exercise 1.13 has a question.

[lyerox]

Should need (null? slist) test with the definition of kleene star pattern ?

[dwayne]

@lyerox No you wouldn't need to deconstruct the slist when using map.

[Zeta611]

Actually, I believe it is wrong to add the null checking, as the text explicitly told us to follow the original grammar (using the Kleene's star), not the decomposed grammar.