bwbasic.h

这是一个简易的basic语言解释器, 可供我们学习和改进.

   };

/* Structure to define bwBASIC task: UNDER CONSTRUCTION */

#if PARACT
struct bwb_task
   {
   char progfile[ MAXARGSIZE ];		/* program file */
   int rescan;				/* program needs to be rescanned */
   int number;				/* current line number */
   struct bwb_line *bwb_l;		/* current line pointer */
   struct bwb_line bwb_start;		/* starting line marker */
   struct bwb_line bwb_end;		/* ending line marker */
   struct bwb_line *data_line;      	/* current line to read data */
   int data_pos;			/* position in data_line */
   struct bwb_variable var_start;	/* variable list start marker */
   struct bwb_variable var_end;		/* variable list end marker */
   struct bwb_function fnc_start;	/* function list start marker */
   struct bwb_function fnc_end;		/* function list end marker */
   struct fslte fslt_start;		/* function-sub-label lookup table start marker */
   struct fslte fslt_end;		/* function-sub-label lookup table end marker */
   int exsc;				/* EXEC stack counter */
   int expsc;				/* expression stack counter */
   int xtxtsc;				/* eXecute TeXT stack counter */
   struct exse excs[ EXECLEVELS ];	/* EXEC stack */
   struct exp_ese exps[ ESTACKSIZE ];	/* Expression stack */
   struct xtxtsl xtxts[ XTXTSTACKSIZE ];/* Execute Text stack */
   };

extern struct bwb_task *bwb_tasks[ TASKS ];	/* table of task pointers */

#else					/* not multi-tasking */

extern char progfile[ MAXARGSIZE ];	/* program file */
extern int rescan;			/* program needs to be rescanned */
extern int number;			/* current line number */
extern struct bwb_line *bwb_l;		/* current line pointer */
extern struct bwb_line bwb_start;	/* starting line marker */
extern struct bwb_line bwb_end;		/* ending line marker */
extern struct bwb_line *data_line;      /* current line to read data */
extern int data_pos;			/* position in data_line */
extern struct bwb_variable var_start;	/* variable list start marker */
extern struct bwb_variable var_end;	/* variable list end marker */
extern struct bwb_function fnc_start;	/* function list start marker */
extern struct bwb_function fnc_end;	/* function list end marker */
extern struct fslte fslt_start;		/* function-sub-label lookup table start marker */
extern struct fslte fslt_end;		/* function-sub-label lookup table end marker */
extern int exsc;			/* EXEC stack counter */
extern int expsc;			/* expression stack counter */
extern int xtxtsc;			/* eXecute TeXT stack counter */
extern struct exse *excs;		/* EXEC stack */
extern struct exp_ese *exps;		/* Expression stack */
extern struct xtxtsl *xtxts;		/* Execute Text stack */
#endif

extern int bwb_curtask;			/* current task */
extern struct bwb_variable *ed;         /* EDITOR$ variable */
extern struct bwb_variable *fi;         /* FILES$ variable */
extern struct bwb_variable *pr;         /* PROMPT$ variable */
extern struct bwb_variable *im;         /* IMPLEMENTATION$ variable */
extern struct bwb_variable *co;         /* COLORS variable */

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

	bwbasic.h	Part III: Global Data

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

extern char *bwb_ebuf;
extern int bwb_trace;
extern int dim_base;			/* set by OPTION BASE */
extern struct bwb_command bwb_cmdtable[ COMMANDS ];
extern FILE *errfdevice;                /* output device for error messages */
extern int err_line;			/* line in which error occurred */
extern int err_number;			/* number of last error */
extern char err_gosubl[ MAXVARNAMESIZE + 1 ]; /* line for error GOSUB */
extern char *err_table[ N_ERRORS ];	/* table of error messages */
extern int prn_col;
extern struct bwb_function bwb_prefuncs[ FUNCTIONS ];	/* table of predefined functions */

#if COMMON_CMDS
extern struct dev_element *dev_table;   /* table of devices */
#endif

/* Operator Structure and Table */

struct bwb_op
   {
   char symbol[ 8 ];                    /* BASIC symbol for the operator */
   int operation;                       /* internal code for the operator */
   int precedence;                      /* level of precedence, 0 = highest */
   };

extern struct bwb_op exp_ops[ N_OPERATORS ]; /* the table itself, filled in in bwb_tbl.c */

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

	bwbasic.h	Part IV: Function Prototypes

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

#if ANSI_C
extern void *CALLOC(size_t nelem, size_t elsize, char *str); /* JBV */
extern void FREE(void *ptr, char *str); /* JBV */
extern void bwb_init( int argc, char **argv );
extern int bwb_fload( FILE *file );
extern int bwb_ladd( char *buffer, int replace );
extern int bwb_findcmd( int argc, int a, struct bwb_line *l );
extern struct bwb_line *bwb_xtxtline( char *buffer );
extern void bwb_mainloop( void );
extern void bwb_execline( void );
extern int bwb_gets( char *buffer );
extern int bwb_error( char *message );
extern void break_handler( void );
extern void break_mes( int x );
extern struct bwb_line *bwb_null( struct bwb_line *l );
extern struct bwb_line *bwb_rem( struct bwb_line *l );
extern struct bwb_line *bwb_lerror( struct bwb_line *l );
extern struct bwb_line *bwb_run( struct bwb_line *l );
extern struct bwb_line *bwb_let( struct bwb_line *l );
extern struct bwb_line *bwb_load( struct bwb_line *l );
extern struct bwb_line *bwb_merge( struct bwb_line *l );
extern struct bwb_line *bwb_chain( struct bwb_line *l );
extern struct bwb_line *bwb_common( struct bwb_line *l );
extern struct bwb_line *bwb_xload( struct bwb_line *l );
extern struct bwb_line *bwb_new( struct bwb_line *l );
extern struct bwb_line *bwb_save( struct bwb_line *l );
extern struct bwb_line *bwb_list( struct bwb_line *l );
extern struct bwb_line *bwb_xlist( struct bwb_line *l, FILE *file );
extern struct bwb_line *bwb_go( struct bwb_line *l );
extern struct bwb_line *bwb_goto( struct bwb_line *l );
extern struct bwb_line *bwb_gosub( struct bwb_line *l );
extern struct bwb_line *bwb_return( struct bwb_line *l );
extern struct bwb_line *bwb_xend( struct bwb_line *l );
extern struct bwb_line *bwb_system( struct bwb_line *l );
extern struct bwb_line *bwb_tron( struct bwb_line *l );
extern struct bwb_line *bwb_troff( struct bwb_line *l );
extern struct bwb_line *bwb_randomize( struct bwb_line *l );
extern struct bwb_line *bwb_stop( struct bwb_line *l );
extern struct bwb_line *bwb_data( struct bwb_line *l );
extern struct bwb_line *bwb_read( struct bwb_line *l );
extern struct bwb_line *bwb_restore( struct bwb_line *l );
extern struct bwb_line *bwb_delete( struct bwb_line *l );
extern struct bwb_line *bwb_if( struct bwb_line *l );
extern struct bwb_line *bwb_else( struct bwb_line *l );
extern struct bwb_line *bwb_elseif( struct bwb_line *l );
extern struct bwb_line *bwb_select( struct bwb_line *l );
extern struct bwb_line *bwb_case( struct bwb_line *l );
extern struct bwb_line *bwb_endselect( struct bwb_line *l );
extern struct bwb_line *bwb_endif( struct bwb_line *l );
extern struct bwb_line *bwb_while( struct bwb_line *l );
extern struct bwb_line *bwb_wend( struct bwb_line *l );
extern struct bwb_line *bwb_for( struct bwb_line *l );
extern struct bwb_line *bwb_next( struct bwb_line *l );
extern struct bwb_line *bwb_dim( struct bwb_line *l );
extern struct bwb_line *bwb_option( struct bwb_line *l );
extern struct bwb_line *bwb_open( struct bwb_line *l );
extern struct bwb_line *bwb_close( struct bwb_line *l );
extern struct bwb_line *bwb_get( struct bwb_line *l );
extern struct bwb_line *bwb_put( struct bwb_line *l );
extern struct bwb_line *bwb_rmdir( struct bwb_line *l );
extern struct bwb_line *bwb_chdir( struct bwb_line *l );
extern struct bwb_line *bwb_mkdir( struct bwb_line *l );
extern struct bwb_line *bwb_kill( struct bwb_line *l );
extern struct bwb_line *bwb_name( struct bwb_line *l );
extern struct bwb_line *bwb_rset( struct bwb_line *l );
extern struct bwb_line *bwb_lset( struct bwb_line *l );
extern struct bwb_line *bwb_field( struct bwb_line *l );
extern struct bwb_line *bwb_on( struct bwb_line *l );
extern struct bwb_line *bwb_line( struct bwb_line *l );
extern struct bwb_line *bwb_ddbl( struct bwb_line *l );
extern struct bwb_line *bwb_dint( struct bwb_line *l );
extern struct bwb_line *bwb_dsng( struct bwb_line *l );
extern struct bwb_line *bwb_dstr( struct bwb_line *l );
extern struct bwb_line *bwb_mid( struct bwb_line *l );
extern struct bwb_line *bwb_clear( struct bwb_line *l );
extern struct bwb_line *bwb_erase( struct bwb_line *l );
extern struct bwb_line *bwb_swap( struct bwb_line *l );
extern struct bwb_line *bwb_environ( struct bwb_line *l );
extern struct bwb_line *bwb_width( struct bwb_line *l );
extern struct bwb_line *bwb_write( struct bwb_line *l );
extern struct bwb_line *bwb_edit( struct bwb_line *l );
extern struct bwb_line *bwb_files( struct bwb_line *l );
extern struct bwb_line *bwb_do( struct bwb_line *l );
extern struct bwb_line *bwb_doloop( struct bwb_line *l );
extern struct bwb_line *bwb_cls( struct bwb_line *l );
extern struct bwb_line *bwb_locate( struct bwb_line *l );
extern struct bwb_line *bwb_color( struct bwb_line *l );
extern struct bwb_line *bwb_do( struct bwb_line *l );
extern struct bwb_line *bwb_loop( struct bwb_line *l );
extern struct bwb_line *bwb_exit( struct bwb_line *l );
extern struct bwb_line *bwb_exitfor( struct bwb_line *l );
extern struct bwb_line *bwb_exitdo( struct bwb_line *l );

extern struct bwb_line *bwb_zline( struct bwb_line *l );

extern void bwb_incexec( void );
extern void bwb_decexec( void );
extern int bwb_setexec( struct bwb_line *l, int position, int code );
extern int bwb_getcnd( char *lb, char *lhs, char *rhs, char *op, int *n );
extern int bwb_getlhs( char *lb, char *lhs, int *n );
extern int bwb_getop( char *lb, char *op, int *n );
extern int bwb_getrhs( char *lb, char *rhs, int *n );
extern int bwb_evalcnd( char *lhs, char *rhs, char *op );
extern int bwb_isstr( char *b );
extern int eval_int( int l, int r, char *op );
extern int eval_sng( float l, float r, char *op );
extern int eval_dbl( double l, double r, char *op );
extern struct exp_ese *bwb_exp( char *expression, int assignment, int *position );
extern int exp_getvfname( char *source, char *destination );
extern int exp_operation( int entry_level );
extern int inc_esc( void );
extern int dec_esc( void );
extern int fnc_init( int task );
extern struct bwb_function *fnc_find( char *buffer );
extern struct bwb_line *bwb_def( struct bwb_line *l );
extern int bwb_getargs( char *buffer );
extern int bwb_stripcr( char *s );
extern int bwb_numseq( char *buffer, int *start, int *end );
extern int bwb_freeline( struct bwb_line *l );
extern struct bwb_line *bwb_print( struct bwb_line *l );
extern int bwb_xprint( struct bwb_line *l, FILE *f );
extern int bwb_eltype( char *l_buffer, int p );
extern int var_init( int task );
extern int fslt_init( int task );
extern int var_delcvars( void );
extern struct bwb_variable *var_new( char *name );
extern struct bwb_variable *var_islocal( char *buffer );
extern int bwb_strel( char *lb, char *sb, int *n );
extern struct bwb_variable *bwb_numel( char *lb, int *n );
extern int bwb_const( char *lb, char *sb, int *n );
extern int bwb_getvarname( char *lb, char *sb, int *n );
extern struct bwb_variable *var_find( char *buffer );
extern int bwb_isvar( char *buffer );
extern struct bwb_line *bwb_input( struct bwb_line *l );
extern int inp_adv( char *b, int *c );
extern int var_make( struct bwb_variable *v, int type );
extern bstring *var_getsval( struct bwb_variable *nvar );
extern bstring *var_findsval( struct bwb_variable *v, int *pp );
extern bstring *exp_getsval( struct exp_ese *e );
extern int dim_getparams( char *buffer, int *pos, int *n_params, int **pp );
extern int adv_element( char *buffer, int *pos, char *element );
extern int adv_ws( char *buffer, int *pos );
#if MULTISEG_LINES
extern int adv_eos( char *buffer, int *pos );
#endif
extern int line_start( char *buffer, int *pos, int *lnpos, int *lnum,
   int *cmdpos, int *cmdnum, int *startpos );
extern int is_cmd( char *buffer, int *cmdnum );
extern int is_let( char *buffer, int *cmdnum );
extern int is_eol( char *buffer, int *position );
extern int is_numconst( char *buffer );
extern int is_label( char *buffer );
extern struct bwb_line * find_label( char *buffer );
extern struct bwb_line *find_loop( struct bwb_line *l );
extern int int_qmdstr( char *buffer_a, char *buffer_b );
extern struct bwb_line * cnd_xpline( struct bwb_line *l, char *buffer );
extern int scan_element( char *buffer, int *pos, char *element );

extern int prn_precision( struct bwb_variable *v );
extern int * prn_getcol( FILE *f );
extern int prn_getwidth( FILE *f );
extern int prn_xprintf( FILE *f, char *buffer );
extern int prn_xxprintf( FILE *f, char *buffer ); /* JBV */
extern int bwb_strtoupper( char *buffer );
extern int getcmdnum( char *cmdstr );

extern int str_btoc( char *buffer, bstring *s );
extern int str_btob( bstring *d, bstring *s );
extern int str_ctob( bstring *s, char *buffer );
extern int str_cmp( bstring *s, bstring *t );
extern char * str_cat( bstring *s, bstring *t );
extern int exp_findop( char *expression );
extern int exp_isop( char *expression );
extern int exp_isfn( char *expression );
extern int exp_isufn( char *expression );
extern int exp_isnc( char *expression );
extern int exp_isvn( char *expression );
extern int exp_iscmd( char *expression );
extern int exp_paren( char *expression );
extern int exp_strconst( char *expression );
extern int exp_numconst( char *expression );
extern int exp_function( char *expression );
extern int exp_ufnc( char *expression );
extern int exp_variable( char *expression );
extern int exp_validarg( char *expression );
extern int ln_asbuf( struct bwb_line *l, char *s );
extern int xputc( FILE *f, char c );
extern int bwx_signon( void );
extern int bwx_message( char *m );
extern int bwx_putc( char c );
extern int bwx_errmes( char *m );
extern int bwx_input( char *prompt, char *buffer );
extern void bwx_terminate( void );

#if COMMAND_SHELL
extern int bwx_shell( struct bwb_line *l );
#endif

int bwb_scan( void );
struct bwb_line *bwb_call( struct bwb_line *l );
struct bwb_line *bwb_sub( struct bwb_line *l );
struct bwb_line *bwb_endsub( struct bwb_line *l );
struct bwb_line *bwb_endfnc( struct bwb_line *l );
struct bwb_line *bwb_function( struct bwb_line *l );

extern bnumber var_getnval( struct bwb_variable *nvar );
extern bnumber *var_findnval( struct bwb_variable *v, int *pp );
extern bnumber exp_getnval( struct exp_ese *e );
extern bnumber *exp_findnval( struct exp_ese *e );

#if PARACT
extern int bwb_newtask( int task_requested );
#endif

#if INTERACTIVE
extern int bwb_interact( void );
#endif

#if DEBUG
extern int bwb_debug( char *message );
extern struct bwb_line *bwb_cmds( struct bwb_line *l );
extern struct bwb_line *bwb_vars( struct bwb_line *l );
extern struct bwb_line *bwb_fncs( struct bwb_line *l );
#endif

#ifdef ALLOW_RENUM
extern struct bwb_line *bwb_renum( struct bwb_line *l );
#endif

#if UNIX_CMDS
#if !HAVE_UNISTD /* Not needed if one has <unistd.h> (JBV) */
extern int rmdir( char *path );
extern int chdir( char *path );
#endif
#if !HAVE_SYSSTAT /* Not needed if one has <sys/stat.h> (JBV) */
#if MKDIR_ONE_ARG
extern int mkdir( char *path );
#else
extern int mkdir( char *path, unsigned short permissions );
#endif /* JBV */
#endif
#endif

/* declarations of function commands */

extern struct bwb_variable *fnc_null( int argc, struct bwb_variable *argv, int unique_id );
#if COMPRESS_FUNCS
extern struct bwb_variable *fnc_core( int argc, struct bwb_variable *argv, int unique_id );
#else
extern struct bwb_variable *fnc_abs( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_atn( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_cos( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_log( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_sin( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_sqr( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_sgn( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_int( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_rnd( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_exp( int argc, struct bwb_variable *argv, int unique_id );
extern struct bwb_variable *fnc_tan( int argc, struct bwb_variable *argv, int unique_id );