Erlang "unbound variable" when calling a function

Question

I am trying to pass an integer parameter N to `cake` and return a list of size N of the square of 2 (for the sake of example). e.g. bakery:cake(3) => [4,4,4] Here is what I have attempted so far: ``` -module(bakery). -export([cake/1]). Foo = fun(X) -> X * X end. cake(0) -> []; cake(N) when N > 0 -> [ Foo(2) | cake(N-1) ]. ``` When I compile the code `c(bakery).` in erl however, I get the following error trace: ``` bakery.erl:4: syntax error before: Foo bakery.erl:7: variable 'Foo' is unbound error ``` I am still getting used to anonymous functions and erlang in general coming an object-oriented world. Any help would be appreciated.

Accepted Answer

Each Erlang module, as described here, should consist of a sequence of attributes and function declarations, each terminated by period (.)

But this line:

```
Foo = fun(X) -> X * X end.
```

... is neither and should be written as follows instead:

```
foo(X) -> X * X.
```

`foo` is lowercase here, because this line is a function declaration, where function name should be an atom.

So in the end your module will look like this:

```
-module(bakery).
-export([cake/1]).

foo(X) -> X * X.

cake(0) -> [];
cake(N) when N > 0 -> [ foo(2) | cake(N-1) ].
```

Erlang "unbound variable" when calling a function

Solution

Problem