bug#67611: [PATCH] Add a Pcase pattern `cl-lambda` equivalent to `cl-destructuring-bind`

[Stefan Monnier]

> The attached patch adds the pattern `cl-lambda` for Pcase, which works
> like `cl-destructuring-bind`. There are two differences with the lambda
> lists:

Hmm... I'm not sure mixing the CL destructuring patterns with the Pcase
patterns (both of which are rather featureful and complex) will help
their popularity.

Beside that problem (which means I'm not very favorable to the
addition), the name should be changed because "lambda" is misleading.
It suggests this has to do with a function (I had to read the code to
understand what this is doing).

> The pattern is useful when one wants to combine the features of `pcase`
> and `cl-destructuring-bind`, such combining the optional values with the
> `pred` or `guard` patterns.

Do you have examples uses?

Maybe we could introduce a different Pcase pattern which covers those
needs but stays closer to the Pcase pattern syntax?


        Stefan