Re: [Readable-discuss] My first attempt: a process manager

[David A. W. <dwh...@dw...>]

> On Sat, Jan 4, 2014 at 12:07 AM, Mike Gran <sp...@ya...> wrote:
> > Hi.  I thought I'd take a stab at using your readable project
> >
> > Result is attached.  It is a process manager: a structure holds
> > a list of functions and data and call the functions as a unit.
> > Functions that return #f are removed from the manager, and
> > functions that return #t are kept.
> >
> >
> > My impressions are pretty favorable.  I didn't love the
> > let block syntax, so I used defines instead.

I'm really glad they were overall favorable.


On Fri, 10 Jan 2014 21:08:06 +0800, Alan Manuel Gloria <alm...@gm...> wrote:
> Yes, let syntax is a big drawback with the "indentation implies
> parentheses" strategy.

Nothing is perfect, but I think it's very reasonable
We have a general solution using leading "\\"
that easily handles all cases, and <*...*> is a useful shorthand for handling
let statements with short variable-definition blocks.

> As a complete aside, in Haskell, there's a special "fallback" rule
> where an error due to indentation matching will cause the parser to
> attempt to close a group.  This rule usually triggers in Haskell's
> let...in syntax (basically, the "in" keyword is generally a syntax
> error except after a let group, so the parser usually errors here when
> indentation is used), which seems to imply to me that even Haskell has
> some trouble with let syntax, which was simply "fixed" with this
> hackish solution.
> 
> xref http://www.haskell.org/onlinereport/syntax-iso.html#sect9.3 ,
> particularly Note 5.

Fair enough.  Again, nothing's perfect.

> >  Also, I used
> > 'cond' in lieu of 'if' because I liked the look of having
> > an 'else'.
> 
> Yes, the "old" syntaxes like that tend to be very pretty in indentation syntax.

I think "if" looks great:
if {x < y}
! x
! y

Obviously if you want a *keyword* to mark the else clause, that doesn't do it,
but in that case "cond" is the better choice anyway.

--- David A. Wheeler