pic.y

早期freebsd实现

		}
	;

object_type:
	BOX
  		{ $$ = BOX_OBJECT; }
	| CIRCLE
		{ $$ = CIRCLE_OBJECT; }
	| ELLIPSE
		{ $$ = ELLIPSE_OBJECT; }
	| ARC
		{ $$ = ARC_OBJECT; }
	| LINE
		{ $$ = LINE_OBJECT; }
	| ARROW
		{ $$ = ARROW_OBJECT; }
	| SPLINE
		{ $$ = SPLINE_OBJECT; }
	| '[' ']'
		{ $$ = BLOCK_OBJECT; }
	| TEXT
		{ $$ = TEXT_OBJECT; }
	;

label_path:
 	'.' LABEL
		{
		  $$ = new path($2);
		}
	| label_path '.' LABEL
		{
		  $$ = $1;
		  $$->append($3);
		}
	;

relative_path:
	corner
		{
		  $$ = new path($1);
		}
	/* give this a lower precedence than LEFT and RIGHT so that
	   [A: box] with .A left == [A: box] with (.A left) */

  	| label_path %prec TEXT
		{
		  $$ = $1;
		}
	| label_path corner
		{
		  $$ = $1;
		  $$->append($2);
		}
	;

path:
	relative_path
		{
		  $$ = $1;
		}
	/* The rest of these rules are a compatibility sop. */
	| ORDINAL LAST object_type relative_path
		{
		  lex_warning("`%1%2 last %3' in `with' argument ignored",
			      $1, ordinal_postfix($1), object_type_name($3));
		  $$ = $4;
		}
	| LAST object_type relative_path
		{
		  lex_warning("`last %1' in `with' argument ignored",
			      object_type_name($2));
		  $$ = $3;
		}
	| ORDINAL object_type relative_path
		{
		  lex_warning("`%1%2 %3' in `with' argument ignored",
			      $1, ordinal_postfix($1), object_type_name($2));
		  $$ = $3;
		}
	| LABEL relative_path
		{
		  lex_warning("initial `%1' in `with' argument ignored", $1);
		  a_delete $1;
		  $$ = $2;
		}
	;

corner:
	DOT_N
		{ $$ = &object::north; }
	| DOT_E	
		{ $$ = &object::east; }
	| DOT_W
		{ $$ = &object::west; }
	| DOT_S
		{ $$ = &object::south; }
	| DOT_NE
		{ $$ = &object::north_east; }
	| DOT_SE
		{ $$ = &object:: south_east; }
	| DOT_NW
		{ $$ = &object::north_west; }
	| DOT_SW
		{ $$ = &object::south_west; }
	| DOT_C
		{ $$ = &object::center; }
	| DOT_START
		{ $$ = &object::start; }
	| DOT_END
		{ $$ = &object::end; }
  	| TOP
		{ $$ = &object::north; }
	| BOTTOM
		{ $$ = &object::south; }
	| LEFT
		{ $$ = &object::west; }
	| RIGHT
		{ $$ = &object::east; }
	| UPPER LEFT
		{ $$ = &object::north_west; }
	| LOWER LEFT
		{ $$ = &object::south_west; }
	| UPPER RIGHT
		{ $$ = &object::north_east; }
	| LOWER RIGHT
		{ $$ = &object::south_east; }
	| LEFT_CORNER
		{ $$ = &object::west; }
	| RIGHT_CORNER
		{ $$ = &object::east; }
	| UPPER LEFT_CORNER
		{ $$ = &object::north_west; }
	| LOWER LEFT_CORNER
		{ $$ = &object::south_west; }
	| UPPER RIGHT_CORNER
		{ $$ = &object::north_east; }
	| LOWER RIGHT_CORNER
		{ $$ = &object::south_east; }
	| CENTER
		{ $$ = &object::center; }
	| START
		{ $$ = &object::start; }
	| END
		{ $$ = &object::end; }
	;

expr:
	VARIABLE
		{
		  if (!lookup_variable($1, & $$)) {
		    lex_error("there is no variable `%1'", $1);
		    YYABORT;
		  }
		  a_delete $1;
		}
	| NUMBER
		{ $$ = $1; }
	| place DOT_X
  		{
		  if ($1.obj != 0)
		    $$ = $1.obj->origin().x;
		  else
		    $$ = $1.x;
		}			
	| place DOT_Y
		{
		  if ($1.obj != 0)
		    $$ = $1.obj->origin().y;
		  else
		    $$ = $1.y;
		}
	| place DOT_HT
		{
		  if ($1.obj != 0)
		    $$ = $1.obj->height();
		  else
		    $$ = 0.0;
		}
	| place DOT_WID
		{
		  if ($1.obj != 0)
		    $$ = $1.obj->width();
		  else
		    $$ = 0.0;
		}
	| place DOT_RAD
		{
		  if ($1.obj != 0)
		    $$ = $1.obj->radius();
		  else
		    $$ = 0.0;
		}
	| expr '+' expr
		{ $$ = $1 + $3; }
	| expr '-' expr
		{ $$ = $1 - $3; }
	| expr '*' expr
		{ $$ = $1 * $3; }
	| expr '/' expr
		{
		  if ($3 == 0.0) {
		    lex_error("division by zero");
		    YYABORT;
		  }
		  $$ = $1/$3;
		}
	| expr '%' expr
		{
		  if ($3 == 0.0) {
		    lex_error("modulus by zero");
		    YYABORT;
		  }
		  $$ = fmod($1, $3);
		}
	| expr '^' expr
		{
		  errno = 0;
		  $$ = pow($1, $3);
		  if (errno == EDOM) {
		    lex_error("arguments to `^' operator out of domain");
		    YYABORT;
		  }
		  if (errno == ERANGE) {
		    lex_error("result of `^' operator out of range");
		    YYABORT;
		  }
		}
	| '-' expr    %prec '!'
		{ $$ = -$2; }
	| '(' any_expr ')'
		{ $$ = $2; }
	| SIN '(' any_expr ')'
		{
		  errno = 0;
		  $$ = sin($3);
		  if (errno == ERANGE) {
		    lex_error("sin result out of range");
		    YYABORT;
		  }
		}
	| COS '(' any_expr ')'
		{
		  errno = 0;
		  $$ = cos($3);
		  if (errno == ERANGE) {
		    lex_error("cos result out of range");
		    YYABORT;
		  }
		}
	| ATAN2 '(' any_expr ',' any_expr ')'
		{
		  errno = 0;
		  $$ = atan2($3, $5);
		  if (errno == EDOM) {
		    lex_error("atan2 argument out of domain");
		    YYABORT;
		  }
		  if (errno == ERANGE) {
		    lex_error("atan2 result out of range");
		    YYABORT;
		  }
		}
	| LOG '(' any_expr ')'
		{
		  errno = 0;
		  $$ = log10($3);
		  if (errno == ERANGE) {
		    lex_error("log result out of range");
		    YYABORT;
		  }
		}
	| EXP '(' any_expr ')'
		{
		  errno = 0;
		  $$ = pow(10.0, $3);
		  if (errno == ERANGE) {
		    lex_error("exp result out of range");
		    YYABORT;
		  }
		}
	| SQRT '(' any_expr ')'
		{
		  errno = 0;
		  $$ = sqrt($3);
		  if (errno == EDOM) {
		    lex_error("sqrt argument out of domain");
		    YYABORT;
		  }
		}
	| K_MAX '(' any_expr ',' any_expr ')'
		{ $$ = $3 > $5 ? $3 : $5; }
	| K_MIN '(' any_expr ',' any_expr ')'
		{ $$ = $3 < $5 ? $3 : $5; }
	| INT '(' any_expr ')'
		{ $$ = floor($3); }
	| RAND '(' any_expr ')'
		{ $$ = 1.0 + floor(((rand()&0x7fff)/double(0x7fff))*$3); }
	| RAND '(' ')'
		{
		  /* return a random number in the range [0,1) */
		  /* portable, but not very random */
		  $$ = (rand() & 0x7fff) / double(0x8000);
		}
	| expr '<' expr
		{ $$ = ($1 < $3); }
	| expr LESSEQUAL expr
		{ $$ = ($1 <= $3); }
	| expr '>' expr
		{ $$ = ($1 > $3); }
	| expr GREATEREQUAL expr
		{ $$ = ($1 >= $3); }
	| expr EQUALEQUAL expr
		{ $$ = ($1 == $3); }
	| expr NOTEQUAL expr
		{ $$ = ($1 != $3); }
	| expr ANDAND expr
		{ $$ = ($1 != 0.0 && $3 != 0.0); }
	| expr OROR expr
		{ $$ = ($1 != 0.0 || $3 != 0.0); }
	| '!' expr
		{ $$ = ($2 == 0.0); }

	;

%%

/* bison defines const to be empty unless __STDC__ is defined, which it
isn't under cfront */

#ifdef const
#undef const
#endif

static struct {
  const char *name;
  double val;
  int scaled;		     // non-zero if val should be multiplied by scale
} defaults_table[] = {
  "arcrad", .25, 1,
  "arrowht", .1, 1,
  "arrowwid", .05, 1,
  "circlerad", .25, 1,
  "boxht", .5, 1,
  "boxwid", .75, 1,
  "boxrad", 0.0, 1,
  "dashwid", .05, 1,
  "ellipseht", .5, 1,
  "ellipsewid", .75, 1,
  "moveht", .5, 1,
  "movewid", .5, 1,
  "lineht", .5, 1,
  "linewid", .5, 1,
  "textht", 0.0, 1,
  "textwid", 0.0, 1,
  "scale", 1.0, 0,
  "linethick", -1.0, 0,		// in points
  "fillval", .5, 0,
  "arrowhead", 1.0, 0,
  "maxpswid", 8.5, 0,
  "maxpsht", 11.0, 0,
};

place *lookup_label(const char *label)
{
  saved_state *state = current_saved_state;
  PTABLE(place) *tbl = current_table;
  for (;;) {
    place *pl = tbl->lookup(label);
    if (pl)
      return pl;
    if (!state)
      return 0;
    tbl = state->tbl;
    state = state->prev;
  }
}

void define_label(const char *label, const place *pl)
{
  place *p = new place;
  *p = *pl;
  current_table->define(label, p);
}

int lookup_variable(const char *name, double *val)
{
  place *pl = lookup_label(name);
  if (pl) {
    *val = pl->x;
    return 1;
  }
  return 0;
}

void define_variable(const char *name, double val)
{
  place *p = new place;
  p->obj = 0;
  p->x = val;
  p->y = 0.0;
  current_table->define(name, p);
  if (strcmp(name, "scale") == 0) {
    // When the scale changes, reset all scaled pre-defined variables to
    // their default values.
    for (int i = 0; i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++) 
      if (defaults_table[i].scaled)
	define_variable(defaults_table[i].name, val*defaults_table[i].val);
  }
}

// called once only (not once per parse)

void parse_init()
{
  current_direction = RIGHT_DIRECTION;
  current_position.x = 0.0;
  current_position.y = 0.0;
  // This resets everything to its default value.
  reset_all();
}

void reset(const char *nm)
{
  for (int i = 0; i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
    if (strcmp(nm, defaults_table[i].name) == 0) {
      double val = defaults_table[i].val;
      if (defaults_table[i].scaled) {
	double scale;
	lookup_variable("scale", &scale);
	val *= scale;
      }
      define_variable(defaults_table[i].name, val);
      return;
    }
  lex_error("`%1' is not a predefined variable", nm);
}

void reset_all()
{
  // We only have to explicitly reset the pre-defined variables that
  // aren't scaled because `scale' is not scaled, and changing the
  // value of `scale' will reset all the pre-defined variables that
  // are scaled.
  for (int i = 0; i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
    if (!defaults_table[i].scaled)
      define_variable(defaults_table[i].name, defaults_table[i].val);
}

// called after each parse

void parse_cleanup()
{
  while (current_saved_state != 0) {
    delete current_table;
    current_table = current_saved_state->tbl;
    saved_state *tem = current_saved_state;
    current_saved_state = current_saved_state->prev;
    delete tem;
  }
  assert(current_table == &top_table);
  PTABLE_ITERATOR(place) iter(current_table);
  const char *key;
  place *pl;
  while (iter.next(&key, &pl))
    if (pl->obj != 0) {
      position pos = pl->obj->origin();
      pl->obj = 0;
      pl->x = pos.x;
      pl->y = pos.y;
    }
  while (olist.head != 0) {
    object *tem = olist.head;
    olist.head = olist.head->next;
    delete tem;
  }
  olist.tail = 0;
  current_direction = RIGHT_DIRECTION;
  current_position.x = 0.0;
  current_position.y = 0.0;
}

const char *ordinal_postfix(int n)
{
  if (n < 10 || n > 20)
    switch (n % 10) {
    case 1:
      return "st";
    case 2:
      return "nd";
    case 3:
      return "rd";
    }
  return "th";
}

const char *object_type_name(object_type type)
{
  switch (type) {
  case BOX_OBJECT:
    return "box";
  case CIRCLE_OBJECT:
    return "circle";
  case ELLIPSE_OBJECT:
    return "ellipse";
  case ARC_OBJECT:
    return "arc";
  case SPLINE_OBJECT:
    return "spline";
  case LINE_OBJECT:
    return "line";
  case ARROW_OBJECT:
    return "arrow";
  case MOVE_OBJECT:
    return "move";
  case TEXT_OBJECT:
    return "\"\"";
  case BLOCK_OBJECT:
    return "[]";
  case OTHER_OBJECT:
  case MARK_OBJECT:
  default:
    break;
  }
  return "object";
}

static char sprintf_buf[1024];

char *format_number(const char *form, double n)
{
  if (form == 0)
    form = "%g";
  else {
    // this is a fairly feeble attempt at validation of the format
    int nspecs = 0;
    for (const char *p = form; *p != '\0'; p++)
      if (*p == '%') {
	if (p[1] == '%')
	  p++;
	else
	  nspecs++;
      }
    if (nspecs > 1) {
      lex_error("bad format `%1'", form);
      return strsave(form);
    }
  }
  sprintf(sprintf_buf, form, n);
  return strsave(sprintf_buf);
}

char *do_sprintf(const char *form, const double *v, int nv)
{
  string result;
  int i = 0;
  string one_format;
  while (*form) {
    if (*form == '%') {
      one_format += *form++;
      for (; *form != '\0' && strchr("#-+ 0123456789.", *form) != 0; form++)
	one_format += *form;
      if (*form == '\0' || strchr("eEfgG%", *form) == 0) {
	lex_error("bad sprintf format");
	result += one_format;
	result += form;
	break;
      }
      if (*form == '%') {
	one_format += *form++;
	one_format += '\0';
	sprintf(sprintf_buf, one_format.contents());
      }
      else {
	if (i >= nv) {
	  lex_error("too few arguments to sprintf");
	  result += one_format;
	  result += form;
	  break;
	}
	one_format += *form++;
	one_format += '\0';
	sprintf(sprintf_buf, one_format.contents(), v[i++]);
      }
      one_format.clear();
      result += sprintf_buf;
    }
    else
      result += *form++;
  }
  result += '\0';
  return strsave(result.contents());
}