Re: Question on pcase

[Michael Heerdegen]

Oleh Krehel <address@hidden> writes:

> I think that we should at least encourage `pcase' to macroexpand to a
> simple `cond' with a regular structure every time.

If you mean to expand a single branch into a `cond' with a regular
structure: The semantics of `pcase' is too complex for that.  In
general, you have a decision _tree_, because patterns can depend on each
other, hence you can't expand to a `cond' form in the general case.
Instead, you have a tree of nested `if's, combined with let bindings
(that are used to construct the environment of bindings created by the
pattern parts matched "so far").


Michael.