Alignment algorithm (was: Wrapping up the first two courses)

[Elias N Vasylenko]

On Mon, 2019-04-22 at 12:04 -0400, Brian Goetz wrote:
> > 
> > Ignoring first line, determine least number of leading whitespaces
> > for all
> > non-blank lines.
> > 
> >     String s = """
> >     ................line 1..
> >     ....................line 2.
> >                 """;  ==> 16
>  
> I think we should reconsider whether a non-blank first line means
> that we should consider any indentation on the first line too.  This
> has the likely-beneficial side-effect that having a non-blank
> character immediately following the """ effectively means "no
> stripping." 

I would go the other way and say that any non-blank first line should
mean no stripping at all. A non-blank first line will always have at
least an extra three characters of indentation, so won't line up with
the rest of the string. (Ignoring some questionable (ab)use of 4+ width
tabs.)

I think it's a useful principle that automatic indentation stripping
deals with the  positioning of a string as a whole in 2D space in the
source file, and if the relative positioning of each line appears to be
inconsistently modified then this principle is violated.

Telling users that they can encode this result:
....line 1
....line 2

As either this:
`
	String s = """	               line 1
	               line 2
	           """;
`

Or this:
`
	String s = """    line 1
	               line 2
	           """;
`

Would be hugely inintuitive imo.

Non-empty first lines would still be useful as an opt-out. And I'd
suggest a convention of using this opt-out by escaping the leading
newline, thus making the first line effectively non-empty without
messing up alignment in the source:
`
	String s = """\
	              line 1
	              line 2
	           """;
`

gives:
......................line 1
......................line 2

We can pull a similar trick to opt-out of any closing delimiter
indentation influence:
`
	String s = """
	              line 1
	              line 2\
	           """;
`

gives:
line 1
line 2