On Sat, Jul 28, 2012 at 6:45 PM, David A. Wheeler <dwhee...@dwheeler.com> wrote:
> Alan Manuel Gloria:
>>     Handle multiline comments and other #-foolery.
>>       TODO: Need to add #{weird symbol}# syntax to Guile
>>         compatibility layer.
> Youch, that's a lot of complexity to implement what is notionally a simple 
> capability.
> I'm not sure I understand why this is so complicated.  Can you help me 
> understand why it's hard to localize the support for multiline functions?

Because of the limitations on the read interface (pass in just a port,
get out just a datum).  And the lack of unlimited readahead.

In any case, in a monadic form the support for comment-tag gets hidden
away in the plumbing, but as we are not using a monadic form (this
being Scheme where monadic form is not idiomatic) then any changes in
the plumbing become significant changes *everywhere*.

For example, in the modern-expressions parser I sent on the list a
long way back, I think the changes would have been *much* more
localized into the parser backend.

But since there is no parser backend in the basic implementation,
there is nothing to locally change - every function handles the port
directly, instead of indicating some transformation that will
*eventually* handle the port.

In short, not enough abstraction in the initial implementation ^^

>  Maybe we can change how we interpret something, so we can vastly simplify 
> the implementation.  Before merging, I want to make sure we *have* to go this 
> way; this will have a continuing drag on any other implementation work.  It 
> may be hamper acceptance, if the implementation has to be this ugly; the code 
> will certainly be part of a SRFI proposal.
> In short: Can we find another, simpler way to do this?

Yeah, monads.  Or macros.


Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
Readable-discuss mailing list

Reply via email to