yyparse: replace some gotos with a while(1) loop

[perl5.git] / perly.c

/*    perly.c
 *
 *    Copyright (c) 2004, 2005, 2006, 2007, 2008,
 *    2009, 2010, 2011 by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 * 
 *    Note that this file was originally generated as an output from
 *    GNU bison version 1.875, but now the code is statically maintained
 *    and edited; the bits that are dependent on perly.y are now
 *    #included from the files perly.tab and perly.act.
 *
 *    Here is an important copyright statement from the original, generated
 *    file:
 *
 *	As a special exception, when this file is copied by Bison into a
 *	Bison output file, you may use that output file without
 *	restriction.  This special exception was added by the Free
 *	Software Foundation in version 1.24 of Bison.
 *
 */

#include "EXTERN.h"
#define PERL_IN_PERLY_C
#include "perl.h"
#include "feature.h"
#include "keywords.h"

typedef unsigned char yytype_uint8;
typedef signed char yytype_int8;
typedef unsigned short int yytype_uint16;
typedef short int yytype_int16;
typedef signed char yysigned_char;

/* YYINITDEPTH -- initial size of the parser's stacks.  */
#define YYINITDEPTH 200

#ifdef YYDEBUG
#  undef YYDEBUG
#endif
#ifdef DEBUGGING
#  define YYDEBUG 1
#else
#  define YYDEBUG 0
#endif

#ifndef YY_NULL
# define YY_NULL 0
#endif

#ifndef YY_NULLPTR
# define YY_NULLPTR NULL
#endif

/* contains all the parser state tables; auto-generated from perly.y */
#include "perly.tab"

# define YYSIZE_T size_t

#define YYEOF		0
#define YYTERROR	1

#define YYACCEPT	goto yyacceptlab
#define YYABORT		goto yyabortlab
#define YYERROR		goto yyerrlab1

/* Enable debugging if requested.  */
#ifdef DEBUGGING

#  define yydebug (DEBUG_p_TEST)

#  define YYFPRINTF PerlIO_printf

#  define YYDPRINTF(Args)			\
do {						\
    if (yydebug)				\
	YYFPRINTF Args;				\
} while (0)

#  define YYDSYMPRINTF(Title, Token, Value)			\
do {								\
    if (yydebug) {						\
	YYFPRINTF (Perl_debug_log, "%s ", Title);		\
	yysymprint (aTHX_ Perl_debug_log,  Token, Value);	\
	YYFPRINTF (Perl_debug_log, "\n");			\
    }								\
} while (0)

/*--------------------------------.
| Print this symbol on YYOUTPUT.  |
`--------------------------------*/

static void
yysymprint(pTHX_ PerlIO * const yyoutput, int yytype, const YYSTYPE * const yyvaluep)
{
    PERL_UNUSED_CONTEXT;
    if (yytype < YYNTOKENS) {
	YYFPRINTF (yyoutput, "token %s (", yytname[yytype]);
#   ifdef YYPRINT
	YYPRINT (yyoutput, yytoknum[yytype], *yyvaluep);
#   else
	YYFPRINTF (yyoutput, "0x%" UVxf, (UV)yyvaluep->ival);
#   endif
    }
    else
	YYFPRINTF (yyoutput, "nterm %s (", yytname[yytype]);

    YYFPRINTF (yyoutput, ")");
}


/*  yy_stack_print()
 *  print the top 8 items on the parse stack.
 */

static void
yy_stack_print (pTHX_ const yy_parser *parser)
{
    const yy_stack_frame *ps, *min;

    min = parser->ps - 8 + 1;
    if (min <= parser->stack)
	min = parser->stack + 1;

    PerlIO_printf(Perl_debug_log, "\nindex:");
    for (ps = min; ps <= parser->ps; ps++)
	PerlIO_printf(Perl_debug_log, " %8d", (int)(ps - parser->stack));

    PerlIO_printf(Perl_debug_log, "\nstate:");
    for (ps = min; ps <= parser->ps; ps++)
	PerlIO_printf(Perl_debug_log, " %8d", ps->state);

    PerlIO_printf(Perl_debug_log, "\ntoken:");
    for (ps = min; ps <= parser->ps; ps++)
	PerlIO_printf(Perl_debug_log, " %8.8s", ps->name);

    PerlIO_printf(Perl_debug_log, "\nvalue:");
    for (ps = min; ps <= parser->ps; ps++) {
	switch (yy_type_tab[yystos[ps->state]]) {
	case toketype_opval:
	    PerlIO_printf(Perl_debug_log, " %8.8s",
		  ps->val.opval
		    ? PL_op_name[ps->val.opval->op_type]
		    : "(Nullop)"
	    );
	    break;
	case toketype_ival:
	    PerlIO_printf(Perl_debug_log, " %8" IVdf, (IV)ps->val.ival);
	    break;
	default:
	    PerlIO_printf(Perl_debug_log, " %8" UVxf, (UV)ps->val.ival);
	}
    }
    PerlIO_printf(Perl_debug_log, "\n\n");
}

#  define YY_STACK_PRINT(parser)	\
do {					\
    if (yydebug && DEBUG_v_TEST)	\
	yy_stack_print (aTHX_ parser);	\
} while (0)


/*------------------------------------------------.
| Report that the YYRULE is going to be reduced.  |
`------------------------------------------------*/

static void
yy_reduce_print (pTHX_ int yyrule)
{
    int yyi;
    const unsigned int yylineno = yyrline[yyrule];
    YYFPRINTF (Perl_debug_log, "Reducing stack by rule %d (line %u), ",
			  yyrule - 1, yylineno);
    /* Print the symbols being reduced, and their result.  */
#if PERL_BISON_VERSION >= 30000 /* 3.0+ */
    for (yyi = 0; yyi < yyr2[yyrule]; yyi++)
	YYFPRINTF (Perl_debug_log, "%s ",
            yytname [yystos[(PL_parser->ps)[yyi + 1 - yyr2[yyrule]].state]]);
#else
    for (yyi = yyprhs[yyrule]; 0 <= yyrhs[yyi]; yyi++)
	YYFPRINTF (Perl_debug_log, "%s ", yytname [yyrhs[yyi]]);
#endif
    YYFPRINTF (Perl_debug_log, "-> %s\n", yytname [yyr1[yyrule]]);
}

#  define YY_REDUCE_PRINT(Rule)		\
do {					\
    if (yydebug)			\
	yy_reduce_print (aTHX_ Rule);		\
} while (0)

#else /* !DEBUGGING */
#  define YYDPRINTF(Args)
#  define YYDSYMPRINTF(Title, Token, Value)
#  define YY_STACK_PRINT(parser)
#  define YY_REDUCE_PRINT(Rule)
#endif /* !DEBUGGING */

/* called during cleanup (via SAVEDESTRUCTOR_X) to free any items on the
 * parse stack, thus avoiding leaks if we die  */

static void
S_clear_yystack(pTHX_  const yy_parser *parser)
{
    yy_stack_frame *ps     = parser->ps;
    int i = 0;

    if (!parser->stack)
	return;

    YYDPRINTF ((Perl_debug_log, "clearing the parse stack\n"));

    for (i=0; i< parser->yylen; i++) {
	SvREFCNT_dec(ps[-i].compcv);
    }
    ps -= parser->yylen;

    /* now free whole the stack, including the just-reduced ops */

    while (ps > parser->stack) {
	LEAVE_SCOPE(ps->savestack_ix);
	if (yy_type_tab[yystos[ps->state]] == toketype_opval
	    && ps->val.opval)
	{
	    if (ps->compcv && (ps->compcv != PL_compcv)) {
		PL_compcv = ps->compcv;
		PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
		PL_comppad_name = PadlistNAMES(CvPADLIST(PL_compcv));
	    }
	    YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
	    op_free(ps->val.opval);
	}
	SvREFCNT_dec(ps->compcv);
	ps--;
    }

    Safefree(parser->stack);
}


/*----------.
| yyparse.  |
`----------*/

int
Perl_yyparse (pTHX_ int gramtype)
{
    dVAR;
    int yystate;
    int yyn;
    int yyresult;

    /* Lookahead token as an internal (translated) token number.  */
    int yytoken = 0;

    yy_parser *parser;	    /* the parser object */
    yy_stack_frame  *ps;   /* current parser stack frame */

#define YYPOPSTACK   parser->ps = --ps
#define YYPUSHSTACK  parser->ps = ++ps

    /* The variable used to return semantic value and location from the
	  action routines: ie $$.  */
    YYSTYPE yyval;

    YYDPRINTF ((Perl_debug_log, "Starting parse\n"));

    parser = PL_parser;

    ENTER;  /* force parser state cleanup/restoration before we return */
    SAVEPPTR(parser->yylval.pval);
    SAVEINT(parser->yychar);
    SAVEINT(parser->yyerrstatus);
    SAVEINT(parser->yylen);
    SAVEVPTR(parser->stack);
    SAVEVPTR(parser->stack_max1);
    SAVEVPTR(parser->ps);

    /* initialise state for this parse */
    parser->yychar = gramtype;
    parser->yyerrstatus = 0;
    parser->yylen = 0;
    Newx(parser->stack, YYINITDEPTH, yy_stack_frame);
    parser->stack_max1 = parser->stack + YYINITDEPTH - 1;
    ps = parser->ps = parser->stack;
    ps->state = 0;
    SAVEDESTRUCTOR_X(S_clear_yystack, parser);

/*------------------------------------------------------------.
| yynewstate -- Push a new state, which is found in yystate.  |
`------------------------------------------------------------*/
  yynewstate:

    while (1) {
    yystate = ps->state;

    YYDPRINTF ((Perl_debug_log, "Entering state %d\n", yystate));

    parser->yylen = 0;

    {
	/* grow the stack? We always leave 1 spare slot,
	 * in case of a '' -> 'foo' reduction.
         * Note that stack_max1 points to the (top-1)th allocated stack
         * element to make this check fast */

	if (ps >= parser->stack_max1) {
            Size_t pos = ps - parser->stack;
            Size_t newsize = 2 * (parser->stack_max1 + 2 - parser->stack);
	    /* this will croak on insufficient memory */
	    Renew(parser->stack, newsize, yy_stack_frame);
	    ps = parser->ps = parser->stack + pos;
	    parser->stack_max1 = parser->stack + newsize - 1;

	    YYDPRINTF((Perl_debug_log,
			    "parser stack size increased to %lu frames\n",
			    (unsigned long int)newsize));
	}
    }

/* Do appropriate processing given the current state.  */
/* Read a lookahead token if we need one and don't already have one.  */

    /* First try to decide what to do without reference to lookahead token.  */

    yyn = yypact[yystate];
    if (yyn == YYPACT_NINF)
	break;

    /* Not known => get a lookahead token if don't already have one.  */

    /* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol.  */
    if (parser->yychar == YYEMPTY) {
	YYDPRINTF ((Perl_debug_log, "Reading a token:\n"));
	parser->yychar = yylex();
    }

    if (parser->yychar <= YYEOF) {
	parser->yychar = yytoken = YYEOF;
	YYDPRINTF ((Perl_debug_log, "Now at end of input.\n"));
    }
    else {
        /* perly.tab is shipped based on an ASCII system, so need to index it
         * with characters translated to ASCII.  Although it's not designed for
         * this purpose, we can use NATIVE_TO_UNI here.  It returns its
         * argument on ASCII platforms, and on EBCDIC translates native to
         * ascii in the 0-255 range, leaving everything else unchanged.  This
         * jibes with yylex() returning some bare characters in that range, but
         * all tokens it returns are either 0, or above 255.  There could be a
         * problem if NULs weren't 0, or were ever returned as raw chars by
         * yylex() */
        yytoken = YYTRANSLATE (NATIVE_TO_UNI(parser->yychar));
	YYDSYMPRINTF ("Next token is", yytoken, &parser->yylval);
    }

    /* If the proper action on seeing token YYTOKEN is to reduce or to
     * detect an error, take that action.
     * Casting yyn to unsigned allows a >=0 test to be included as
     * part of the  <=YYLAST test for speed */
    yyn += yytoken;
    if ((unsigned int)yyn > YYLAST || yycheck[yyn] != yytoken)
	break;

    yyn = yytable[yyn];
    if (yyn <= 0) {
	if (yyn == 0 || yyn == YYTABLE_NINF)
	    goto yyerrlab;
	yyn = -yyn;
	goto yyreduce;
    }

    if (yyn == YYFINAL)
	YYACCEPT;

    /* Shift the lookahead token.  */
    YYDPRINTF ((Perl_debug_log, "Shifting token %s, ", yytname[yytoken]));

    /* Discard the token being shifted unless it is eof.  */
    if (parser->yychar != YYEOF)
	parser->yychar = YYEMPTY;

    YYPUSHSTACK;
    ps->state   = yyn;
    ps->val     = parser->yylval;
    ps->compcv  = (CV*)SvREFCNT_inc(PL_compcv);
    ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
    ps->name    = (const char *)(yytname[yytoken]);
#endif

    /* Count tokens shifted since error; after three, turn off error
	  status.  */
    if (parser->yyerrstatus)
	parser->yyerrstatus--;

    }


  /*-----------------------------------------------------------.
  | do the default action for the current state.  |
  `-----------------------------------------------------------*/
    yyn = yydefact[yystate];
    if (yyn == 0)
	goto yyerrlab;

  /*-----------------------------.
  | yyreduce -- Do a reduction.  |
  `-----------------------------*/
  yyreduce:
    /* yyn is the number of a rule to reduce with.  */
    parser->yylen = yyr2[yyn];

    /* If YYLEN is nonzero, implement the default value of the action:
      "$$ = $1".

      Otherwise, the following line sets YYVAL to garbage.
      This behavior is undocumented and Bison
      users should not rely upon it.  Assigning to YYVAL
      unconditionally makes the parser a bit smaller, and it avoids a
      GCC warning that YYVAL may be used uninitialized.  */
    yyval = ps[1-parser->yylen].val;

    YY_STACK_PRINT(parser);
    YY_REDUCE_PRINT (yyn);

    switch (yyn) {

/* contains all the rule actions; auto-generated from perly.y */
#include "perly.act"

    }

    {
	int i;
	for (i=0; i< parser->yylen; i++) {
	    SvREFCNT_dec(ps[-i].compcv);
	}
    }

    parser->ps = ps -= (parser->yylen-1);

    /* Now shift the result of the reduction.  Determine what state
	  that goes to, based on the state we popped back to and the rule
	  number reduced by.  */

    ps->val     = yyval;
    ps->compcv  = (CV*)SvREFCNT_inc(PL_compcv);
    ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
    ps->name    = (const char *)(yytname [yyr1[yyn]]);
#endif

    yyn = yyr1[yyn];

    yystate = yypgoto[yyn - YYNTOKENS] + ps[-1].state;
    if (0 <= yystate && yystate <= YYLAST && yycheck[yystate] == ps[-1].state)
	yystate = yytable[yystate];
    else
	yystate = yydefgoto[yyn - YYNTOKENS];
    ps->state = yystate;

    goto yynewstate;


  /*------------------------------------.
  | yyerrlab -- here on detecting error |
  `------------------------------------*/
  yyerrlab:
    /* If not already recovering from an error, report this error.  */
    if (!parser->yyerrstatus) {
	yyerror ("syntax error");
    }


    if (parser->yyerrstatus == 3) {
	/* If just tried and failed to reuse lookahead token after an
	      error, discard it.  */

	/* Return failure if at end of input.  */
	if (parser->yychar == YYEOF) {
	    /* Pop the error token.  */
	    SvREFCNT_dec(ps->compcv);
	    YYPOPSTACK;
	    /* Pop the rest of the stack.  */
	    while (ps > parser->stack) {
		YYDSYMPRINTF ("Error: popping", yystos[ps->state], &ps->val);
		LEAVE_SCOPE(ps->savestack_ix);
		if (yy_type_tab[yystos[ps->state]] == toketype_opval
			&& ps->val.opval)
		{
		    YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
		    if (ps->compcv != PL_compcv) {
			PL_compcv = ps->compcv;
			PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
		    }
		    op_free(ps->val.opval);
		}
		SvREFCNT_dec(ps->compcv);
		YYPOPSTACK;
	    }
	    YYABORT;
	}

	YYDSYMPRINTF ("Error: discarding", yytoken, &parser->yylval);
	parser->yychar = YYEMPTY;

    }

    /* Else will try to reuse lookahead token after shifting the error
	  token.  */
    goto yyerrlab1;


  /*----------------------------------------------------.
  | yyerrlab1 -- error raised explicitly by an action.  |
  `----------------------------------------------------*/
  yyerrlab1:
    parser->yyerrstatus = 3;	/* Each real token shifted decrements this.  */

    for (;;) {
	yyn = yypact[yystate];
	if (yyn != YYPACT_NINF) {
	    yyn += YYTERROR;
	    if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYTERROR) {
		yyn = yytable[yyn];
		if (0 < yyn)
		    break;
	    }
	}

	/* Pop the current state because it cannot handle the error token.  */
	if (ps == parser->stack)
	    YYABORT;

	YYDSYMPRINTF ("Error: popping", yystos[ps->state], &ps->val);
	LEAVE_SCOPE(ps->savestack_ix);
	if (yy_type_tab[yystos[ps->state]] == toketype_opval && ps->val.opval) {
	    YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
	    if (ps->compcv != PL_compcv) {
		PL_compcv = ps->compcv;
		PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
	    }
	    op_free(ps->val.opval);
	}
	SvREFCNT_dec(ps->compcv);
	YYPOPSTACK;
	yystate = ps->state;

	YY_STACK_PRINT(parser);
    }

    if (yyn == YYFINAL)
	YYACCEPT;

    YYDPRINTF ((Perl_debug_log, "Shifting error token, "));

    YYPUSHSTACK;
    ps->state   = yyn;
    ps->val     = parser->yylval;
    ps->compcv  = (CV*)SvREFCNT_inc(PL_compcv);
    ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
    ps->name    ="<err>";
#endif

    goto yynewstate;


  /*-------------------------------------.
  | yyacceptlab -- YYACCEPT comes here.  |
  `-------------------------------------*/
  yyacceptlab:
    yyresult = 0;
    for (ps=parser->ps; ps > parser->stack; ps--) {
	SvREFCNT_dec(ps->compcv);
    }
    parser->ps = parser->stack; /* disable cleanup */
    goto yyreturn;

  /*-----------------------------------.
  | yyabortlab -- YYABORT comes here.  |
  `-----------------------------------*/
  yyabortlab:
    yyresult = 1;
    goto yyreturn;

  yyreturn:
    LEAVE;	/* force parser stack cleanup before we return */
    return yyresult;
}

/*
 * ex: set ts=8 sts=4 sw=4 et:
 */