/* struct.c */                                                                                                                                                                                                      
#include <stdlib.h>                                                                                                                                                                                                 
#include <string.h>                                                                                                                                                                                                 
#include "struct.h"                                                                                                                                                                                                 
                                                                                                                                                                                                                    
void init_exp( struct exp* p )                                                                                                                                                                                      
{                                                                                                                                                                                                                   
    p->s = INIT;                                                                                                                                                                                                    
    p->depth = 0;                                                                                                                                                                                                   
}                                                                                                                                                                                                                   
int set_vexp( struct exp* p, char* s )                                                                                                                                                                              
{                                                                                                                                                                                                                   
    if ( p->s == L_NODE )                                                                                                                                                                                           
        return 2;                                                                                                                                                                                                   
    p->v.s = malloc( sizeof ( char ) * ( strlen( s ) + 1 ) );                                                                                                                                                       
    if ( p->v.s == NULL )                                                                                                                                                                                           
        return 1;                                                                                                                                                                                                   
    strcpy( p->v.s, s );                                                                                                                                                                                            
    p->s = B_NODE;                                                                                                                                                                                                  
    return 0;                                                                                                                                                                                                       
}                                                                                                                                                                                                                   
int add_node_exp( struct exp* p, struct exp* a )                                                                                                                                                                    
{                                                                                                                                                                                                                   
    if ( p->s == B_NODE )                                                                                                                                                                                           
        return 2;                                                                                                                                                                                                   
    p->v.n[p->depth++] = a;                                                                                                                                                                                         
    p->s = L_NODE;                                                                                                                                                                                                  
    return 0;                                                                                                                                                                                                       
}                                                                                                                                                                                                                   
/* ERROR PROBLEM IS HEAR */                                                                                                                                                                                         
void destroy_exp( struct exp* p )       /* warning: this recursively destroys the *ENTIRE* tree */                                                                                                                  
{                                                                                                                                                                                                                   
    if ( p->s == B_NODE )       /* we free the string if base */                                                                                                                                                    
        free( p->v.s );                                                                                                                                                                                             
    for ( ; p->depth > 0; p->depth-- )                                                                                                                                                                              
        destroy_exp( p->v.n[p->depth] ); /* we recursively destroy ALL nodes of the list */                                                                                                                         
    free( p );                           /* we destroy the node itself */                                                                                                                                           
}