//	A tree has a name, and a (possibly empty) list of children

typedef struct _tree {
  char         * name;
  struct _list * children;  
} tree;

//	A list-node has:
//	- some data : a pointer to a tree
//	- a pointer to next node

typedef struct _node {
  struct _tree * tree;
  struct _node * next; 
} node;

//	A list holds:
//	- an int field: the current number of its nodes
//	- 2 pointers, to its first and last nodes respectively

typedef struct _list {
  int            nb;
  struct _node * first;
  struct _node * last;
} list;

//	Functions for building lists and elementary checking of them 

node * newNode(  tree * t );
list * newList(  );
void   addAChild( tree * t, tree * child );
void   printList( list *lp );

//	Functions for building trees, and simple checking of them

tree * newTree(  char * name );
void   addANode( list * lp, node * np );
tree * newLeaf( char * name );
tree * newTreeWithGivenChildren( char * name, list *children );
void   printTreeName( tree *tp );

//	Functions to operate on a tree in DFS Depth First Search order:
//	. when arriving at some node x, the function descends
//	  to each child y1, y2, ... in turn
//	. when at some son y, it does the same, etc...
//
//	DFSPrintTree just print the node names
//     	DFSVisitor() applies the f() function to each node
//	(could apply a print function as well, but may do more)

void   DFSPrintTree( tree * t, FILE * fp );
void   DFSVisitor( tree * t, void (*f)( ), int level );