BinaryExpr implementation
BinaryExpr::BinaryExpr
(const char* oper,
Expr* l, Expr* r):
OpExpr(oper), lhs(l), rhs(r) { }
BinaryExpr::~BinaryExpr()
{ delete lhs; delete rhs; }
void BinaryExpr::print(FILE* f) {
fprintf(f, ``(''); lhs->print(f);
fprintf(f, op); rhs->print(f);
fprintf(f, ``)'');
}