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Re: making indentation marker &| implicit

This page is part of the web mail archives of SRFI 108 from before July 7th, 2015. The new archives for SRFI 108 contain all messages, not just those from before July 7th, 2015.

On 05/27/2013 06:39 PM, Alex Shinn wrote:
On Tue, May 28, 2013 at 10:09 AM, Per Bothner <per@xxxxxxxxxxx
<mailto:per@xxxxxxxxxxx>> wrote:

    ... Scribble avoids this in a way that seems nicer:
    Any indentation that is common to each line
   (following a newline) is stripped.

This is the part that always bothered me, and why I didn't
implement indentation removal.  Many of the examples are
unintuitive, and the rule itself does not seem to be consistent.

For example, the docs have


reads as

(foo "bar""\n"

Why?  The indentation of the leading bar is deeper in the
source port than the following lines, yet shallower in the
string.  How does it get the same result indentation?

I agree - it is rather "magic".
My guess is they wanted to support the following two styles:




and so tried to define rules to support those.



doesn't really make sense.

Unsure of the right semantics, it seemed simpler to leave
this out since it's easy enough to specify arbitrary trimming
behavior separately:


Well, that becomes tedious if you have to do it often.

    Tabs would have to be consistent: If a line starts with
    T1 tabs followed by S1 spaces, and another line starts with
    T2 tabs followed by S2 spaces, then it is an error if
    (and (not (= T1 T2)) (> S1 0) (> S2 0)).

I presume you mean not an error, just not the same indentation?

I mean an error - it indicates ambiguous use of TABs.

... alternately just define a tab as 8 spaces.

That is fine in a Unix-based culture.  Some programming
cultures use TAB to mean "indentation unit", which can
be set according to user preference.  I.e. TAB is a
flexible user-settable length.  Thus if you use TABS
inconsistently the indentation is ambiguous, and I thin
at least deserves a warning.
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/