private static Expression CoalesceInternal(CodeBlock currentBlock, Expression left, Expression right, MethodInfo isTrue, bool isReverse)
{
Contract.RequiresNotNull(currentBlock, "currentBlock");
Contract.RequiresNotNull(left, "left");
Contract.RequiresNotNull(right, "right");
// A bit too strict, but on a safe side.
Contract.Requires(left.Type == right.Type, "Expression types must match");
Variable tmp = currentBlock.CreateTemporaryVariable(SymbolTable.StringToId("tmp_left"), left.Type);
Expression condition;
if (isTrue != null)
{
Contract.Requires(isTrue.ReturnType == typeof(bool), "isTrue", "Predicate must return bool.");
ParameterInfo[] parameters = isTrue.GetParameters();
Contract.Requires(parameters.Length == 1, "isTrue", "Predicate must take one parameter.");
Contract.Requires(isTrue.IsStatic && isTrue.IsPublic, "isTrue", "Predicate must be public and static.");
Type pt = parameters[0].ParameterType;
Contract.Requires(TypeUtils.CanAssign(pt, left.Type), "left", "Incorrect left expression type");
condition = Call(isTrue, Assign(tmp, left));
}
else
{
Contract.Requires(TypeUtils.CanCompareToNull(left.Type), "left", "Incorrect left expression type");
condition = Equal(Assign(tmp, left), Null(left.Type));
}
Expression t, f;
if (isReverse)
{
t = Read(tmp);
f = right;
}
else
{
t = right;
f = Read(tmp);
}
return(Condition(condition, t, f));
}
private static Expression CoalesceInternal(Expression left, Expression right, MethodInfo isTrue, bool isReverse, out ParameterExpression temp)
{
ContractUtils.RequiresNotNull(left, "left");
ContractUtils.RequiresNotNull(right, "right");
// A bit too strict, but on a safe side.
ContractUtils.Requires(left.Type == right.Type, "Expression types must match");
temp = Expression.Variable(left.Type, "tmp_left");
Expression condition;
if (isTrue != null)
{
ContractUtils.Requires(isTrue.ReturnType == typeof(bool), "isTrue", "Predicate must return bool.");
ParameterInfo[] parameters = isTrue.GetParameters();
ContractUtils.Requires(parameters.Length == 1, "isTrue", "Predicate must take one parameter.");
ContractUtils.Requires(isTrue.IsStatic && isTrue.IsPublic, "isTrue", "Predicate must be public and static.");
Type pt = parameters[0].ParameterType;
ContractUtils.Requires(TypeUtils.CanAssign(pt, left.Type), "left", "Incorrect left expression type");
condition = Expression.Call(isTrue, Expression.Assign(temp, left));
}
else
{
ContractUtils.Requires(TypeUtils.CanCompareToNull(left.Type), "left", "Incorrect left expression type");
condition = Expression.Equal(Expression.Assign(temp, left), AstUtils.Constant(null, left.Type));
}
Expression t, f;
if (isReverse)
{
t = temp;
f = right;
}
else
{
t = right;
f = temp;
}
return(Expression.Condition(condition, t, f));
}
