_state == EXPR_MID ||
	    (lex_state == EXPR_ARG && space_seen && !ISSPACE(c))) {
	    if (lex_state == EXPR_ARG) arg_ambiguous();
	    lex_state = EXPR_BEG;
	    pushback(c);
	    if (ISDIGIT(c)) {
		c = '+';
		goto start_num;
	    }
	    return tUPLUS;
	}
	lex_state = EXPR_BEG;
	pushback(c);
	return '+';

      case '-':
	c = nextc();
	if (lex_state == EXPR_FNAME || lex_state == EXPR_DOT) {
	    lex_state = EXPR_ARG;
	    if (c == '@') {
		return tUMINUS;
	    }
	    pushback(c);
	    return '-';
	}
	if (c == '=') {
	    yylval.id = '-';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	if (lex_state == EXPR_BEG || lex_state == EXPR_MID ||
	    (lex_state == EXPR_ARG && space_seen && !ISSPACE(c))) {
	    if (lex_state == EXPR_ARG) arg_ambiguous();
	    lex_state = EXPR_BEG;
	    pushback(c);
	    if (ISDIGIT(c)) {
		c = '-';
		goto start_num;
	    }
	    return tUMINUS;
	}
	lex_state = EXPR_BEG;
	pushback(c);
	return '-';

      case '.':
	lex_state = EXPR_BEG;
	if ((c = nextc()) == '.') {
	    if ((c = nextc()) == '.') {
		return tDOT3;
	    }
	    pushback(c);
	    return tDOT2;
	}
	pushback(c);
	if (!ISDIGIT(c)) {
	    lex_state = EXPR_DOT;
	    return '.';
	}
	c = '.';
	/* fall through */

      start_num:
      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
	{
	    int is_float, seen_point, seen_e, nondigit;

	    is_float = seen_point = seen_e = nondigit = 0;
	    lex_state = EXPR_END;
	    newtok();
	    if (c == '-' || c == '+') {
		tokadd(c);
		c = nextc();
	    }
	    if (c == '0') {
		int start = toklen();
		c = nextc();
		if (c == 'x' || c == 'X') {
		    /* hexadecimal */
		    c = nextc();
		    if (ISXDIGIT(c)) {
			do {
			    if (c == '_') {
				if (nondigit) break;
				nondigit = c;
				continue;
			    }
			    if (!ISXDIGIT(c)) break;
			    nondigit = 0;
			    tokadd(c);
			} while (c = nextc());
		    }
		    pushback(c);
		    tokfix();
		    if (toklen() == start) {
			yyerror("hexadecimal number without hex-digits");
		    }
		    else if (nondigit) goto trailing_uc;
		    yylval.val = rb_cstr2inum(tok(), 16);
		    return tINTEGER;
		}
		if (c == 'b' || c == 'B') {
		    /* binary */
		    c = nextc();
		    if (c == '0' || c == '1') {
			do {
			    if (c == '_') {
				if (nondigit) break;
				nondigit = c;
				continue;
			    }
			    if (c != '0' && c != '1') break;
			    nondigit = 0;
			    tokadd(c);
			} while (c = nextc());
		    }
		    pushback(c);
		    tokfix();
		    if (toklen() == start) {
			yyerror("numeric literal without digits");
		    }
		    else if (nondigit) goto trailing_uc;
		    yylval.val = rb_cstr2inum(tok(), 2);
		    return tINTEGER;
		}
		if (c >= '0' && c <= '7' || c == '_') {
		    /* octal */
	            do {
			if (c == '_') {
			    if (nondigit) break;
			    nondigit = c;
			    continue;
			}
			if (c < '0' || c > '7') break;
			nondigit = 0;
			tokadd(c);
		    } while (c = nextc());
		    if (toklen() > start) {
			pushback(c);
			tokfix();
			if (nondigit) goto trailing_uc;
			yylval.val = rb_cstr2inum(tok(), 8);
			return tINTEGER;
		    }
		    if (nondigit) {
			pushback(c);
			goto trailing_uc;
		    }
		}
		if (c > '7' && c <= '9') {
		    yyerror("Illegal octal digit");
		}
		else if (c == '.' || c == 'e' || c == 'E') {
		    tokadd('0');
		}
		else {
		    pushback(c);
		    yylval.val = INT2FIX(0);
		    return tINTEGER;
		}
	    }

	    for (;;) {
		switch (c) {
		  case '0': case '1': case '2': case '3': case '4':
		  case '5': case '6': case '7': case '8': case '9':
		    nondigit = 0;
		    tokadd(c);
		    break;

		  case '.':
		    if (nondigit) goto trailing_uc;
		    if (seen_point || seen_e) {
			goto decode_num;
		    }
		    else {
			int c0 = nextc();
			if (!ISDIGIT(c0)) {
			    pushback(c0);
			    goto decode_num;
			}
			c = c0;
		    }
		    tokadd('.');
		    tokadd(c);
		    is_float++;
		    seen_point++;
		    nondigit = 0;
		    break;

		  case 'e':
		  case 'E':
		    if (nondigit) {
			pushback(c);
			c = nondigit;
			goto decode_num;
		    }
		    if (seen_e) {
			goto decode_num;
		    }
		    tokadd(c);
		    seen_e++;
		    is_float++;
		    nondigit = c;
		    c = nextc();
		    if (c != '-' && c != '+') continue;
		    tokadd(c);
		    nondigit = c;
		    break;

		  case '_':	/* `_' in number just ignored */
		    if (nondigit) goto decode_num;
		    nondigit = c;
		    break;

		  default:
		    goto decode_num;
		}
		c = nextc();
	    }

	  decode_num:
	    pushback(c);
	    tokfix();
	    if (nondigit) {
		char tmp[30];
	      trailing_uc:
		sprintf(tmp, "trailing `%c' in number", nondigit);
		yyerror(tmp);
	    }
	    if (is_float) {
		double d = strtod(tok(), 0);
		if (errno == ERANGE) {
		    rb_warn("Float %s out of range", tok());
		    errno = 0;
		}
		yylval.val = rb_float_new(d);
		return tFLOAT;
	    }
	    yylval.val = rb_cstr2inum(tok(), 10);
	    return tINTEGER;
	}

      case ']':
      case '}':
	lex_state = EXPR_END;
	return c;

      case ')':
	if (cond_nest > 0) {
	    cond_stack >>= 1;
	}
	lex_state = EXPR_END;
	return c;

      case ':':
	c = nextc();
	if (c == ':') {
	    if (lex_state == EXPR_BEG ||  lex_state == EXPR_MID ||
		(lex_state == EXPR_ARG && space_seen)) {
		lex_state = EXPR_BEG;
		return tCOLON3;
	    }
	    lex_state = EXPR_DOT;
	    return tCOLON2;
	}
	pushback(c);
	if (lex_state == EXPR_END || ISSPACE(c)) {
	    lex_state = EXPR_BEG;
	    return ':';
	}
	lex_state = EXPR_FNAME;
	return tSYMBEG;

      case '/':
	if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
	    return parse_regx('/', '/');
	}
	if ((c = nextc()) == '=') {
	    yylval.id = '/';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	pushback(c);
	if (lex_state == EXPR_ARG && space_seen) {
	    if (!ISSPACE(c)) {
		arg_ambiguous();
		return parse_regx('/', '/');
	    }
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	return '/';

      case '^':
	if ((c = nextc()) == '=') {
	    yylval.id = '^';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	pushback(c);
	return '^';

      case ',':
      case ';':
	lex_state = EXPR_BEG;
	return c;

      case '~':
	if (lex_state == EXPR_FNAME || lex_state == EXPR_DOT) {
	    if ((c = nextc()) != '@') {
		pushback(c);
	    }
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	return '~';

      case '(':
	if (cond_nest > 0) {
	    cond_stack = (cond_stack<<1)|0;
	}
	if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
	    c = tLPAREN;
	}
	else if (lex_state == EXPR_ARG && space_seen) {
	    rb_warning("%s (...) interpreted as method call", tok());
	}
	lex_state = EXPR_BEG;
	return c;

      case '[':
	if (lex_state == EXPR_FNAME || lex_state == EXPR_DOT) {
	    lex_state = EXPR_ARG;
	    if ((c = nextc()) == ']') {
		if ((c = nextc()) == '=') {
		    return tASET;
		}
		pushback(c);
		return tAREF;
	    }
	    pushback(c);
	    return '[';
	}
	else if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
	    c = tLBRACK;
	}
	else if (lex_state == EXPR_ARG && space_seen) {
	    c = tLBRACK;
	}
	lex_state = EXPR_BEG;
	return c;

      case '{':
	if (lex_state != EXPR_END && lex_state != EXPR_ARG)
	    c = tLBRACE;
	lex_state = EXPR_BEG;
	return c;

      case '\\':
	c = nextc();
	if (c == '\n') {
	    space_seen = 1;
	    goto retry; /* skip \\n */
	}
	pushback(c);
	return '\\';

      case '%':
	if (lex_state == EXPR_BEG || lex_state == EXPR_MID) {
	    int term;
	    int paren;

	    c = nextc();
	  quotation:
	    if (!ISALNUM(c)) {
		term = c;
		c = 'Q';
	    }
	    else {
		term = nextc();
		if (ISALNUM(term) || ismbchar(term)) {
		    yyerror("unknown type of %string");
		    return 0;
		}
	    }
	    if (c == -1 || term == -1) {
		rb_compile_error("unterminated quoted string meets end of file");
		return 0;
	    }
	    paren = term;
	    if (term == '(') term = ')';
	    else if (term == '[') term = ']';
	    else if (term == '{') term = '}';
	    else if (term == '<') term = '>';
	    else paren = 0;

	    switch (c) {
	      case 'Q':
		return parse_string('"', term, paren);

	      case 'q':
		return parse_qstring(term, paren);

	      case 'w':
		return parse_quotedwords(term, paren);

	      case 'x':
		return parse_string('`', term, paren);

	      case 'r':
		return parse_regx(term, paren);

	      default:
		yyerror("unknown type of %string");
		return 0;
	    }
	}
	if ((c = nextc()) == '=') {
	    yylval.id = '%';
	    lex_state = EXPR_BEG;
	    return tOP_ASGN;
	}
	if (lex_state == EXPR_ARG && space_seen && !ISSPACE(c)) {
	    goto quotation;
	}
	switch (lex_state) {
	  case EXPR_FNAME: case EXPR_DOT:
	    lex_state = EXPR_ARG; break;
	  default:
	    lex_state = EXPR_BEG; break;
	}
	pushback(c);
	return '%';

      case '$':
	lex_state = EXPR_END;
	newtok();
	c = nextc();
	switch (c) {
	  case '_':		/* $_: last read line string */
	    c = nextc();
	    if (is_identchar(c)) {
		tokadd('$');
		tokadd('_');
		break;
	    }
	    pushback(c);
	    c = '_';
	    /* fall through */
	  case '~':		/* $~: match-data */
	    local_cnt(c);
	    /* fall through */
	  case '*':		/* $*: argv */
	  case '$':		/* $$: pid */
	  case '?':		/* $?: last status */
	  case '!':		/* $!: error string */
	  case '@':		/* $@: error position */
	  case '/':		/* $/: input record separator */
	  case '\\':		/* $\: output record separator */
	  case ';':		/* $;: field separator */
	  case ',':		/* $,: output field separator */
	  case '.':		/* $.: last read line number */
	  case '=':		/* $=: ignorecase */
	  case ':':		/* $:: load path */
	  case '<':		/* $<: reading filename */
	  case '>':		/* $>: default output handle */
	  case '\"':		/* $": already loaded files */
	    tokadd('$');
	    tokadd(c);
	    tokfix();
	    yylval.id = rb_intern(tok());
	    return tGVAR;

	  case '-':
	    tokadd('$');
	    tokadd(c);
	    c = nextc();
	    tokadd(c);
	    tokfix();
	    yylval.id = rb_intern(tok());
	    /* xxx shouldn't check if valid option variable */
	    return tGVAR;

	  case '&':		/* $&: last match */
	  case '`':		/* $`: string before last match */
	  case '\'':		/* $': string after last match */
	  case '+':		/* $+: string matches last paren. */
	    yylval.node = NEW_BACK_REF(c);
	    return tBACK_REF;

	  case '1': case '2': case '3':
	  case '4': case '5': case '6':
	  case '7': case '8': case '9':
	    tokadd('$');
	    while (ISDIGIT(c)) {
		tokadd(c);
		c = nextc();
	    }
	    if (is_identchar(c))
		break;
	    pushback(c);
	    tokfix();
	    yylval.node = NEW_NTH_REF(atoi(tok()+1));
	    return tNTH_REF;

	  default:
	    if (!is_identchar(c)) {
		pushback(c);
		return '$';
	    }
	  case '0':
	    tokadd('$');
	}
	break;

      case '@':
	c = nextc();
	newtok();
	tokadd('@');
	if (c == '@') {
	    tokadd('@');
	    c = nextc();
	}
	if (ISDIGIT(c)) {
	    if (tokidx == 1) {
		rb_compile_error("`@%c' is not a valid instance variable name", c);
	    }
	    else {
		rb_compile_error("`@@%c' is not a valid class variable name", c);
	    }
	}
	if (!is_identchar(c)) {
	    pushback(c);
	    return '@';
	}
	break;

      default:
	if (!is_identchar(c) || ISDIGIT(c)) {
	    rb_compile_error("Invalid char `\\%03o' in expression", c);
	    goto retry;
	}

	newtok();
	break;
    }

    while (is_identchar(c)) {
	tokadd(c);
	if (ismbchar(c)) {
	    int i, len = mbclen(c)-1;

	    for (i = 0; i < len; i++) {
		c = nextc();
		tokadd(c);
	    }
	}
	c = nextc();
    }
    if ((c == '!' || c == '?') && is_identchar(tok()[0]) && !peek('=')) {
	tokadd(c);
    }
    else {
	pushback(c);
    }
    tokfix();

    {
	int result = 0;

	switch (tok()[0]) {
	  case '$':
	    lex_state = EXPR_END;
	    result = tGVAR;
	    break;
	  case '@':
	    lex_state = EXPR_END;
	    if (tok()[1] == '@')
		result = tCVAR;
	    else
		result = tIVAR;
	    break;
	  default:
	    if (lex_state != EXPR_DOT) {
		/* See if it is a reserved word.  */
		kw = rb_reserved_word(tok(), toklen());
		if (kw) {
		    enum lex_state state = lex_state;
		    lex_state = kw->state;
		    if (state == EXPR_FNAME) {
			yylval.id = rb_intern(kw->name);
		    }
		    if (kw->id[0] == kDO) {
			if (COND_P()) return kDO_COND;
			if (CMDARG_P()) return kDO_BLOCK;
			return kDO;
		    }
		    if (state == EXPR_BEG)
			return kw->id[0];
		    else {
			if (kw->id[0] != kw->id[1])
			    lex_state = EXPR_BEG;
			return kw->id[1];
		    }
		}
	    }

	    if (toklast() == '!' || toklast() == '?') {
		result = tFID;
	    }
	    else {
		if (lex_state == EXPR_FNAME) {
#if 0
		    if ((c = nextc()) == '=' && !peek('=') && !peek('~') && !peek('>')) {
#else
		    if ((c = nextc()) == '=' && !peek('~') && !peek('>') &&
			(!peek('=') || lex_p + 1 < lex_pend && lex_p[1] == '>')) {
#endif
			result = tIDENTIFIER;
			tokadd(c);
		    }
		    else {
			pushback(c);
		    }
		}
		if (result == 0 && ISUPPER(tok()[0])) {
		    result = tCONSTANT;
		}
		else {
		    result = tIDENTIFIER;
		}
	    }
	    if (lex_state == EXPR_BEG ||
		lex_state == EXPR_DOT ||
		lex_state == EXPR_ARG) {
		lex_state = EXPR_ARG;
	    }
	    else {
		lex_state = EXPR_END;
	    }
	}
	tokfix();
	yylval.id = rb_intern(tok());
	return result;
    }
}

static NODE*
str_extend(list, term, paren)
    NODE *list;
    int term, paren;
{
    int c;
    int brace = -1;
    VALUE ss;
    NODE *node;
    int brace_nest = 0;
    int paren_nest = 0;
    int start;

    c = nextc();
    switch (c) {
      case '$':
      case '@':
      case '{':
	break;
      default:
	tokadd('#');
	pushback(c);
	return list;
    }

    start = ruby_sourceline;
    ss = rb_str_new(tok(), toklen());
    if (list == 0) {
	list = NEW_DSTR(ss);
    }
    else if (toklen() > 0) {
	list_append(list, NEW_STR(ss));
    }
    newtok();

    switch (c) {
      case '$':
	tokadd('$');
	c = nextc();
	if (c == -1) return (NODE*)-1;
	switch (c) {
	  case '1': case '2': case '3':
	  case '4': case '5': case '6':
	  case '7': case '8': case '9':
	    while (ISDIGIT(c)) {
		tokadd(c);
		c = nextc();
	    }
	    pushback(c);
	    goto fetch_id;

	  case '&': case '+':
	  case '_': case '~':
	  case '*': case '$': case '?':
	  case '!': case '@': case ',':
	  case '.': case '=': case ':':
	  case '<': case '>': case '\\':
	  case ';':
	  refetch:
	    tokadd(c);
	    goto fetch_id;

	  case '-':
	    tokadd(c);
	    c = nextc();
	    if (!is_identchar(c)) {
		pushback(c);
		goto invalid_interporate;
	    }
	    tokadd(c);
	    goto fetch_id;

          default:
	    if (c == term) {
		list_append(list, NEW_STR(rb_str_new2("#$")));
		pushback(c);
		newtok();
		return list;
	    }
	    switch (c) {
	      case '\"':
	      case '/':
	      case '\'':
	      case '`':
		goto refetch;
	    }
	    if (!is_identchar(c)) {
	      pushback(c);
	      invalid_interporate:
		{
		    VALUE s = rb_str_new2("#");
		    rb_str_cat(s, tok(), toklen());
		    list_append(list, NEW_STR(s));
		    newtok();
		    return list;
		}
	    }
	}

	while (is_identchar(c)) {
	    tokadd(c);
	    if (ismbchar(c)) {
		int i, len = mbclen(c)-1;

		for (i = 0; i < len; i++) {
		    c = nextc();
		    tokadd(c);
		}
	    }
	    c = nextc();
	}
	pushback(c);
	break;

      case '@':
	tokadd(c);
	c = nextc();
        if (c == '@') {
	    tokadd(c);
	    c = nextc();
        }
	while (is_identchar(c)) {
	    tokadd(c);
	    if (ismbchar(c)) {
		int i, len = mbclen(c)-1;

		for (i = 0; i < len; i++) {
		    c = nextc();
		    tokadd(c);
		}
	    }
	    c = nextc();
	}
	pushback(c);
	if (toklen() == 1) {
	    goto invalid_interporate;
	}
	break;

      case '{':
	if (c == '{') brace = '}';
	brace_nest = 1;
	do {
	  loop_again:
	    c = nextc();
	    switch (c) {
	      case -1:
		if (brace_nest > 1) {
		    yyerror("bad substitution in string");
		    newtok();
		    return list;
		}
		return (NODE*)-1;
	      case '}':
		if (c == brace) {
		    brace_nest--;
		    if (brace_nest == 0) break;
		}
		tokadd(c);
		goto loop_again;
	      case '\\':
		c = nextc();
		if (c == -1) return (NODE*)-1;
		if (c == term) {
		    tokadd(c);
		}
		else {
		    tokadd('\\');
		    tokadd(c);
		}
		goto loop_again;
	      case '{':
		if (brace != -1) brace_nest++;
	      default:
		/* within brace */
		if (brace_nest > 0) {
		    if (ismbchar(c)) {
			int i, len = mbclen(c)-1;

			for (i = 0; i < len; i++) {
			    tokadd(c);
			    c = nextc();
			}
		    }
		    tokadd(c);
		    break;
		}
		/* out of brace */
		if (c == paren) paren_nest++;
		else if (c == term && (!paren || paren_nest-- == 0)) {
		    pushback(c);
		    list_append(list, NEW_STR(rb_str_new2("#{")));
		    rb_warning("bad substitution in string");
		    tokfix();
		    list_append(list, NEW_STR(rb_str_new(tok(), toklen())));
		    newtok();
		    return list;
		}
		break;
	      case '\n':
		tokadd(c);
		break;
	    }
	} while (c != brace);
    }

  fetch_id:
    tokfix();
    node = NEW_EVSTR(tok(),toklen());
    nd_set_line(node, start);
    list_append(list, node);
    newtok();

    return list;
}

NODE*
rb_node_newnode(type, a0, a1, a2)
    enum node_type type;
    NODE *a0, *a1, *a2;
{
    NODE *n = (NODE*)rb_newobj();

    n->flags |= T_NODE;
    nd_set_type(n, type);
    nd_set_line(n, ruby_sourceline);
    n->nd_file = ruby_sourcefile;

    n->u1.node = a0;
    n->u2.node = a1;
    n->u3.node = a2;

    return n;
}

static enum node_type
nodetype(node)			/* for debug */
    NODE *node;
{
    return (enum node_type)nd_type(node);
}

static int
nodeline(node)
    NODE *node;
{
    return nd_line(node);
}

static NODE*
newline_node(node)
    NODE *node;
{
    NODE *nl = 0;
    if (node) {
        nl = NEW_NEWLINE(node);
        fixpos(nl, node);
        nl->nd_nth = nd_line(node);
    }
    return nl;
}

static void
fixpos(node, orig)
    NODE *node, *orig;
{
    if (!node) return;
    if (!orig) return;
    if (orig == (NODE*)1) return;
    node->nd_file = orig->nd_file;
    nd_set_line(node, nd_line(orig));
}

static NODE*
block_append(head, tail)
    NODE *head, *tail;
{
    NODE *end;

    if (tail == 0) return head;
    if (head == 0) return tail;

    if (nd_type(head) != NODE_BLOCK) {
	end = NEW_BLOCK(head);
	end->nd_end = end;
	fixpos(end, head);
	head = end;
    }
    else {
	end = head->nd_end;
    }

    if (RTEST(ruby_verbose)) {
	NODE *nd = end->nd_head;
      newline:
	switch (nd_type(nd)) {
	  case NODE_RETURN:
	  case NODE_BREAK:
	  case NODE_NEXT:
	  case NODE_REDO:
	  case NODE_RETRY:
	    rb_warning("statement not reached");
	    break;

	case NODE_NEWLINE:
	    nd = nd->nd_next;
	    goto newline;

	  default:
	    break;
	}
    }

    if (nd_type(tail) != NODE_BLOCK) {
	tail = NEW_BLOCK(tail);
	tail->nd_end = tail;
    }
    end->nd_next = tail;
    head->nd_end = tail->nd_end;
    return head;
}

static NODE*
list_append(head, tail)
    NODE *head, *tail;
{
    NODE *last;

    if (head == 0) return NEW_LIST(tail);

    last = head;
    while (last->nd_next) {
	last = last->nd_next;
    }

    last->nd_next = NEW_LIST(tail);
    head->nd_alen += 1;
    return head;
}

static NODE*
list_concat(head, tail)
    NODE *head, *tail;
{
    NODE *last;

    last = head;
    while (last->nd_next) {
	last = last->nd_next;
    }

    last->nd_next = tail;
    head->nd_alen += tail->nd_alen;

    return head;
}

static NODE *
call_op(recv, id, narg, arg1)
    NODE *recv;
    ID id;
    int narg;
    NODE *arg1;
{
    value_expr(recv);
    if (narg == 1) {
	value_expr(arg1);
    }

    return NEW_CALL(recv, id, narg==1?NEW_LIST(arg1):0);
}

static NODE*
match_gen(node1, node2)
    NODE *node1;
    NODE *node2;
{
    local_cnt('~');

    value_expr(node1);
    value_expr(node2);
    if (node1) {
	switch (nd_type(node1)) {
	  case NODE_DREGX:
	  case NODE_DREGX_ONCE:
	    return NEW_MATCH2(node1, node2);

	  case NODE_LIT:
	    if (TYPE(node1->nd_lit) == T_REGEXP) {
		return NEW_MATCH2(node1, node2);
	    }
	}
    }

    if (node2) {
	switch (nd_type(node2)) {
	  case NODE_DREGX:
	  case NODE_DREGX_ONCE:
	    return NEW_MATCH3(node2, node1);

	  case NODE_LIT:
	    if (TYPE(node2->nd_lit) == T_REGEXP) {
		return NEW_MATCH3(node2, node1);
	    }
	}
    }

    return NEW_CALL(node1, tMATCH, NEW_LIST(node2));
}

static NODE*
gettable(id)
    ID id;
{
    if (id == kSELF) {
	return NEW_SELF();
    }
    else if (id == kNIL) {
	return NEW_NIL();
    }
    else if (id == kTRUE) {
	return NEW_TRUE();
    }
    else if (id == kFALSE) {
	return NEW_FALSE();
    }
    else if (id == k__FILE__) {
	return NEW_STR(rb_str_new2(ruby_sourcefile));
    }
    else if (id == k__LINE__) {
	return NEW_LIT(INT2FIX(ruby_sourceline));
    }
    else if (is_local_id(id)) {
	if (dyna_in_block() && rb_dvar_defined(id)) return NEW_DVAR(id);
	if (local_id(id)) return NEW_LVAR(id);
	/* method call without arguments */
	return NEW_VCALL(id);
    }
    else if (is_global_id(id)) {
	return NEW_GVAR(id);
    }
    else if (is_instance_id(id)) {
	return NEW_IVAR(id);
    }
    else if (is_const_id(id)) {
	return NEW_CONST(id);
    }
    else if (is_class_id(id)) {
	return NEW_CVAR(id);
    }
    rb_bug("invalid id for gettable");
    return 0;
}

static NODE*
assignable(id, val)
    ID id;
    NODE *val;
{
    value_expr(val);
    if (id == kSELF) {
	yyerror("Can't change the value of self");
    }
    else if (id == kNIL) {
	yyerror("Can't assign to nil");
    }
    else if (id == kTRUE) {
	yyerror("Can't assign to true");
    }
    else if (id == kFALSE) {
	yyerror("Can't assign to false");
    }
    else if (id == k__FILE__) {
	yyerror("Can't assign to __FILE__");
    }
    else if (id == k__LINE__) {
	yyerror("Can't assign to __LINE__");
    }
    else if (is_local_id(id)) {
	if (rb_dvar_curr(id)) {
	    return NEW_DASGN_CURR(id, val);
	}
	else if (rb_dvar_defined(id)) {
	    return NEW_DASGN(id, val);
	}
	else if (local_id(id) || !dyna_in_block()) {
	    return NEW_LASGN(id, val);
	}
	else{
	    rb_dvar_push(id, Qnil);
	    return NEW_DASGN_CURR(id, val);
	}
    }
    else if (is_global_id(id)) {
	return NEW_GASGN(id, val);
    }
    else if (is_instance_id(id)) {
	return NEW_IASGN(id, val);
    }
    else if (is_const_id(id)) {
	if (in_def || in_single)
	    yyerror("dynamic constant assignment");
	return NEW_CDECL(id, val);
    }
    else if (is_class_id(id)) {
	if (in_def || in_single) return NEW_CVASGN(id, val);
	return NEW_CVDECL(id, val);
    }
    else {
	rb_bug("bad id for variable");
    }
    return 0;
}

static NODE *
aryset(recv, idx)
    NODE *recv, *idx;
{
    value_expr(recv);
    return NEW_CALL(recv, tASET, idx);
}

ID
rb_id_attrset(id)
    ID id;
{
    id &= ~ID_SCOPE_MASK;
    id |= ID_ATTRSET;
    return id;
}

static NODE *
attrset(recv, id)
    NODE *recv;
    ID id;
{
    value_expr(recv);
    return NEW_CALL(recv, rb_id_attrset(id), 0);
}

static void
rb_backref_error(node)
    NODE *node;
{
    switch (nd_type(node)) {
      case NODE_NTH_REF:
	rb_compile_error("Can't set variable $%d", (int)node->nd_nth);
	break;
      case NODE_BACK_REF:
	rb_compile_error("Can't set variable $%c", (int)node->nd_nth);
	break;
    }
}

static NODE *
arg_concat(node1, node2)
    NODE *node1;
    NODE *node2;
{
    if (!node2) return node1;
    return NEW_ARGSCAT(node1, node2);
}

static NODE *
arg_add(node1, node2)
    NODE *node1;
    NODE *node2;
{
    if (!node1) return NEW_LIST(node2);
    if (nd_type(node1) == NODE_ARRAY) {
	return list_append(node1, node2);
    }
    else {
	return NEW_ARGSPUSH(node1, node2);
    }
}

static NODE*
node_assign(lhs, rhs)
    NODE *lhs, *rhs;
{
    if (!lhs) return 0;

    value_expr(rhs);
    switch (nd_type(lhs)) {
      case NODE_GASGN:
      case NODE_IASGN:
      case NODE_LASGN:
      case NODE_DASGN:
      case NODE_DASGN_CURR:
      case NODE_MASGN:
      case NODE_CDECL:
      case NODE_CVDECL:
      case NODE_CVASGN:
	lhs->nd_value = rhs;
	break;

      case NODE_CALL:
	lhs->nd_args = arg_add(lhs->nd_args, rhs);
	break;

      default:
	/* should not happen */
	break;
    }

    if (rhs) fixpos(lhs, rhs);
    return lhs;
}

static int
value_expr0(node)
    NODE *node;
{
    int cond = 0;

    while (node) {
	switch (nd_type(node)) {
	  case NODE_RETURN:
	  case NODE_BREAK:
	  case NODE_NEXT:
	  case NODE_REDO:
	  case NODE_RETRY:
	  case NODE_WHILE:
	  case NODE_UNTIL:
	  case NODE_CLASS:
	  case NODE_MODULE:
	  case NODE_DEFN:
	  case NODE_DEFS:
	    if (!cond) yyerror("void value expression");
	    return Qfalse;

	  case NODE_BLOCK:
	    while (node->nd_next) {
		node = node->nd_next;
	    }
	    node = node->nd_head;
	    break;

	  case NODE_BEGIN:
	    node = node->nd_body;
	    break;

	  case NODE_IF:
	    if (!value_expr(node->nd_body)) return Qfalse;
	    node = node->nd_else;
	    break;

	  case NODE_AND:
	  case NODE_OR:
	    cond = 1;
	    node = node->nd_2nd;
	    break;

	  case NODE_NEWLINE:
	    node = node->nd_next;
	    break;

	  default:
	    return Qtrue;
	}
    }
    return Qtrue;
}

static void
void_expr0(node)
    NODE *node;
{
    char *useless = 0;

    if (!RTEST(ruby_verbose)) return;
    if (!node) return;

  again:
    switch (nd_type(node)) {
      case NODE_NEWLINE:
	node = node->nd_next;
	goto again;

      case NODE_CALL:
	switch (node->nd_mid) {
	  case '+':
	  case '-':
	  case '*':
	  case '/':
	  case '%':
	  case tPOW:
	  case tUPLUS:
	  case tUMINUS:
	  case '|':
	  case '^':
	  case '&':
	  case tCMP:
	  case '>':
	  case tGEQ:
	  case '<':
	  case tLEQ:
	  case tEQ:
	  case tNEQ:
	    useless = rb_id2name(node->nd_mid);
	    break;
	}
	break;

      case NODE_LVAR:
      case NODE_DVAR:
      case NODE_GVAR:
      case NODE_IVAR:
      case NODE_CVAR:
      case NODE_NTH_REF:
      case NODE_BACK_REF:
	useless = "a variable";
	break;
      case NODE_CONST:
      case NODE_CREF:
	useless = "a constant";
	break;
      case NODE_LIT:
      case NODE_STR:
      case NODE_DSTR:
      case NODE_DREGX:
      case NODE_DREGX_ONCE:
	useless = "a literal";
	break;
      case NODE_COLON2:
      case NODE_COLON3:
	useless = "::";
	break;
      case NODE_DOT2:
	useless = "..";
	break;
      case NODE_DOT3:
	useless = "...";
	break;
      case NODE_SELF:
	useless = "self";
	break;
      case NODE_NIL:
	useless = "nil";
	break;
      case NODE_TRUE:
	useless = "true";
	break;
      case NODE_FALSE:
	useless = "false";
	break;
      case NODE_DEFINED:
	useless = "defined?";
	break;
    }

    if (useless) {
	int line = ruby_sourceline;

	ruby_sourceline = nd_line(node);
	rb_warn("useless use of %s in void context", useless);
	ruby_sourceline = line;
    }
}


static NODE *cond2 _((NODE*));

static void
void_stmts(node)
    NODE *node;
{
    if (!RTEST(ruby_verbose)) return;
    if (!node) return;
    if (nd_type(node) != NODE_BLOCK) return;

    for (;;) {
	if (!node->nd_next) return;
	void_expr(node->nd_head);
	node = node->nd_next;
    }
}

static NODE *
remove_begin(node)
    NODE *node;
{
    NODE **n = &node;
    while (*n) {
	switch (nd_type(*n)) {
	  case NODE_NEWLINE:
	    n = &(*n)->nd_next;
	    continue;
	  case NODE_BEGIN:
	    *n = (*n)->nd_body;
	  default:
	    return node;
	}
    }
    return node;
}

static int
assign_in_cond(node)
    NODE *node;
{
    switch (nd_type(node)) {
      case NODE_MASGN:
	yyerror("multiple assignment in conditional");
	return 1;

      case NODE_LASGN:
      case NODE_DASGN:
      case NODE_GASGN:
      case NODE_IASGN:
	break;

      case NODE_NEWLINE:
      default:
	return 0;
    }

    switch (nd_type(node->nd_value)) {
      case NODE_LIT:
      case NODE_STR:
      case NODE_NIL:
      case NODE_TRUE:
      case NODE_FALSE:
	/* reports always */
	rb_warn("found = in conditional, should be ==");
	return 1;

      case NODE_DSTR:
      case NODE_XSTR:
      case NODE_DXSTR:
      case NODE_EVSTR:
      case NODE_DREGX:
      default:
	break;
    }
#if 0
    if (assign_in_cond(node->nd_value) == 0) {
	rb_warning("assignment in condition");
    }
#endif
    return 1;
}

static NODE*
cond0(node)
    NODE *node;
{
    enum node_type type = nd_type(node);

    assign_in_cond(node);
    switch (type) {
      case NODE_DREGX:
      case NODE_DREGX_ONCE:
	local_cnt('_');
	local_cnt('~');
	return NEW_MATCH2(node, NEW_GVAR(rb_intern("$_")));

      case NODE_DOT2:
      case NODE_DOT3:
	node->nd_beg = cond2(node->nd_beg);
	node->nd_end = cond2(node->nd_end);
	if (type == NODE_DOT2) nd_set_type(node,NODE_FLIP2);
	else if (type == NODE_DOT3) nd_set_type(node, NODE_FLIP3);
	node->nd_cnt = local_append(0);
	return node;

      case NODE_LIT:
	if (TYPE(node->nd_lit) == T_REGEXP) {
	    local_cnt('_');
	    local_cnt('~');
	    return NEW_MATCH(node);
	}
	if (TYPE(node->nd_lit) == T_STRING) {
	    local_cnt('_');
	    local_cnt('~');
	    return NEW_MATCH(rb_reg_new(RSTRING(node)->ptr,RSTRING(node)->len,0));
	}
      default:
	return node;
    }
}

static NODE*
cond(node)
    NODE *node;
{
    if (node == 0) return 0;
    if (nd_type(node) == NODE_NEWLINE){
	node->nd_next = cond0(node->nd_next);
	return node;
    }
    return cond0(node);
}

static NODE*
cond2(node)
    NODE *node;
{
    enum node_type type;

    if (!node) return node;
    node = cond(node);
    type = nd_type(node);
    if (type == NODE_NEWLINE) node = node->nd_next;
    if (type == NODE_LIT && FIXNUM_P(node->nd_lit)) {
	return call_op(node,tEQ,1,NEW_GVAR(rb_intern("$.")));
    }
    return node;
}

static NODE*
logop(type, left, right)
    enum node_type type;
    NODE *left, *right;
{
    value_expr(left);
    return rb_node_newnode(type, cond(left), cond(right), 0);
}

static NODE *
arg_blk_pass(node1, node2)
    NODE *node1;
    NODE *node2;
{
    if (node2) {
	node2->nd_head = node1;
	return node2;
    }
    return node1;
}

static NODE*
new_call(r,m,a)
    NODE *r;
    ID m;
    NODE *a;
{
    if (a && nd_type(a) == NODE_BLOCK_PASS) {
	a->nd_iter = NEW_CALL(r,m,a->nd_head);
	return a;
    }
    return NEW_CALL(r,m,a);
}

static NODE*
new_fcall(m,a)
    ID m;
    NODE *a;
{
    if (a && nd_type(a) == NODE_BLOCK_PASS) {
	a->nd_iter = NEW_FCALL(m,a->nd_head);
	return a;
    }
    return NEW_FCALL(m,a);
}

static NODE*
new_super(a)
    NODE *a;
{
    if (a && nd_type(a) == NODE_BLOCK_PASS) {
	a->nd_iter = NEW_SUPER(a->nd_head);
	return a;
    }
    return NEW_SUPER(a);
}

static struct local_vars {
    ID *tbl;
    int nofree;
    int cnt;
    int dlev;
    struct RVarmap* dyna_vars;
    struct local_vars *prev;
} *lvtbl;

static void
local_push(top)
    int top;
{
    struct local_vars *local;

    local = ALLOC(struct local_vars);
    local->prev = lvtbl;
    local->nofree = 0;
    local->cnt = 0;
    local->tbl = 0;
    local->dlev = 0;
    local->dyna_vars = ruby_dyna_vars;
    lvtbl = local;
    if (!top) {
	/* preserve reference for GC, but link should be cut. */
	rb_dvar_push(0, (VALUE)ruby_dyna_vars);
	ruby_dyna_vars->next = 0;
    }
}

static void
local_pop()
{
    struct local_vars *local = lvtbl->prev;

    if (lvtbl->tbl) {
	if (!lvtbl->nofree) free(lvtbl->tbl);
	else lvtbl->tbl[0] = lvtbl->cnt;
    }
    ruby_dyna_vars = lvtbl->dyna_vars;
    free(lvtbl);
    lvtbl = local;
}

static ID*
local_tbl()
{
    lvtbl->nofree = 1;
    return lvtbl->tbl;
}

static int
local_append(id)
    ID id;
{
    if (lvtbl->tbl == 0) {
	lvtbl->tbl = ALLOC_N(ID, 4);
	lvtbl->tbl[0] = 0;
	lvtbl->tbl[1] = '_';
	lvtbl->tbl[2] = '~';
	lvtbl->cnt = 2;
	if (id == '_') return 0;
	if (id == '~') return 1;
    }
    else {
	REALLOC_N(lvtbl->tbl, ID, lvtbl->cnt+2);
    }

    lvtbl->tbl[lvtbl->cnt+1] = id;
    return lvtbl->cnt++;
}

static int
local_cnt(id)
    ID id;
{
    int cnt, max;

    if (id == 0) return lvtbl->cnt;

    for (cnt=1, max=lvtbl->cnt+1; cnt<max;cnt++) {
	if (lvtbl->tbl[cnt] == id) return cnt-1;
    }
    return local_append(id);
}

static int
local_id(id)
    ID id;
{
    int i, max;

    if (lvtbl == 0) return Qfalse;
    for (i=3, max=lvtbl->cnt+1; i<max; i++) {
	if (lvtbl->tbl[i] == id) return Qtrue;
    }
    return Qfalse;
}

static void
top_local_init()
{
    local_push(1);
    lvtbl->cnt = ruby_scope->local_tbl?ruby_scope->local_tbl[0]:0;
    if (lvtbl->cnt > 0) {
	lvtbl->tbl = ALLOC_N(ID, lvtbl->cnt+3);
	MEMCPY(lvtbl->tbl, ruby_scope->local_tbl, ID, lvtbl->cnt+1);
    }
    else {
	lvtbl->tbl = 0;
    }
    if (ruby_dyna_vars)
	lvtbl->dlev = 1;
    else
	lvtbl->dlev = 0;
}

static void
top_local_setup()
{
    int len = lvtbl->cnt;
    int i;

    if (len > 0) {
	i = ruby_scope->local_tbl?ruby_scope->local_tbl[0]:0;

	if (i < len) {
	    if (i == 0 || (ruby_scope->flag & SCOPE_MALLOC) == 0) {
		VALUE *vars = ALLOC_N(VALUE, len+1);
		if (ruby_scope->local_vars) {
		    *vars++ = ruby_scope->local_vars[-1];
		    MEMCPY(vars, ruby_scope->local_vars, VALUE, i);
		    rb_mem_clear(vars+i, len-i);
		}
		else {
		    *vars++ = 0;
		    rb_mem_clear(vars, len);
		}
		ruby_scope->local_vars = vars;
		ruby_scope->flag |= SCOPE_MALLOC;
	    }
	    else {
		VALUE *vars = ruby_scope->local_vars-1;
		REALLOC_N(vars, VALUE, len+1);
		ruby_scope->local_vars = vars+1;
		rb_mem_clear(ruby_scope->local_vars+i, len-i);
	    }
	    if (ruby_scope->local_tbl && ruby_scope->local_vars[-1] == 0) {
		free(ruby_scope->local_tbl);
	    }
	    ruby_scope->local_vars[-1] = 0;
	    ruby_scope->local_tbl = local_tbl();
	}
    }
    local_pop();
}

static struct RVarmap*
dyna_push()
{
    struct RVarmap* vars = ruby_dyna_vars;

    rb_dvar_push(0, 0);
    lvtbl->dlev++;
    return vars;
}

static void
dyna_pop(vars)
    struct RVarmap* vars;
{
    lvtbl->dlev--;
    ruby_dyna_vars = vars;
}

static int
dyna_in_block()
{
    return (lvtbl->dlev > 0);
}

int
ruby_parser_stack_on_heap()
{
#if defined(YYBISON) && !defined(C_ALLOCA)
    return Qfalse;
#else
    return Qtrue;
#endif
}

void
rb_gc_mark_parser()
{
    if (!ruby_in_compile) return;

    rb_gc_mark_maybe(yylval.val);
    rb_gc_mark(ruby_debug_lines);
    rb_gc_mark(lex_lastline);
    rb_gc_mark(lex_input);
}

void
rb_parser_append_print()
{
    ruby_eval_tree =
	block_append(ruby_eval_tree,
		     NEW_FCALL(rb_intern("print"),
			       NEW_ARRAY(NEW_GVAR(rb_intern("$_")))));
}

void
rb_parser_while_loop(chop, split)
    int chop, split;
{
    if (split) {
	ruby_eval_tree =
	    block_append(NEW_GASGN(rb_intern("$F"),
				   NEW_CALL(NEW_GVAR(rb_intern("$_")),
					    rb_intern("split"), 0)),
				   ruby_eval_tree);
    }
    if (chop) {
	ruby_eval_tree =
	    block_append(NEW_CALL(NEW_GVAR(rb_intern("$_")),
				  rb_intern("chop!"), 0), ruby_eval_tree);
    }
    ruby_eval_tree = NEW_OPT_N(ruby_eval_tree);
}

static struct {
    ID token;
    char *name;
} op_tbl[] = {
    tDOT2,	"..",
    tDOT3,	"...",
    '+',	"+",
    '-',	"-",
    '+',	"+(binary)",
    '-',	"-(binary)",
    '*',	"*",
    '/',	"/",
    '%',	"%",
    tPOW,	"**",
    tUPLUS,	"+@",
    tUMINUS,	"-@",
    tUPLUS,	"+(unary)",
    tUMINUS,	"-(unary)",
    '|',	"|",
    '^',	"^",
    '&',	"&",
    tCMP,	"<=>",
    '>',	">",
    tGEQ,	">=",
    '<',	"<",
    tLEQ,	"<=",
    tEQ,	"==",
    tEQQ,	"===",
    tNEQ,	"!=",
    tMATCH,	"=~",
    tNMATCH,	"!~",
    '!',	"!",
    '~',	"~",
    '!',	"!(unary)",
    '~',	"~(unary)",
    '!',	"!@",
    '~',	"~@",
    tAREF,	"[]",
    tASET,	"[]=",
    tLSHFT,	"<<",
    tRSHFT,	">>",
    tCOLON2,	"::",
    tCOLON3,	"::",
    '`',	"`",
    0,		0,
};

static st_table *sym_tbl;
static st_table *sym_rev_tbl;

void
Init_sym()
{
    sym_tbl = st_init_strtable_with_size(200);
    sym_rev_tbl = st_init_numtable_with_size(200);
}

ID
rb_intern(name)
    const char *name;
{
    static ID last_id = LAST_TOKEN;
    ID id;
    int last;

    if (st_lookup(sym_tbl, name, &id))
	return id;

    id = 0;
    switch (name[0]) {
      case '$':
	id |= ID_GLOBAL;
	break;
      case '@':
	if (name[1] == '@')
	    id |= ID_CLASS;
	else
	    id |= ID_INSTANCE;
	break;
      default:
	if (name[0] != '_' && !ISALPHA(name[0]) && !ismbchar(name[0])) {
	    /* operator */
	    int i;

	    for (i=0; op_tbl[i].token; i++) {
		if (*op_tbl[i].name == *name &&
		    strcmp(op_tbl[i].name, name) == 0) {
		    id = op_tbl[i].token;
		    goto id_regist;
		}
	    }
	}

	last = strlen(name)-1;
	if (name[last] == '=') {
	    /* attribute assignment */
	    char *buf = ALLOCA_N(char,last+1);

	    strncpy(buf, name, last);
	    buf[last] = '\0';
	    id = rb_intern(buf);
	    if (id > LAST_TOKEN && !is_attrset_id(id)) {
		id = rb_id_attrset(id);
		goto id_regist;
	    }
	    id = ID_ATTRSET;
	}
	else if (ISUPPER(name[0])) {
	    id = ID_CONST;
        }
	else {
	    id = ID_LOCAL;
	}
	break;
    }
    id |= ++last_id << ID_SCOPE_SHIFT;
  id_regist:
    name = strdup(name);
    st_add_direct(sym_tbl, name, id);
    st_add_direct(sym_rev_tbl, id, name);
    return id;
}

char *
rb_id2name(id)
    ID id;
{
    char *name;

    if (id < LAST_TOKEN) {
	int i = 0;

	for (i=0; op_tbl[i].token; i++) {
	    if (op_tbl[i].token == id)
		return op_tbl[i].name;
	}
    }

    if (st_lookup(sym_rev_tbl, id, &name))
	return name;

    if (is_attrset_id(id)) {
	ID id2 = (id & ~ID_SCOPE_MASK) | ID_LOCAL;

      again:
	name = rb_id2name(id2);
	if (name) {
	    char *buf = ALLOCA_N(char, strlen(name)+2);

	    strcpy(buf, name);
	    strcat(buf, "=");
	    rb_intern(buf);
	    return rb_id2name(id);
	}
	if (is_local_id(id2)) {
	    id2 = (id & ~ID_SCOPE_MASK) | ID_CONST;
	    goto again;
	}
    }
    return 0;
}

int
rb_is_const_id(id)
    ID id;
{
    if (is_const_id(id)) return Qtrue;
    return Qfalse;
}

int
rb_is_class_id(id)
    ID id;
{
    if (is_class_id(id)) return Qtrue;
    return Qfalse;
}

int
rb_is_instance_id(id)
    ID id;
{
    if (is_instance_id(id)) return Qtrue;
    return Qfalse;
}

static void
special_local_set(c, val)
    char c;
    VALUE val;
{
    int cnt;

    top_local_init();
    cnt = local_cnt(c);
    top_local_setup();
    ruby_scope->local_vars[cnt] = val;
}

VALUE
rb_backref_get()
{
    if (ruby_scope->local_vars) {
	return ruby_scope->local_vars[1];
    }
    return Qnil;
}

void
rb_backref_set(val)
    VALUE val;
{
    if (ruby_scope->local_vars) {
	ruby_scope->local_vars[1] = val;
    }
    else {
	special_local_set('~', val);
    }
}

VALUE
rb_lastline_get()
{
    if (ruby_scope->local_vars) {
	return ruby_scope->local_vars[0];
    }
    return Qnil;
}

void
rb_lastline_set(val)
    VALUE val;
{
    if (ruby_scope->local_vars) {
	ruby_scope->local_vars[0] = val;
    }
    else {
	special_local_set('_', val);
    }
}