Additions to the .rx namespace

philippjfr commented 7 months ago

As we have started building applications with rx a few gaps have become clear, specifically the following functionality is currently missing:

[x] Allow constructing "empty" rx() which initializes with a None value
[x] Currently there is no way to get the equivalent to the not keyword, therefore we introduce .rx.not_
[x] It is quite awkward to apply a function to each item in an iterable, therefore we introduce .rx.map
[x] Currently there is no way to achieve equivalent to the and keyword, therefore we introduce .rx.and_
[x] Currently there is no way to achieve equivalent to the or keyword, therefore we introduce .rx.or_
[x] Add support for an initial value on .param.when so that the expression isn't evaluated until the first event is triggered
[x] Allow .rx.watch() without args to make expression evaluate eagerly
[x] Update docs

jbednar commented 7 months ago

Thanks. Not sure how we missed some of those earlier. The doc page also needs updating.

philippjfr commented 7 months ago

Thanks. Not sure how we missed some of those earlier. The doc page also needs updating.

I did not fully appreciate that and, or and not cannot be overloaded in Python, only the equivalent boolean operators &, | and ~ can.

MarcSkovMadsen commented 7 months ago

Why are the underscores needed?

jbednar commented 7 months ago

Python keywords cannot be identifiers.

holoviz / param