int main() {
VC vc = vc_createValidityChecker(NULL);
/* Prove that for integers x and y:
* x > 0 AND y > 0 => 2x + y >= 3 */
Type integer = vc_intType(vc);
Expr x = vc_varExpr(vc, "x", integer);
Expr y = vc_varExpr(vc, "y", integer);
Expr zero = vc_ratExpr(vc, 0, 1);
Expr x_positive = vc_gtExpr(vc, x, zero);
Expr y_positive = vc_gtExpr(vc, y, zero);
Expr two = vc_ratExpr(vc, 2, 1);
Expr twox = vc_multExpr(vc, two, x);
Expr twox_plus_y = vc_plusExpr(vc, twox, y);
Expr three = vc_ratExpr(vc, 3, 1);
Expr twox_plus_y_geq_3 = vc_geExpr(vc, twox_plus_y, three);
Expr formula = vc_impliesExpr(vc, vc_andExpr(vc, x_positive, y_positive),
twox_plus_y_geq_3);
char* formulaString = vc_printExprString(vc, formula);
printf("Checking validity of formula %s with CVC4.\n", formulaString);
printf("CVC4 should return 1 (meaning VALID).\n");
printf("Result from CVC4 is: %d\n", vc_query(vc, formula));
free(formulaString);
return 0;
}
Expr parse()
{
char token[15];
Expr expr = NULL, leftExpr, rightExpr, eqExpr;
readToken(token);
switch(token[0]){
case '+':
leftExpr = parse();
rightExpr = parse();
expr = vc_plusExpr(vc, leftExpr, rightExpr);
break;
case '-':
if(token[1] == '\0'){
leftExpr = parse();
rightExpr = parse();
expr = vc_minusExpr(vc, leftExpr, rightExpr);
}
else{
// assert token[1] is a digit
expr = parseNumber(token);
}
break;
case '*':
leftExpr = parse();
rightExpr = parse();
expr = vc_multExpr(vc, leftExpr, rightExpr);
break;
case '<':
if (token[1] == '='){
leftExpr = parse();
rightExpr = parse();
expr = vc_leExpr(vc, leftExpr, rightExpr);
}
else{
leftExpr = parse();
rightExpr = parse();
expr = vc_ltExpr(vc, leftExpr, rightExpr);
}
break;
case '>':
if (token[1] == '='){
leftExpr = parse();
rightExpr = parse();
expr = vc_geExpr(vc, leftExpr, rightExpr);
}
else{
leftExpr = parse();
rightExpr = parse();
expr = vc_gtExpr(vc, leftExpr, rightExpr);
}
break;
case '=':
leftExpr = parse();
rightExpr = parse();
expr = vc_eqExpr(vc, leftExpr, rightExpr);
break;
case '!':
// assert token[1] == '=';
leftExpr = parse();
rightExpr = parse();
eqExpr = vc_eqExpr(vc, leftExpr, rightExpr);
linkedlist_add(&exprPool, eqExpr);
expr = vc_notExpr(vc, eqExpr);
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
expr = parseNumber(token);
break;
case 'x':
expr = hashmap_get(&vars, token);
if (expr == NULL){
expr = vc_varExpr(vc, token, intType);
char* token_copy = (char*) malloc(sizeof(char)*(strlen(token)+1));
strcpy(token_copy, token);
hashmap_put(&vars, token_copy, expr);
linkedlist_add(&exprPool, expr);
}
return expr;
case 'r':
expr = hashmap_get(&vars, token);
if (expr == NULL){
expr = vc_varExpr(vc, token, realType);
char* token_copy = (char*) malloc(sizeof(char)*(strlen(token)+1));
strcpy(token_copy, token);
hashmap_put(&vars, token_copy, expr);
linkedlist_add(&exprPool, expr);
}
return expr;
default:
printf( "%s", token);
throwRuntimeException( "unexpected type of token" );
}
linkedlist_add(&exprPool, expr);
return expr;
}
value caml_vc_multExpr(value vc, value e1, value e2)
{
CAMLparam3(vc,e1,e2);
CAMLreturn(alloc_Expr(vc_multExpr(VC_val(vc),Expr_val(e1),Expr_val(e2))));
}
