[R6RS] R6RS Unicode SRFI controversial issues

[Anton van Straaten]

Michael Sperber wrote:
> Anton van Straaten <anton at appsolutions.com> writes:
...
>>When you see "#<<THING", you know you need to look on the next line for 
>>the data which it references.  The data has already been extracted from 
>>the source location which references it.  There's no need to abstract it 
>>further by binding an ordinary lexical name to it, unless you need to 
>>reuse the string, or define it a greater distance from where you use it.
> 
> 
> Huh.  My gut tells me this is a total hack, yet my brain doesn't seem
> to be able to poke an honest hole in it, other than the complications
> in implementing the reader.  Does it scale to multiple arguments?
> 
> $data = foo(<<THING1, <<THING2, arg3, arg4);
> This is the value of THING1
> THING1
> This is the value of THING2
> THING2

Yes, that's exactly how it works, in Perl at least.

BTW, I notice that PLT v299 also supports the scsh-style syntax, and 
Guile has it as a module (part of a Scsh port).

I think the hackish feel of the full Perl-style mechanism comes mainly 
from being un-Scheme-like.  It allows separation of the literal text 
from the place where the text is used, in a way that's unlike anything 
else in Scheme.

OTOH, the scsh mechanism only allows strings to be quoted in-place, so 
is just a special kind of literal string quotation that isn't 
particularly surprising in a Scheme context.

Despite the initial surprise of the Perl style, though, I think it could 
be useful in making s-exps cleaner, for example:

Scsh-style:

(let ((thing1 #<<THING1
This is the value of THING1
THING1
)
       (thing2 #<<THING2
This is the value of THING2
THING2
))
   ; use thing1 and thing2 here
)

Perl-style:

(let ((thing1 #<<THING1) (thing2 #<<THING2))
This is the value of THING1
THING1
This is the value of THING2
THING2
   ; use thing1 and thing2 here
)

But as I said, I'm much more interested in having support for blocks of 
unescaped text, than I am in the exact syntax or features used to 
achieve that.

Anton