%{
#include "base.h"
#define S(tok) #tok

#include <stdlib.h>
int yyerror(char *s);
int yylex(void);
Node * parse_tree;
%}

%token NUMBER IDENTIFIER

%% /* Grammar rules and actions follow */

expr:	  expr '+' term
	| term
;

term:	  term '*' factor
	| factor
;

factor:	  '(' expr ')'
	| NUMBER
	| IDENTIFIER
;

%%

static void dump(Node * n, int level);

int main (void)
{
    /* yydebug = 1; */
    yyparse();
    dump(parse_tree, 0);
    return 0;
}

#include <stdio.h>

int yyerror(char *msg)  /* Called by yyparse on error */
{
    extern char *yytext;
    extern int yylineno;
    fprintf(stderr, "%d: %s at '%s'\n", yylineno, msg, yytext);
    return 0;
}

static Node * newnode(char const * s)
{
    Node * p = (Node *) malloc(sizeof(Node));
    p->child = p->sibling = NULL;
    strcpy(p->name, s);
    return p;
}

#include <stdarg.h>

Node * nn_nt(char const * name, ...)
{
    Node * p = newnode(name);
    Node * t;
    va_list ap;

    va_start(ap, name);
    p->child = va_arg(ap, Node *);
    t = p->child;
    while ((t->sibling=va_arg(ap, Node *)) != NULL) t = t->sibling;
    va_end(ap);
    return p;
}

Node * nn_ch(char const c)
{
    char s[2] = "a";
    s[0] = c;
    return newnode(s);
}

Node * nn_num(char const * val)
{
    return newnode(val);
}

Node * nn_id(char const * val)
{
    return newnode(val);
}

static void dump(Node * n, int level)
{
    printf("%*s%s\n", level*4, "", n->name);
    if (n->child)
	dump(n->child, level+1);
    if (n->sibling)
	dump(n->sibling, level);
}