/* This is a simple demo program for the S-Lang interpreter.  It would 
 * take very little work to make this demo *really* useful.
 */

#include <math.h>
#include <stdio.h>

#ifndef NO_STDLIB_H
#include <stdlib.h>
#endif

#include "slang.h"

int Read_Only_Array [100];
int Writable_Array [100];
FLOAT XXX;

void help()
{
   puts("ALL statements MUST be terminated with a ';' character, e.g., quit();\n");
   puts("Available functions:");
   puts("  cos, sin, tan, atan, acos, asin, exp, log, sqrt, fabs, log10, pow, PI, E");
   puts("  print -- prints string, e.g. print(\"hello world!\\n\");");
   puts("\nas well as intrinsic S-Lang functions.");
   puts("See S-Lang language documentation for further details.\n");
   SLang_run_hooks ("calc_help", NULL, NULL);
}      

/* The following three functions will be callable from the interpreter */
void quit_calc()
{
   SLang_reset_tty ();
   exit(0);
}


void print(char *s)
{
   fputs(s, stdout);
}

void error(char *s)
{
   fprintf(stderr, "%s\n", s);
   SLang_Error = 1;
}

/* Now here is a table that provides the link between the above functions and
   the S-Lang interpreter */
SLang_Name_Type Calc_Intrinsics[] =
{
   MAKE_INTRINSIC(".print", print, VOID_TYPE, 1),
   MAKE_INTRINSIC(".quit", quit_calc, VOID_TYPE, 0),
   MAKE_INTRINSIC(".help", help, VOID_TYPE, 0),
   MAKE_INTRINSIC(".error", error, VOID_TYPE, 1),
   MAKE_VARIABLE(".XXX", &XXX, FLOAT_TYPE, 0),
   SLANG_END_TABLE
};

#ifdef unix
#define EOF_CHAR 4
#else
#define EOF_CHAR 26
#endif

int test (int argc, SLcmd_Cmd_Table_Type *table)
{
   fprintf (stdout, "f = %s, argc = %d\n", table->string_args[0], argc);
   switch (argc)
     {
      default:  fprintf(stdout, "Argc out of range!\n");
	return -1;
      case 4:
	fprintf (stdout, "arg[%d] = %f\n", argc, table->float_args[argc - 1]);
	argc--;
      case 3:
	fprintf (stdout, "arg[%d] = %d\n", argc, table->int_args[argc - 1]);
	argc--;
	
      case 2:
	fprintf (stdout, "arg[%d] = %s\n", argc, table->string_args[argc - 1]);
	argc--;
	
      case 1:
	break;
     }
   return 0;
}

SLcmd_Cmd_Type Cmd_Table[] = 
{
   {test, "test0", ""},
   {test, "test1", "S"},
   {test, "test2", "SI"},
   {test, "test3", "SIF"},
   {NULL, "", ""}
};

SLcmd_Cmd_Table_Type The_Cmd_Table;

static SLang_RLine_Info_Type *init_readline (void);
int main (int argc, char **argv)
{
   SLang_RLine_Info_Type *rli;
   int nread;
   char *status;
   
   if (!init_SLang() 		       /* basic interpreter functions */
       || !init_SLmath() 	       /* sin, cos, etc... */
#ifdef unix
       || !init_SLunix()
#endif
       || !init_SLfiles()	       /* file i/o */
       /* || !init_SLmatrix()	*/       /* matrix manipluation */
       || !SLang_add_table(Calc_Intrinsics, "Calc"))   /* calc specifics */
     {
	fprintf(stderr, "Unable to initialize S-Lang.\n");
	exit(1);
     }

   if ((-1 == SLang_add_array ("Read_only_array", (long *) Read_Only_Array,
			       1, 100, 0, 0, 'i', LANG_RVARIABLE))
       || (-1 == SLang_add_array ("Writable_array", (long *) Writable_Array,
				  1, 100, 0, 0, 'i', LANG_IVARIABLE)))
     {
	fprintf(stderr, "Failed to add arrays\n");
	exit (-1);
     }
       
   rli = init_readline ();
   if (SLang_init_tty (7, 0, 1))
     {
	fprintf(stderr, "Unable to initialize tty.");
	exit (-1);
     }
   
   SLang_set_abort_signal (NULL);
   
   SLang_Traceback = 1;
   SLang_load_file("calc.sl");
   
   while (--argc && !SLang_Error)
     {
	argv++;
	SLang_load_file (*argv);
     }

   
   fputs("Type 'help();' for help and a list of available functions.\n", stdout);
   fputs("Note also that statements end in a ';'\n", stdout);
   fputs("\nIt is also important to note that most binary operators +, -, *, /,\n", stdout);
   fputs("as well as the '=' sign must be surrounded by spaces!\n", stdout);
   
   The_Cmd_Table.table = Cmd_Table;
   
   while(1)
     {
	if (SLang_Error) SLang_restart(1);
	SLKeyBoard_Quit = SLang_Error = 0;
	nread = SLang_read_line (rli);
	putc('\n', stdout);
	if (nread > 0)
	  {
	     if ((nread == 1) && (*rli->buf == EOF_CHAR)) break;
	     if (*rli->buf == '@')
	       {
		  status = NULL;
		  
		  (void) SLcmd_execute_string ((char *) rli->buf + 1, &The_Cmd_Table);
	       }
	     else status = SLang_load_string ((char *) rli->buf);
	     if (SLang_Error == 0) 
	       {
		  SLang_rline_save_line (rli);
		  *rli->buf = 0;
	       }
	     else 
	       {
		  if (status == NULL) rli->point = 0;
		  else rli->point = (int) (status - (char *) rli->buf);
	       }
	  }
     }
   SLang_reset_tty ();
   return (SLang_Error);
}

static SLang_RLine_Info_Type  *init_readline (void)
{
   SLang_RLine_Info_Type *rli;
   unsigned char *buf = NULL;
   
   if ((NULL == (rli = (SLang_RLine_Info_Type *) MALLOC (sizeof(SLang_RLine_Info_Type))))
       || (NULL == (buf = (unsigned char *) MALLOC (256))))
     {
	fprintf(stderr, "malloc error.\n");
	exit(-1);
     }
   
   MEMSET ((char *) rli, 0, sizeof (SLang_RLine_Info_Type));
   rli->buf = buf;
   rli->buf_len = 255;
   rli->tab = 8;
   rli->edit_width = 79;
   rli->dhscroll = 20;
   rli->prompt = "Calc> ";
   rli->getkey = SLang_getkey;
#if !defined(__GO32__) && !defined(msdos)
   rli->flags = SLRL_USE_ANSI;
#endif
   SLang_init_readline (rli);
   return rli;
}