/*
 * µscheme
 *
 * Copyright (C) 2015 Marc Alexander Lehmann <uscheme@schmorp.de>
 *                 do as you want with this, attribution appreciated.
 */

/* scheme-private.h */

#ifndef SCHEME_PRIVATE_H
#define SCHEME_PRIVATE_H

#include "scheme.h"

/*------------------ Ugly internals -----------------------------------*/

/*------------------ Of interest only to FFI users --------------------*/

# ifdef __cplusplus
extern "C"
{
# endif

enum scheme_port_kind
{
  port_free = 0,
  port_file = 1,
  port_string = 2,
  port_srfi6 = 4,
  port_input = 16,
  port_output = 32,
  port_saw_EOF = 64
};

typedef struct port
{
  unsigned char kind;
  int16_t unget;
  union
  {
    struct
    {
      int file;
      int closeit;
# if SHOW_ERROR_LINE
      int curr_line;
      char *filename;
# endif
    } stdio;
    struct
    {
      char *start;
      char *past_the_end;
      char *curr;
    } string;
  } rep;
} port;

/* cell structure */
struct cell
{
  union
  {
    struct
    {
      char *svalue;
      uint32_t length;
    } string;

    struct {
      struct cell **vvalue;
      uint32_t length;
    } vector;

    num number;

    port *port;

    foreign_func ff;

    struct
    {
      struct cell *car;
      struct cell *cdr;
    } cons;

  } object;

  uint8_t flag;
};

/* frequently accessed members are near the beginning, reducing codesize esp. on CISC */
struct scheme
{
  /* NIL is the most commonly accessed value */
  struct cell xNIL;           /* special cell representing empty cell */

  /* We use 4 registers. */
  pointer args;               /* register for arguments of function */
  pointer envir;              /* stack register for current environment */
  pointer code;               /* register for current code */
  pointer dump;               /* stack register for next evaluation */

  struct cell xT;             /* special cell representing #t */
  struct cell xF;             /* special cell representing #f */
  struct cell xEOF_OBJ;       /* special cell representing end-of-file object */
  struct cell xsink;          /* when mem. alloc. fails */

  /* arrays for segments */
#ifndef CELL_SEGSIZE
# define CELL_SEGSIZE    128   /* # of cells in one segment */
#endif
#ifndef CELL_NSEGMENT
# define CELL_NSEGMENT   10     /* # of segments for cells */
#endif
  char *alloc_seg[CELL_NSEGMENT];
  pointer cell_seg[CELL_NSEGMENT];
  int cell_segsize[CELL_NSEGMENT];
  int last_cell_seg;

  int interactive_repl;       /* are we in an interactive REPL? */

  pointer oblist;             /* pointer to symbol table */
  pointer global_env;         /* pointer to global environment */
  pointer c_nest;             /* stack for nested calls from C */

  /* global pointers to special symbols */
  pointer LAMBDA;             /* pointer to syntax lambda */
  pointer QUOTE;              /* pointer to syntax quote */

  pointer QQUOTE;             /* pointer to symbol quasiquote */
  pointer UNQUOTE;            /* pointer to symbol unquote */
  pointer UNQUOTESP;          /* pointer to symbol unquote-splicing */
  pointer FEED_TO;            /* => */
  pointer COLON_HOOK;         /* *colon-hook* */
  pointer ERROR_HOOK;         /* *error-hook* */
  pointer SHARP_HOOK;         /* *sharp-hook* */
  pointer COMPILE_HOOK;       /* *compile-hook* */

  pointer free_cell;          /* pointer to top of free cells */
  long fcells;                /* # of free cells */

  /* return code */
  int retcode;
  int tracing;

  pointer inport;
  pointer outport;
  pointer save_inport;
  pointer loadport;

#define MAXFIL 64
  port load_stack[MAXFIL];    /* Stack of open files for port -1 (LOADing) */
  int nesting_stack[MAXFIL];
  int file_i;
  int nesting;

  char gc_verbose;            /* if gc_verbose is not zero, print gc status */
  char no_memory;             /* Whether mem. alloc. has failed */

#define LINESIZE 1024
  char linebuff[LINESIZE];
#define STRBUFFSIZE 256
  char strbuff[STRBUFFSIZE];

  int tmpfp;
  int tok;
  int print_flag;
  pointer value;
  int op;

  void *ext_data;             /* For the benefit of foreign functions */
  long gensym_cnt;

  struct scheme_interface *vptr;
  struct dump_stack_frame *dump_base; /* pointer to base of allocated dump stack */
  int dump_size;                      /* number of frames allocated for dump stack */
};

/* operator code */
enum scheme_opcodes
{
#define OP_DEF(func,name,minarity,maxarity,argtest,op) op,
#include "opdefines.h"
#undef OP_DEF
  OP_MAXDEFINED
};

#define cons(a,b) xcons(SCHEME_A_ a,b,0)
#define immutable_cons(a,b) xcons(SCHEME_A_ a,b,1)

INTERFACE int is_string (pointer p);
INTERFACE char *string_value (pointer p);
INTERFACE int is_number (pointer p);
INTERFACE num nvalue (pointer p);
INTERFACE IVALUE ivalue (pointer p);
INTERFACE RVALUE rvalue (pointer p);
INTERFACE int is_integer (pointer p);
INTERFACE int is_real (pointer p);
INTERFACE int is_character (pointer p);
INTERFACE long charvalue (pointer p);
INTERFACE int is_vector (pointer p);

INTERFACE int is_port (pointer p);

INTERFACE int is_pair (pointer p);
INTERFACE pointer pair_car (pointer p);
INTERFACE pointer pair_cdr (pointer p);
INTERFACE void set_car (pointer p, pointer q);
INTERFACE void set_cdr (pointer p, pointer q);

INTERFACE int is_symbol (pointer p);
INTERFACE char *symname (pointer p);
INTERFACE int hasprop (pointer p);

INTERFACE int is_syntax (pointer p);
INTERFACE int is_proc (pointer p);
INTERFACE int is_foreign (pointer p);
INTERFACE char *syntaxname (pointer p);
INTERFACE int is_closure (pointer p);
#ifdef USE_MACRO
INTERFACE int is_macro (pointer p);
#endif
INTERFACE pointer closure_code (pointer p);
INTERFACE pointer closure_env (pointer p);

INTERFACE int is_continuation (pointer p);
INTERFACE int is_promise (pointer p);
INTERFACE int is_environment (pointer p);
INTERFACE int is_immutable (pointer p);
INTERFACE void setimmutable (pointer p);

#ifdef __cplusplus
}
#endif

#endif

/*
Local variables:
c-file-style: "k&r"
End:
*/