cleanup

ffi/examples/read-table/schema.h

@@ -1,15 +1,16 @@
 #include "delta_kernel_ffi.h"
 
 /**
- * This module defines a very simple model of a schema, just used to be able to print the schema of
+ * This module defines a very simple model of a schema, used only to be able to print the schema of
  * a table. It consists of a "SchemaBuilder" which is our user data that gets passed into each visit_x
  * call. This simply keeps track of all the lists we are asked to allocate.
  *
- * Each list is a "SchemaItemList", which just tracks its length an an array of "SchemaItem"s.
+ * Each list is a "SchemaItemList", which tracks its length an an array of "SchemaItem"s.
  *
- * Each "SchemaItem" just has a name and a type, which are just strings. It can also have a list
- * which is its children. This is initially always NULL, but when visiting a struct, map, or array,
- * we point this at the list specified in the callback, which allows us to traverse the schema.
+ * Each "SchemaItem" has a name and a type, which are just strings. It can also have a list which is
+ * its children. This is initially always NULL, but when visiting a struct, map, or array, we point
+ * this at the list specified in the callback, which allows us to traverse the schema when printing
+ * it. Note that this points to one of the lists in the builder's set of lists and is not a copy.
  */
 
 // If you want the visitor to print out what it's being asked to do at each step, uncomment the
@@ -51,18 +52,19 @@ SchemaItem* add_to_list(SchemaItemList *list, char* name, char* type) {
 }
 
 // print out all items in a list, recursing into any children they may have
-void print_list(SchemaItemList *list, int indent, bool last) {
+void print_list(SchemaItemList *list, int indent, bool parent_on_last) {
   for (int i = 0; i < list->len; i++) {
+    bool is_last = i == list->len - 1;
     for (int j = 0; j <= indent; j++) {
       if (j == indent) {
-	if (i == list->len - 1) {
+	if (is_last) {
 	  printf("└");
 	} else {
 	  printf("├");
 	}
       } else {
-	if (last && j == indent - 1) {
-	  // don't print a dangling | for my last item
+	if (parent_on_last && j == indent - 1) {
+	  // don't print a dangling | on my parent's last item
 	  printf("   ");
 	} else {
 	  printf("│  ");
@@ -71,8 +73,7 @@ void print_list(SchemaItemList *list, int indent, bool last) {
     }
     printf("─ %s: %s\n", list->list[i].name, list->list[i].type);
     if (list->list[i].children) {
-      bool last = i == list->len - 1;
-      print_list(list->list[i].children, indent+1, last);
+      print_list(list->list[i].children, indent+1, is_last);
     }
   }
 }