#include <stdio.h>
#include <stdlib.h>

typedef struct _Node  Node;
typedef struct _Block Block;
typedef struct _List  List;

struct _Node {  // (could use an union to store the first 2 fields)
  char  * name; // IF a "simple node": it has just a name, no block ptr
  Block * bptr; // OTHERWISE: has no name, but a pointer to a (named) block
  Node  * next;
};

struct _Block {
  char * name;  // the name common to the opening and closing tags
  int    level;	// store the level in the tree; mostly for tracing purpose
  List * list;  // the content of the block
};

struct _List {
  Node * first;
  Node * last;
};

List * newList( ) {
  List * list = malloc(sizeof(List));
  list->first = list->last = 0;
  return list;
}

Node * newSimpleNode( char * name ) {
  Node *nptr = (Node *)malloc(sizeof(Node));
  nptr->name = name;
  nptr->bptr = 0;	// no block pointer
  nptr->next = 0;
  return nptr;
}

Node * newNodeWithABlock( Block * bptr ) {
  Node *nptr = (Node *)malloc(sizeof(Node));
  nptr->bptr = bptr;
  nptr->name = 0;	// no name
  nptr->next = 0;
  return nptr;
}

Block * newBlock( char * nm, List * lptr , int level ) {
  Block * bptr = (Block *) malloc(sizeof(Block));
  bptr->name  = nm;
  bptr->level = level;
  bptr->list  = lptr;
  return bptr;
}

void appendNodeToList( Node * nptr, List * lptr ) {

  // If appended node is simple, it has a name;
  // otherwise it points at a block which has one
  char * s = nptr->name;
  if( s==0 ) s = nptr->bptr->name;

  if ( lptr->first == 0 ) {
    lptr->first = lptr->last = nptr;
  } else {
    lptr->last->next = nptr;
    lptr->last = nptr;
  }
}

void blockList( Block * b ) {

  Node * nd;
  printf("Bloc %s l=%d\n",b->name,b->level); fflush(stdout);
  nd = b->list->first;
  while( nd != 0 ) {
    if( nd->name != 0 ) { printf("%s ",nd->name); fflush(stdout); }
    else                { blockList(nd->bptr);                    }
    nd = nd->next;
  }
}

/*
//	Exemple construisant un arbre simple
//	A
//	|_______B
//		|_______C
//		/_______D

main( ) {

  Block * bp0, * bp1;
  List  * lp0 = newList();
  List  * lp1 = newList();
  appendNodeToList( newSimpleNode("C"), lp1 );
  appendNodeToList( newSimpleNode("D"), lp1 );
  bp1 = newBlock( "B", lp1, 1);
  appendNodeToList( newNodeWithABlock( bp1 ), lp0 );
  bp0 = newBlock( "A", lp0, 0 );
  printf("\n");
  blockList( bp0 );
  printf("\n");

}
*/