Likewise, I do see why this is a little troublesome. It's annoying when you
mean to write `for i = 1:n` but accidentally write `for i = n`; it's not
always an easy bug to find.
--Tim
On Tuesday, December 01, 2015 06:38:46 PM Eric Forgy wrote:
> It bugs me, but only a little, so I won't lose sleep over it :)
>
> Then again, I wish Julia had a "strict" mode. In strict mode, the language
> would be more pure mathematically, e.g. scalars have no indices, the
> transpose of a vector is a covector, etc. This bit me recently because if T
> <: U, then Array{T} is NOT <: Array{U} although as, sub-modules
> <https://en.wikipedia.org/wiki/Module_(mathematics)>, Tmodule <: Umodule.
>
> Then again, as I'm learning, if we want Julia to do something bad enough,
> e.g. have a "strict" mode, we can have it. For example, I could write a
> package "strict.jl" where
>
> using strict
>
> would kill Base.getindex(::Number) and things like that. That could be cool
>
> :)
>
> On Wednesday, December 2, 2015 at 9:38:50 AM UTC+8, Tim Holy wrote:
> > On Tuesday, December 01, 2015 03:19:33 PM Eric Forgy wrote:
> > > A scalar is distinct from a vector so size(a) = () makes sense. getindex
> >
> > for
> >
> > > a scalar does not make sense and should probably be removed on the
> >
> > grounds
> >
> > > of mathematical elegance :) Any code that depends on referencing a
> >
> > scalar
> >
> > > via an index is probably flawed in the first place.
> >
> > Conversely, there are many people who seem to want Julia to treat scalars
> > and
> > 1-vectors indistinguishably (ala Matlab).
> >
> > For what it's worth, here's a (contrived) example to justify the current
> > behavior:
> >
> > function sum_over_dims(A, dims)
> >
> > for d in dims
> >
> > A = sum(A, d)
> >
> > end
> > A
> >
> > end
> >
> > sum_over_dims(A, [2,3])
> > sum_over_dims(A, 2)
> >
> > Why should I write sum_over_dims(A, [2]) in the latter case?
> >
> > Best,
> > --Tim
