A list of expressions is defined by e % sep which is equivalent to e (sep e)* in term of parsing but not equivalent in term of types. Indeed the first expression will have the type Vec<E> while the second (E, Vec<E>) or (E, Vec<(E, Sep)>) if the separator has a type different from () or (^).
e % sep has the type Vec<E> and sepmust have the type () (or (^)) or a typing error should be exposed.
A list of expressions is defined by
e % sepwhich is equivalent toe (sep e)*in term of parsing but not equivalent in term of types. Indeed the first expression will have the typeVec<E>while the second(E, Vec<E>)or(E, Vec<(E, Sep)>)if the separator has a type different from()or(^).e % sephas the typeVec<E>andsepmust have the type()(or(^)) or a typing error should be exposed.