Re: Including some functions from dash.el in Emacs?

[Stefan Monnier]

> think it would be great if Elisp had them builtin, like `flatten`,
> `filter` or `reduce`.

IIUC, `filter' is covered by `cl-remove-if`, and `reduce' is called
`cl-reduce', right?

As for `flatten', all the examples I've seen where it's used have been
either cases where I think that using a different structure would have
made simpler&clearer code (and removed the need for `flatten'), or where
you really really got lucky.

If you think about types, flatten can't make sense for lists (since
lists are typically "lists of <something>" but not "list of list of list
of list of list ..."), so it is only really useful for trees where it
gives you the in-order elements of the tree, so it only works for trees
with no extra meta info.  In those tree cases, I believe that
a tree-traversal-iterator would be more useful.

> Would it make sense to include some of the dash.el functions into Emacs?

I'm in the process of trying to get dash.el included in GNU ELPA.
I haven't decided yet whether or when it should go into Emacs or stay
in GNU ELPA.


        Stefan