Add variable "csnumprec" to allow setting the precision of vectors

and variables as arguments to functions listet in manual chapter 17.5.
Default is 6, as has been standard up to now.

src/frontend/variable.c

@@ -39,6 +39,7 @@ wordlist *cp_varwl(struct variable *var)
     wordlist *wl = NULL, *w, *wx = NULL;
     char *buf;
     struct variable *vt;
+    int csnump = 0;
 
     switch (var->va_type) {
     case CP_BOOL:
@@ -49,8 +50,10 @@ wordlist *cp_varwl(struct variable *var)
         buf = tprintf("%d", var->va_num);
         break;
     case CP_REAL:
-        /* This is a case where printnum isn't too good... */
-        buf = tprintf("%G", var->va_real);
+        if (cp_getvar("csnumprec", CP_NUM, &csnump, 0) && csnump > 0)
+            buf = tprintf("%.*g",csnump, var->va_real); /* csnumprec is set */
+        else
+            buf = tprintf("%G", var->va_real); /* standard behavior */
         break;
     case CP_STRING:
         buf = copy(var->va_string);