[swift-evolution] [Review] SE-0168: Multi-Line String Literals

Brent Royal-Gordon brent at architechies.com
Wed Apr 12 08:40:16 CDT 2017

Hey folks,

We've revised the proposal again. The main difference: You no longer need an initial newline to enable indentation stripping, and stripping no longer removes that newline even if it is present. (Adrian Zubarev and I believe some others argued for this.) We disagreed with this at first, but it made more sense as we thought about it more. There are a few things we like about it:

	1. The rules and algorithm are simpler.
	2. It accommodates more coding styles.
	3. Every non-escaped newline in the literal now creates a corresponding newline in the resulting string.
	4. it's easy to get the old behavior back by backslashing the leading newline.

Unfortunately, I think this precludes stripping the trailing newline by default, but I think this is ultimately a simpler and better approach than the previous draft.

Other changes:

	* We realized we needed to make closing delimiter matching a little more complicated if we wanted to allow one or two adjacent double-quote characters that were part of the literal's contents. Oops.
	* Tabs aren't actually allowed in ordinary string literals, so we now explicitly mention that as a difference between the two types.
	* We wrote some tests for the prototype (though they haven't been updated for this new version yet). 
	* There were some other wording changes, particularly in the indentation stripping rationale, but nothing that affects the actual design.

I understand John is working on a new version of his toolchain so people can play with the prototype. We hope to have that ready for you all soon.

Let us know what you think of the revisions!

Brent Royal-Gordon

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