61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/* The function
|
|
*
|
|
* char *Elk_Eval(char *expr);
|
|
*
|
|
* is similar to Tcl_Eval() in Tcl. It is called with a Scheme expression
|
|
* encoded as a C string and returns the result of evaluating the expression
|
|
* (as another C string), or a null pointer if an error has occured
|
|
* during evaluation.
|
|
*
|
|
* Elk_Eval() stores its result in a static buffer of fixed size; this
|
|
* can be improved easily by passing a buffer and a length as additional
|
|
* arguments.
|
|
*/
|
|
|
|
#include <string.h>
|
|
|
|
#include "scheme.h"
|
|
|
|
static Object in, out;
|
|
|
|
static char *String_Eval(expr) char *expr; {
|
|
Object str, res;
|
|
char *p;
|
|
GC_Node;
|
|
static char buf[1024];
|
|
|
|
str = Make_String(expr, strlen(expr));
|
|
PORT(in)->name = str;
|
|
PORT(in)->ptr = 0;
|
|
res = General_Read(in, 0);
|
|
GC_Link(res);
|
|
res = Eval(res);
|
|
(void)General_Print_Object(res, out, 1);
|
|
str = P_Get_Output_String(out);
|
|
p = Get_String(str);
|
|
if (strlen(p) > sizeof buf - 1)
|
|
p = "too long";
|
|
strcpy(buf, p);
|
|
GC_Unlink;
|
|
return buf;
|
|
}
|
|
|
|
char *Elk_Eval(expr) char *expr; {
|
|
char *s;
|
|
|
|
s = String_Eval("\
|
|
(call-with-current-continuation (lambda (c)\
|
|
(set! error-handler (lambda a (print a) (c #f))) #t))\
|
|
");
|
|
if (strcmp(s, "#f") == 0)
|
|
return 0;
|
|
return String_Eval(expr);
|
|
}
|
|
|
|
void elk_init_eval() {
|
|
in = P_Open_Input_String(Make_String("", 0));
|
|
Global_GC_Link(in);
|
|
out = P_Open_Output_String();
|
|
Global_GC_Link(out);
|
|
}
|