On Wednesday, December 02, 2015 05:11:32 AM Seth wrote:
> This is great. I assume it catches "for i in n" where n is a scalar, also,
> right?
>
> I could see requiring this by default in all my packages.
Might be better as a test dependency, since it works by "breaking" methods in
Base. If you include it in your package by default, you risk fragmenting Julia
into incompatible dialects.
--Tim
>
> On Wednesday, December 2, 2015 at 1:49:22 AM UTC-8, Eric Forgy wrote:
> > Some more improvements...
> >
> > julia> n = 5
> > 5
> >
> > julia> for i = n
> >
> > println(i)
> > end
> >
> > 5
> >
> > julia> using strict
> >
> > julia> for i = n
> >
> > println(i)
> > end
> >
> > ERROR: MethodError: `start` has no method matching start(::Type{Number})
> >
> > in start at C:\Users\Eric Forgy\.julia\v0.4\strict\src\strict.jl:24
> >
> > On Wednesday, December 2, 2015 at 12:05:07 PM UTC+8, Eric Forgy wrote:
> >> It's a start :)
> >>
> >> https://github.com/EricForgy/strict.jl
> >>
> >>
> >> julia> using strict
> >>
> >> julia> a = 5
> >> 5
> >>
> >> julia> a[1]
> >> ERROR: MethodError: `getindex` has no method matching getindex(::Type{
> >> Number}, ::Type{Integer})
> >>
> >> Closest candidates are:
> >> getindex(::Type{T}, ::Any...)
> >> getindex{T<:Union{Char,Number}}(::Type{T<:Union{Char,Number}}, ::Range{
> >>
> >> T})
> >>
> >> getindex{T<:Union{Char,Number}}(::Type{T<:Union{Char,Number}}, ::Range{
> >>
> >> T}, ::Range{T}...)
> >>
> >> in getindex at C:\Users\Eric Forgy\.julia\v0.4\strict\src\strict.jl:4
> >>
> >> On Wednesday, December 2, 2015 at 11:02:45 AM UTC+8, Tim Holy wrote:
> >>> 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
