private IEnumerable <object> ResolveExpression(Expression expr, IVariable declaration)
{
Contract.Requires(expr != null);
if (expr is BinaryExpr)
{
BinaryExpr bexp = expr as BinaryExpr;
switch (bexp.Op)
{
case BinaryExpr.Opcode.In:
NameSegment var = bexp.E0 as NameSegment;
Contract.Assert(var != null, Error.MkErr(bexp, 6, declaration.Name));
Contract.Assert(var.Name == declaration.Name, Error.MkErr(bexp, 6, var.Name));
foreach (var result in ResolveExpression(bexp.E1))
{
if (result is IEnumerable)
{
dynamic resultList = result;
foreach (var item in resultList)
{
yield return(item);
}
}
}
yield break;
case BinaryExpr.Opcode.And:
// for each item in the resolved lhs of the expression
foreach (var item in ResolveExpression(bexp.E0, declaration))
{
Atomic copy = Copy();
copy.AddLocal(declaration, item);
// resolve the rhs expression
foreach (var res in copy.ResolveExpression(bexp.E1))
{
LiteralExpr lit = res as LiteralExpr;
// sanity check
Contract.Assert(lit != null, Error.MkErr(expr, 17));
if (lit.Value is bool)
{
// if resolved to true
if ((bool)lit.Value)
{
yield return(item);
}
}
}
}
yield break;
}
}
}