Finish ps2

exercises/02/vslc/src/parser.y

@@ -13,6 +13,7 @@
 %left '*' '/'
 %nonassoc UMINUS
 %right '~'
+%expect 1
 
 %nonassoc IF THEN
 %nonassoc ELSE

exercises/02/vslc/src/tree.c

@@ -5,6 +5,50 @@ static void node_finalize ( node_t *discard );
 static void destroy_subtree ( node_t *discard );
 
 
+typedef struct stem_t *stem;
+struct stem_t { const char *str; stem next; };
+static void
+tree_print(node_t* root, stem head) 
+{
+    static const char *sdown = "  │", *slast = "  └", *snone = "   ";
+	struct stem_t col = {0, 0}, *tail;
+
+    for (tail = head; tail; tail = tail->next) {
+        if (!tail->next) {
+            if (!strcmp(sdown, tail->str))
+                printf("  ├");
+            else 
+                printf("%s", tail->str);
+            break;
+        }
+        printf("%s", tail->str);
+	}
+    
+    printf("──%s", node_string[root->type] );
+    if ( root->type == IDENTIFIER_DATA ||
+         root->type == STRING_DATA ||
+         root->type == EXPRESSION ) 
+        printf("(%s)", (char *) root->data);
+    else if (root->type == NUMBER_DATA)
+        printf ( "(%ld)", *((int64_t *)root->data) );
+    putchar ( '\n' );
+ 
+	if (!root->n_children) return;
+ 
+	if (tail && tail->str == slast)
+		tail->str = snone;
+ 
+	if (!tail)	tail = head = &col;
+	else		tail->next = &col;
+
+    for ( int64_t i=0; i < root->n_children; i++ ) {
+        col.str = root->n_children - i - 1 ? sdown : slast;
+        tree_print(root->children[i], head);
+    }
+	tail->next = 0;
+}
+
+
 /* External interface */
 void
 destroy_syntax_tree ( void )
@@ -16,7 +60,8 @@ destroy_syntax_tree ( void )
 void
 print_syntax_tree ( void )
 {
-    node_print ( root, 0 );
+    //node_print ( root, 0 );
+    tree_print(root, 0);
 }