Can we skip ahead to considering how to implement this? I can think of two
approaches: either hack the lexer to special-case a newline followed by a
period (which currently can never start a line), or redesign the syntax to
allow NEWLINE INDENT ‘.’ ......... NEWLINE ‘.’ ............ DEDENT at the
end of an expression. Both have pros and cons.
Discuss how this allows for certain typos to pass as valid syntax.
On Fri, Mar 12, 2021 at 07:42 Matt Williams <m...@milliams.com> wrote:
> Hi,
>
> It's becoming more popular in Python to have interfaces which are built
> around method chaining as a way of applying operations to data. For example
> in pandas is moving more towards a default model where methods do not
> change the object in-place but instead return an altered version (or at
> least an altered view) of it.
>
> The major downside to method chaining is that it ends up creating long
> lines of code which can become hard to read. The two main solutions to this
> are 1) break down the chain and give the steps their own variable names and
> 2) split it over multiple lines using `\` as a line continuation.
>
> e.g.:
>
> y = x.rstrip("\n").split(":")[0].lower()
>
> would become
>
> y = x.rstrip("\n") \
> .split(":")[0] \
> .lower()
>
> I find the continuation character visually distracting, easy to forget and
> does not allow for line-by-line commenting (causing `SyntaxError:
> unexpected character after line continuation character`):
>
> y = x.rstrip("\n") \
> .split(":")[0] \ # grab the key name
> .lower()
>
> My idea is to alter the syntax of Python to allow doing:
>
> y = x.rstrip("\n")
> .split(":")[0]
> .lower()
>
> i.e., not requiring an explicit line continuation character in the case
> where the next line starts with a period.
>
> I've had a search through the archives and I couldn't see this discussion
> before. Feel free to point me to it if I've missed anything.
>
> Cheers,
> Matt
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