/*    parser.h
 *
 *    Copyright (c) 2006, 2007, 2009, 2010, 2011 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.
 * 
 * This file defines the layout of the parser object used by the parser
 * and lexer (perly.c, toke.c).
 */

#define YYEMPTY		(-2)

typedef struct {
    YYSTYPE val;    /* semantic value */
    short   state;
    I32     savestack_ix;	/* size of savestack at this state */
    CV	    *compcv; /* value of PL_compcv when this value was created */
#ifdef DEBUGGING
    const char  *name; /* token/rule name for -Dpv */
#endif
} yy_stack_frame;

/* Fields that need to be shared with (i.e., visible to) inner lex-
   ing scopes. */
typedef struct yy_lexshared {
    struct yy_lexshared	*ls_prev;
    SV			*ls_linestr;	/* mirrors PL_parser->linestr */
    char		*ls_bufptr;	/* mirrors PL_parser->bufptr */
    char		*re_eval_start;	/* start of "(?{..." text */
    SV			*re_eval_str;	/* "(?{...})" text */
} LEXSHARED;

typedef struct yy_parser {

    /* parser state */

    struct yy_parser *old_parser; /* previous value of PL_parser */
    YYSTYPE	    yylval;	/* value of lookahead symbol, set by yylex() */
    int		    yychar;	/* The lookahead symbol.  */

    /* Number of tokens to shift before error messages enabled.  */
    int		    yyerrstatus;

    int		    yylen;	/* length of active reduction */
    yy_stack_frame  *stack;	/* base of stack */
    yy_stack_frame  *stack_max1;/* (top-1)th element of allocated stack */
    yy_stack_frame  *ps;	/* current stack frame */

    /* lexer state */

    I32		lex_brackets;	/* square and curly bracket count */
    I32		lex_casemods;	/* casemod count */
    char	*lex_brackstack;/* what kind of brackets to pop */
    char	*lex_casestack;	/* what kind of case mods in effect */
    U8		lex_defer;	/* state after determined token */
    U8		lex_dojoin;	/* doing an array interpolation
				   1 = @{...}  2 = ->@ */
    U8		expect;		/* how to interpret ambiguous tokens */
    bool	preambled;
    I32		lex_formbrack;	/* bracket count at outer format level */
    OP		*lex_inpat;	/* in pattern $) and $| are special */
    OP		*lex_op;	/* extra info to pass back on op */
    SV		*lex_repl;	/* runtime replacement from s/// */
    U16		lex_inwhat;	/* what kind of quoting are we in */
    OPCODE	last_lop_op;	/* last named list or unary operator */
    I32		lex_starts;	/* how many interps done on level */
    SV		*lex_stuff;	/* runtime pattern from m// or s/// */
    I32		multi_start;	/* 1st line of multi-line string */
    I32		multi_end;	/* last line of multi-line string */
    UV		multi_open;	/* delimiter of said string */
    UV		multi_close;	/* delimiter of said string */
    bool        lex_re_reparsing; /* we're doing G_RE_REPARSING */
    U8		lex_super_state;/* lexer state to save */
    U16		lex_sub_inwhat;	/* "lex_inwhat" to use in sublex_push */
    I32		lex_allbrackets;/* (), [], {}, ?: bracket count */
    OP		*lex_sub_op;	/* current op in y/// or pattern */
    SV		*lex_sub_repl;	/* repl of s/// used in sublex_push */
    LEXSHARED	*lex_shared;
    SV		*linestr;	/* current chunk of src text */
    char	*bufptr;	/* carries the cursor (current parsing
				   position) from one invocation of yylex
				   to the next */
    char	*oldbufptr;	/* in yylex, beginning of current token */
    char	*oldoldbufptr;	/* in yylex, beginning of previous token */
    char	*bufend;	
    char	*linestart;	/* beginning of most recently read line */
    char	*last_uni;	/* position of last named-unary op */
    char	*last_lop;	/* position of last list operator */
    /* copline is used to pass a specific line number to newSTATEOP.  It
       is a one-time line number, as newSTATEOP invalidates it (sets it to
       NOLINE) after using it.  The purpose of this is to report line num-
       bers in multiline constructs using the number of the first line. */
    line_t	copline;
    U16		in_my;		/* we're compiling a "my"/"our" declaration */
    U8		lex_state;	/* next token is determined */
    U8		error_count;	/* how many compile errors so far, max 10 */
    HV		*in_my_stash;	/* declared class of this "my" declaration */
    PerlIO	*rsfp;		/* current source file pointer */
    AV		*rsfp_filters;	/* holds chain of active source filters */

    YYSTYPE	nextval[5];	/* value of next token, if any */
    I32		nexttype[5];	/* type of next token */
    U8		nexttoke;
    U8		form_lex_state;	/* remember lex_state when parsing fmt */
    U8		lex_fakeeof;	/* precedence at which to fake EOF */
    U8		lex_flags;
    COP		*saved_curcop;	/* the previous PL_curcop */
    char	tokenbuf[256];
    line_t	herelines;	/* number of lines in here-doc */
    line_t	preambling;	/* line # when processing $ENV{PERL5DB} */

    /* these are valid while parsing a subroutine signature */
    IV          sig_elems;      /* number of signature elements seen so far */
    IV          sig_optelems;   /* number of optional signature elems seen */
    char        sig_slurpy;     /* the sigil of the slurpy var (or null) */

    bool        recheck_utf8_validity;

    PERL_BITFIELD16	in_pod:1;      /* lexer is within a =pod section */
    PERL_BITFIELD16	filtered:1;    /* source filters in evalbytes */
    PERL_BITFIELD16	saw_infix_sigil:1; /* saw & or * or % operator */
    PERL_BITFIELD16	parsed_sub:1;  /* last thing parsed was a sub */

    bool        sub_no_recover; /* can't recover from a sublex error */
    U8		sub_error_count; /* the number of errors before sublexing */
} yy_parser;

/* flags for lexer API */
#define LEX_STUFF_UTF8		0x00000001
#define LEX_KEEP_PREVIOUS	0x00000002

#ifdef PERL_CORE
# define LEX_START_SAME_FILTER	0x00000001
# define LEX_IGNORE_UTF8_HINTS	0x00000002
# define LEX_EVALBYTES		0x00000004
# define LEX_START_COPIED	0x00000008
# define LEX_DONT_CLOSE_RSFP	0x00000010
# define LEX_START_FLAGS \
	(LEX_START_SAME_FILTER|LEX_START_COPIED \
	|LEX_IGNORE_UTF8_HINTS|LEX_EVALBYTES|LEX_DONT_CLOSE_RSFP)
#endif

/* flags for parser API */
#define PARSE_OPTIONAL          0x00000001

/* values for lex_fakeeof */
enum {
    LEX_FAKEEOF_NEVER,      /* don't fake EOF */
    LEX_FAKEEOF_CLOSING,    /* fake EOF at unmatched closing punctuation */
    LEX_FAKEEOF_NONEXPR,    /* ... and at token that can't be in expression */
    LEX_FAKEEOF_LOWLOGIC,   /* ... and at low-precedence logic operator */
    LEX_FAKEEOF_COMMA,      /* ... and at comma */
    LEX_FAKEEOF_ASSIGN,     /* ... and at assignment operator */
    LEX_FAKEEOF_IFELSE,     /* ... and at ?: operator */
    LEX_FAKEEOF_RANGE,      /* ... and at range operator */
    LEX_FAKEEOF_LOGIC,      /* ... and at logic operator */
    LEX_FAKEEOF_BITWISE,    /* ... and at bitwise operator */
    LEX_FAKEEOF_COMPARE,    /* ... and at comparison operator */
    LEX_FAKEEOF_MAX
};

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