On Fri, Oct 18, 2019 at 6:39 PM Steven D'Aprano <steve@pearwood.info> wrote:
You seem to have come up with a completely unique symbol which has, as
far as I can tell, never been used before. As far as I can see, neither
APL nor Perl use it as an operator. I can't see it in Unicode, or as an

What is funny, it was not at all my original goal, I just went ahead about what would visually most closely express the operation behind. The fact that it turned out to be an unexpected symbol was just incidental. But you can also take it as a measure how far/close it is to "add", or "concatenation" (at least for me).

It could be interpreted as an attempt to render the "not less-than"
mathematical symbol ≮ U+226E in pure ASCII Variants of that glyph
sometimes use a vertical, rather than slanted, bar.

Take it as placeholder, I am not going to argue about all the different implications it could have, nor insisting on it being the right symbol for the task.
Perhaps it does. But inventing obscure and cryptic symbols like |<
simply hides the fundamental similarities between adding two
dictionaries and other forms of addition.

Dictionary "merge" is as close to addition or concatenation as union set is, which means not much really (otherwise we would intuitively use '+' also for union). We could as well use '+' for writing into the file (because for the file object it "adds" something to it), but we don't. There is a difference between what the object can take and what is already established in the language. There has been other remarks on this thread that '+' symbol "does not feel exactly right" and this is the reason. The PEP actually never adresses it directly too, it just goes around about how '+' symbol is used for different operations in different contexts (which should technically prove that there is no "intuitive" interpretation, because it could do anything) and that considering this, the proposed use should be alright too.