%{

#define YYDEBUG 1
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "prodrules.h"
#include "tree.h"
struct node *yyroot;
 %}
      
%union {
   struct node *np;
}

 /* YACC Declarations */
 %token <np> NUM '\n' '(' ')'
 %left <np>  '-' '+'
 %left <np>  '*' '/'
 %left <np>  NEG     /* negation--unary minus */
 %right <np>  '^'    /* exponentiation        */

 %type <np> input line exp mystart

 /* Grammar follows */
 %%
 mystart: input { yyroot = $1 ; printf("setting yyroot to %p\n", yyroot); } ;

 input:         input line { $$ = alcnary(INPUT, INPUT_R2, 2, $1, $2);
	      printf("setting input $$ to %p\n", $$);
	      }
              | { $$ = alcleaf( 0, ""); printf("$$ NULL\n"); }
      ;
      
 line:     '\n'  { $$ = alcnary(LINE, LINE_R1, 1, $1); }
           | exp '\n'  { $$ = alcnary(LINE, LINE_R2, 2, $1, $2); }
      ;
      
 exp:      NUM                     { $$ = $1; /* syntax tree vs. parse tree*/ }
              | exp '+' exp        { $$ = alcternary(EXP, EXP_R2, $1, $2, $3);}
              | exp '-' exp        { $$ = alcnary(EXP, EXP_R3, 3, $1, $2, $3);}
              | exp '*' exp        { $$ = alcnary(EXP, EXP_R4, 3, $1, $2, $3);}
              | exp '/' exp        { $$ = alcnary(EXP, EXP_R5, 3, $1, $2, $3);}
              | '-' exp  %prec NEG { $$ = alcnary(EXP, EXP_R6, 2, $1, $2);}
              | exp '^' exp        { $$ = alcnary(EXP, EXP_R7, 3, $1, $2, $3);}
              | '(' exp ')'        { $$ = alcnary(EXP, EXP_R8, 3, $1, $2, $3);}
      ;
 %%

#if 0

static char line[1024];

int advance(int n)
{
   int i;
   for (i=n; line[i]; i++) line[i-n] = line[i];
   line[i-n] = line[i];
}

int yylex()
{
   int tok, val;
   static int token_char;

   if (!strcmp(line, "")) {
      if (fgets(line, 1024, stdin) == NULL) { return -1; }
      }

   switch (line[0]) {
      case '\n': { advance(1); return '\n'; }
      case ' ': case '\t': { advance(1); return yylex(); }
      case '+': case '-': case '*': case '/': case '^': case '(': case ')':
	{
	int rv = line[0]; advance(1);
	return rv;
	}
      case '0': case '1':      case '2': case '3':      case '4': case '5':
      case '6': case '7':      case '8': case '9':      case '.': {
	val = atoi(line);

	yylval.np = (struct node *)malloc(sizeof(struct node));
	yylval.np->symbol = NUM;
	yylval.np->t.val = val;
	yylval.np->t.lexeme = strdup(line);
	/* unfinished: trim lexeme to stop at first char after number*/

	while (isdigit(line[0]) || (line[0]=='.')) advance(1);
	return NUM;
	}
      }
}
#endif

int yyerror(char *s)
{
   fprintf(stderr, "%s\n", s); fflush(stderr);
}

int main()
{
   int rv;
/*     yydebug = 1; */
     printf("---calling yyparse---\n");
     rv = yyparse();
     printf("---yyparse returned %d---\n", rv);
     printf("---calling treeprint---\n");
     treeprint(yyroot);
     printf("---done w/ treeprint---\n");
}