Compile Subexpression Type specification for a List type?

Questions
1

The example in the documentation is for a subexpression that returns an integer:

In[24]:= com[i_] := Binomial[2 i, i]

In[26]:= t1 = 
 Compile[{x, {i, _Integer}}, x^com[i], {{com[_], _Integer}}]

What do I do if my subexpression returns a List of Integers?
Replacing _Integer with {_Integer,1} gives an error message: Invalid type or rank specification.

2

Hi Frank, a simple example worked for me. How do you get the error?

In[1]:= returnList[i_] := {i, 2 i, 3 i}

In[2]:= t3 = 
  Compile[{{x, _Real}, {k, _Integer}}, 
   x returnList[k], {{returnList[_], _Integer, 1}}];

In[3]:= t3[2.3, 2]

Out[3]= {4.6, 9.2, 13.8}
3

I tried to do it with an extra set of brackets around _Integer and 1.
I see that what you did is the way the inputs are specified, which makes more sense.

Thanks