private bool IsChained(BinaryExpr expression)
{
if (!expression.Op.Equals(BinaryExpr.Opcode.And))
{
return(false);
}
var lhs = expression.E0 as BinaryExpr;
var rhs = expression.E1 as BinaryExpr;
if (lhs == null || rhs == null)
{
return(false);
}
return(BinaryExpr.IsEqualityOp(lhs.Op) && BinaryExpr.IsEqualityOp(rhs.Op));
}
protected Expression EvaluateExpression(ExpressionTree expt, ProofState state)
{
Contract.Requires(expt != null);
if (expt.IsLeaf())
{
return(EvaluateLeaf(expt, state) as LiteralExpr);
}
var bexp = (BinaryExpr)expt.Data;
if (BinaryExpr.IsEqualityOp(bexp.Op))
{
bool boolVal = EvaluateEqualityExpression(expt, state);
return(new LiteralExpr(new Token(), boolVal));
}
var lhs = EvaluateExpression(expt.LChild, state) as LiteralExpr;
var rhs = EvaluateExpression(expt.RChild, state) as LiteralExpr;
// for now asume lhs and rhs are integers
var l = (BigInteger)lhs?.Value;
var r = (BigInteger)rhs?.Value;
BigInteger res = 0;
switch (bexp.Op)
{
case BinaryExpr.Opcode.Sub:
res = BigInteger.Subtract(l, r);
break;
case BinaryExpr.Opcode.Add:
res = BigInteger.Add(l, r);
break;
case BinaryExpr.Opcode.Mul:
res = BigInteger.Multiply(l, r);
break;
case BinaryExpr.Opcode.Div:
res = BigInteger.Divide(l, r);
break;
}
return(new LiteralExpr(lhs.tok, res));
}