+1 for "do function(f)"
--Tim
On Monday, April 28, 2014 11:11:58 AM Kevin Squire wrote:
> On Mon, Apr 28, 2014 at 10:58 AM, Jason Grout
>
> <jason-s...@creativetrax.com>wrote:
> > On 4/28/14, 12:53, Simon Byrne wrote:
> >> On Monday, 28 April 2014 17:06:37 UTC+1, Simon Byrne wrote:
> >> My own perspective is that this is due to two reasons
> >>
> >> 1) `do` is the only (non-macro) construction that rewrites
> >> expressions i.e.
> >>
> >> open("outfile", "w") do f
> >>
> >> write(f, data)
> >>
> >> end
> >>
> >> does not (directly at least) call the method `open("outfile", "w")`
> >>
> >> Also, the fact that rewriting occurs due to a term that appears *after*
> >> a completed expression I think adds to the confusion. Perhaps this would
> >> be less confusing if some indicator had to appear before the `open`
> >> statement. For example, we could have a macro:
> >>
> >> @do open("outfile", "w") f begin
> >>
> >> write(f, data)
> >>
> >> end
> >
> > Then we're almost to the python syntax:
> >
> > with open("outfile", "w") as f:
> > f.write(data)
>
> Since the actually functionality of `do` is passing the block as an
> anonymous function to `open` et al., this doesn't always work. Consider
>
> get!(mydict, "key") do
> f(key)
> end
>
> This is equivalent to
>
> get!(()->f(key), mydict, "key")
>
> It's unclear to me how this would work using Python's "with ... as" syntax.
>
> I was also confused by the do syntax at first. In particular, it's unclear
> to me that the block is an anonymous function, and I'd prefer that be made
> explicit. Maybe something like
>
> open("outfile", "w") do (f) -> write(f, data)
>
> or
>
> open("outfile", "w") do function(f)
> write(f, data)
> end
>
> It's more verbose, but I'd argue it's also clearer. The `get!` example
> would then be
>
> get!(mydict, "key") do () -> f(key)
>
> or
>
> get!(mydict, "key) do function()
> f(key)
> end
>
>
> Cheers,
>
> Kevin
