String reboot (plain text)

[Stephen Colebourne]

On Wed, 13 Mar 2019 at 17:52, Brian Goetz <brian.goetz at oracle.com> wrote:
> So, in the spirit of “keep ordering until sated, but stop there”, here are some reasonable choices.
>
> 1.  Do multi-line (escaped) strings with a “”” fixed delimiter.  Large benefit, small cost.  Most embedded snippets don’t need any escaping.  Low cost, big payoff.
>
> 1a.  Do 1, but automatically reflow multi-line strings using the equivalent of String::align.  There have been reasonable proposals on how to do this; where they fell apart is the interaction with raw-ness, but if we separate ML and raw, these become reasonable again.  Higher cost, but higher payoff; having separated the interaction with raw strings, this is more defensible.
>
> 2.  Do (1) or (1a), and add: single-line raw string literals delimited by \”…”\.
>
> 2a.  Do (1) or (1a), and also support multi-line raw string literals (where we _don’t_ automatically apply String::align; this can be done manually).  Note that this creates anomalies for multi-line raw string literals starting with quotes (this can be handled with concatenation, and having separated ML and raw, this is less of a problem than before).
>
> 3.  Do (2) and (2a), and also support a repeating compound delimiter with multiple backslashes and a quote.

My views have not changed dramatically from my last mail [1]. As per
these options, I think the language would benefit from 1, 1a, 2 and 2a
type changes. I think the choice between 1 and 1a is a false one. I'm
not convinced 3 is worth pursuing.

I agree that triple double-quote is the right mechanism for multi-line
strings - an obvious direction for Java. I'm happy to accept 1 on its
own *providing that 1a can be added later*. My preference is for """
to be the delimiter for non-aligned multi-line strings, and for a
single letter prefix 'a' to be used for aligned strings, eg. a""" ...
"""

For raw strings I personally find the syntax /" ... "/ or /""" ...
"""/ unpleasant. While the argument of "distributing the escape over
the string" makes some sense in the abstract, the result is not
appealing to read. Given that I believe aligned and non-aligned
strings should be separated by a single letter prefix, I believe that
raw strings and non-raw strings should also be separated by a single
letter prefix:

 """ - multi-line with-escapes & non-aligned
 a""" - multi-line with-escapes & aligned
 r""" - multi-line raw & non-aligned
 ra""" - multi-line raw & aligned
 " - single-line with-escapes
 r" - single-line raw

And yes, I do think you can have raw and aligned as a combination. I
think using prefix letters is more extensible, more orthogonal and
clearer than using /""" ... """/.

thanks
Stephen

[1] https://mail.openjdk.java.net/pipermail/amber-dev/2019-January/003850.html